Tag Archives: depth of field

Sensor Size and Depth of Field

It is commonly said that crop sensor cameras make images having both a narrower field of view and a greater depth of field. Well, that's partly right. (Bill Ferris)

It is commonly said that crop sensor cameras make images having both a narrower field of view and a greater depth of field. Well, that’s partly right. (Bill Ferris)

It is well-known that a lens of a given focal length will deliver different angles of view when used with cameras having different sized sensors. For example, the above image was made with a Nikon D90 and a Nikkor 200-500mm f/5.6E telephoto zoom lens at 500mm. The D90 is a DX format camera having a 1.5x crop factor. In other words, the DX sensor crops the outer portion of the image formed by the lens. As a result, photographs made with this camera will display an angle of view equivalent to that produced by a lens with 1.5x the actual focal length used. In the above image, the 200-500 is at 500mm but the angle of view matches that produced by a 750mm lens.

It is often said that a crop sensor camera will also produce an image having a greater depth of field. In other words, the same lens at the same focal length will produce, not just a wider angle of view when paired with a full frame camera, but also a shallower depth of field. The claim is that the DX sensor not only crops the angle of view but forces a significant increase in depth of field. That assertion is just plain wrong.

In the below test images, you’ll see side-by-side comparisons of photos made with Nikon FX (full frame) and DX (crop sensor) camera bodies. The cameras used were the full frame Nikon D610 and the DX format Nikon D90. These cameras were used with the following lenses:

  • Nikkor 200-500mm f/5.6E VR
  • Tamrom 70-200mm f/2.8 Di VC USD
  • Tamron 24-70mm f/2.8 Di VC USD

To isolate sensor size as the only variable, the comparison images were made with the lenses at the same focal length, focal ratio and at the same distance from a fixed position subject. The Nikkor 200-500mm f/5.6E and Tamron 70-200mm f/2.8 Di VC USD were mounted on a tripod in a fixed position. The Tamron 24-70mm f/2.8 Di VC USD has no tripod collar or foot. The cameras were mounted to the tripod with the tripod in the same position for each set of exposures.

To create a large enough set of images to suitably address the question, each lens was used at a multiple focal lengths:

  • Nikkor 200-500mm f/5.6E VR: 200mm, 300mm, 400mm and 500mm
  • Tamrom 70-200 f/2.8 Di VC USD: 70mm, 100mm, 135mm and 200mm
  • Tamron 24-70 f/2.8 Di VC USD: 50mm and 70mm

Each lens was used wide open at its smallest f-stop number. ISO and shutter speed were kept constant for exposures made at the same focal length with both cameras.

Why did I decide to test the notion that sensor size has a significant impact on depth of field? I performed this experiment to test my belief that that lens aperture and distance to subject are the two factors having the greatest impact on depth of field. In other words, if a lens is used at the same physical aperture and distance to make photographs of a fixed position subject with two cameras of different sensor size, the depth of field recorded in the two images should be identical or, at least, very nearly so.

If I’m correct in this belief, the images should confirm it. If I’m wrong and if crop factor needs to be applied to depth of field as well as to focal length, photos made under the above conditions should exhibit obviously different depths of field with the photo made using the full frame camera consistently displaying an obviously shallower depth of field than the photo made using the crop sensor body.

Keeping all this in mind, let’s go to the photos. Below, are ten composite images. The photo occupying the left half of each composite was made using the Nikon D610. The photo to the right of the divider was made using the Nikon D90. Since the same lens at the same focal length, f-stop and distance to subject was used to make each image in a composite, the image made with the crop sensor D90 (on the right) shows a narrower angle of view. In each composite, I’ve indicated similar sections of the two photos that, when compared, reveal both photos to have identical – or nearly so – depths of field. This conclusion is reached by comparing the relative size of the subject, a hula dancer toy, and the out of focus highlights and details in the background.

Comparison #1: Nikkor 200-500mm f/5.6E (200mm, f/5.6)

The photo to the left of the divider was made with the Nikon D610 and Nikkor 200-500mm f/5.6E at 200mm, f/5.6, ISO 400, 1/200-second. The photo on the right was made with the same lens at the same distance from subject also at 200mm, f/5.6, ISO 400, 1/200-second. (Bill Ferris)

The photo to the left of the divider was made with the Nikon D610 and Nikkor 200-500mm f/5.6E at 200mm, f/5.6, ISO 400, 1/200-second. The photo on the right was made with the Nikon D90, the same lens at the same distance from subject also at 200mm, f/5.6, ISO 400, 1/200-second. (Bill Ferris)

Comparison #2: Nikkor 200-500mm f/5.6E (300mm, f/5.6)

The photo to the left of the divider was made with the Nikon D610 and Nikkor 200-500mm f/5.6E at 300mm, f/5.6, ISO 400, 1/200-second. The photo on the right was made with the same lens at the same distance from subject also at 300mm, f/5.6, ISO 400, 1/200-second. (Bill Ferris)

The photo to the left of the divider was made with the Nikon D610 and Nikkor 200-500mm f/5.6E at 300mm, f/5.6, ISO 400, 1/200-second. The photo on the right was made with the Nikon D90, the same lens at the same distance from subject also at 300mm, f/5.6, ISO 400, 1/200-second. (Bill Ferris)

Comparison #3: Nikkor 200-500mm f/5.6E (400mm, f/5.6)

The photo to the left of the divider was made with the Nikon D610 and Nikkor 200-500mm f/5.6E at 400mm, f/5.6, ISO 400, 1/250-second. The photo on the right was made with the same lens at the same distance from subject also at 400mm, f/5.6, ISO 400, 1/250-second. (Bill Ferris)

The photo to the left of the divider was made with the Nikon D610 and Nikkor 200-500mm f/5.6E at 400mm, f/5.6, ISO 400, 1/250-second. The photo on the right was made with the Nikon D90, the same lens at the same distance from subject also at 400mm, f/5.6, ISO 400, 1/250-second. (Bill Ferris)

Comparison #4: Nikkor 200-500mm f/5.6E (500mm, f/5.6)

The photo to the left of the divider was made with the Nikon D610 and Nikkor 200-500mm f/5.6E at 500mm, f/5.6, ISO 400, 1/250-second. The photo on the right was made with the same lens at the same distance from subject also at 500mm, f/5.6, ISO 400, 1/250-second. (Bill Ferris)

The photo to the left of the divider was made with the Nikon D610 and Nikkor 200-500mm f/5.6E at 500mm, f/5.6, ISO 400, 1/250-second. The photo on the right was made with the Nikon D90, the same lens at the same distance from subject also at 500mm, f/5.6, ISO 400, 1/250-second. (Bill Ferris)

Comparison #5: Tamron 70-200 f/2.8 VC (70mm, f/2.8)

The photo to the left of the divider was made with the Nikon D610 and Tamron 70-200mm f/2.8 VC at 70mm, f/2.8, ISO 400, 1/400-second. The photo on the right was made with the same lens at the same distance from subject also at 70mm, f/2.8, ISO 400, 1/400-second. (Bill Ferris)

The photo to the left of the divider was made with the Nikon D610 and Tamron 70-200mm f/2.8 VC at 70mm, f/2.8, ISO 400, 1/400-second. The photo on the right was made with the Nikon D90, the same lens at the same distance from subject also at 70mm, f/2.8, ISO 400, 1/400-second. (Bill Ferris)

Comparison #6: Tamron 70-200mm f/2.8 VC (100mm, f/2.8)

The photo to the left of the divider was made with the Nikon D610 and Tamron 70-200mm f/2.8 VC at 100mm, f/2.8, ISO 400, 1/400-second. The photo on the right was made with the same lens at the same distance from subject also at 100mm, f/2.8, ISO 400, 1/400-second. (Bill Ferris)

The photo to the left of the divider was made with the Nikon D610 and Tamron 70-200mm f/2.8 VC at 100mm, f/2.8, ISO 400, 1/400-second. The photo on the right was made with the Nikon D90, the same lens at the same distance from subject also at 100mm, f/2.8, ISO 400, 1/400-second. (Bill Ferris)

Comparison #7: Tamron 70-200mm f/2.8 VC (135mm, f/2.8)

The photo to the left of the divider was made with the Nikon D610 and Tamron 70-200mm f/2.8 VC at 135mm, f/2.8, ISO 400, 1/400-second. The photo on the right was made with the same lens at the same distance from subject also at 135mm, f/2.8, ISO 400, 1/400-second. (Bill Ferris)

The photo to the left of the divider was made with the Nikon D610 and Tamron 70-200mm f/2.8 VC at 135mm, f/2.8, ISO 400, 1/400-second. The photo on the right was made with the Nikon D90, the same lens at the same distance from subject also at 135mm, f/2.8, ISO 400, 1/400-second. (Bill Ferris)

Comparison #8: Tamron 70-200mm f/2.8 VC (200mm, f/2.8)

The photo to the left of the divider was made with the Nikon D610 and Tamron 70-200mm f/2.8 VC at 200mm, f/2.8, ISO 400, 1/400-second. The photo on the right was made with the same lens at the same distance from subject also at 200mm, f/2.8, ISO 400, 1/400-second. (Bill Ferris)

The photo to the left of the divider was made with the Nikon D610 and Tamron 70-200mm f/2.8 VC at 200mm, f/2.8, ISO 400, 1/400-second. The photo on the right was made with the Nikon D90, the same lens at the same distance from subject also at 200mm, f/2.8, ISO 400, 1/400-second. (Bill Ferris)

Comparison #9: Tamron 24-70mm f/2.8 VC (50mm, f/2.8)

The photo to the left of the divider was made with the Nikon D610 and Tamron 24-70mm f/2.8 VC at 50mm, f/2.8, ISO 400, 1/640-second. The photo on the right was made with the same lens at the same distance from subject also at 50mm, f/2.8, ISO 400, 1/640-second. (Bill Ferris)

The photo to the left of the divider was made with the Nikon D610 and Tamron 24-70mm f/2.8 VC at 50mm, f/2.8, ISO 400, 1/640-second. The photo on the right was made with the Nikon D90, the same lens at the same distance from subject also at 50mm, f/2.8, ISO 400, 1/640-second. (Bill Ferris)

Comparison #10: Tamron 24-70mm f/2.8 VC (70mm, f/2.8)

The photo to the left of the divider was made with the Nikon D610 and Tamron 24-70mm f/2.8 VC at 70mm, f/2.8, ISO 400, 1/640-second. The photo on the right was made with the same lens at the same distance from subject also at 70mm, f/2.8, ISO 400, 1/640-second. (Bill Ferris)

The photo to the left of the divider was made with the Nikon D610 and Tamron 24-70mm f/2.8 VC at 70mm, f/2.8, ISO 400, 1/640-second. The photo on the right was made with the Nikon D90, the same lens at the same distance from subject also at 70mm, f/2.8, ISO 400, 1/640-second. (Bill Ferris)

Comparing the above ten photo sets, it’s clear the photographs capture equivalent depths of field despite the fact that they’re made with full frame and crop sensor cameras. As expected, the crop sensor camera captures a more narrow angle of view. However, a comparison of the relative size of the hula dancer toy with the details of the out of focus background reveals that the DX format Nikon D90 captures the same depth of field as the FX format Nikon D610. This flies in the face of the common (but mistaken) belief that crop sensors significantly alter depth of field.

To understand the performance of each camera as illustrated in the above photos, one need only understand that photographic depth of field is largely determined by two factors: distance to subject and lens aperture. Each lens was kept at a constant position and distance from the subject for the photos made with the two camera bodies. By keeping focal length and f-stop constant in each photographic set, lens aperture was kept constant.

The f-stop number describes the ratio of lens focal length to aperture. In other words, a 200mm, f/5.6 lens has an aperture of about 36mm. This is true regardless of the size of the sensor in the camera to which the lens is attached. Here’s a listing of the focal lengths and apertures for each set of photos:

Nikkor 200-500mm f/5.6E VR

  • 36mm aperture (200mm, f/5.6)
  • 54mm aperture (300mm, f/5.6)
  • 71mm aperture (400mm, f/5.6)
  • 89mm aperture (500mm, f/5.6)

Tamron 70-200mm f/2.8 VC

  • 25mm aperture (  70mm, f/2.8)
  • 36mm aperture (100mm, f/2.8)
  • 48mm aperture (135mm, f/2.8)
  • 71mm aperture (200mm, f/2.8)

Tamron 24-70mm f/2.8 VC

  • 18mm aperture (50mm, f/2.8)
  • 25mm aperture (70mm, f/2.8)

As you review the above list, notice the constant f-stop results in increasing lens aperture as focal length increases. By keeping subject distance constant and increasing the physical aperture of the lens, depth of field becomes more shallow. By definition, the reverse is also true. With subject distance kept constant, decreasing lens aperture would result in a deeper or increased depth of field. And as illustrated by the above comparisons, keeping both subject distance and lens aperture constant produces constant depth of field. This holds true regardless of sensor size.

How is it, then, that so many photographers have come to accept the false assertion that crop sensor cameras make images having increased depth of field? The key to understanding this is the concept of equivalence. In simplest terms, equivalence describes two images made with different cameras and lens settings but having identical qualities. There are many factors that go into describing truly equivalent images. For the purposes of this discussion, we’ll focus on angle of the view and depth of field.

This set of images compares performance between crop sensor and full frame DSLR bodies. The images in the left column were made with a Nikon D90. Images in the right three columns were made with a Nikon D610. Both cameras used the same Tamron 70-200mm f/2.8 Di VC USD zoom lens, which was set up on a tripod to ensure it would not change position during the test. Both cameras used ISO 200, center point average metering and were operated in Aperture Priority. The subject in these photos is a scale model of the Lunar Excursion Module (LEM) from the Apollo program.

This set of images compares performance between crop sensor and full frame DSLR bodies. The images in the left column were made with a Nikon D90. Images in the right three columns were made with a Nikon D610. Both cameras used the same Tamron 70-200mm f/2.8 Di VC USD zoom lens, which was set up on a tripod to ensure it would not change position during the test. (Bill Ferris)

Let’s consider the above image set made with the Tamron 70-200mm f/2.8 VC. Due to its smaller sensor, a photograph made with the D90 captures a more narrow angle of view in comparison with an image made with the D610 at the same focal length. To capture an equivalent angle of view at the same distance from the subject, the D610 needs to use a greater focal length. At that increased focal length, the FX format camera will capture an angle of view equivalent to that recorded by the D90.

If both lenses are used at the same f-stop of f/2.8, their respective apertures will be about 46mm for the 130mm, f/2.8 lens on the D90 and 71mm for the 200mm, f/2.8 lens on the D610. Bear in mind, both cameras are at the same distance from the subject. Due to the larger physical aperture of the 200mm focal length lens, it records a shallower depth of field. To match the depth of field of the D90, the D610 is closed down from f/2.8 to f/4. This closes the aperture from 71mm to 50mm, which roughly matches the depth of field recorded by the D90 and its 46mm aperture.

Also, compare the quality of the out of focus background detail in the photos made with the DX format D90 (left most column) with the same detail in the second set of photos made with the FX format D610 (middle of three columns). Pay particular attention to the grouping of four bokeh balls to the left of the lunar lander model. In the D90 photos and in the equivalent D610 photos (right most column), that grouping is well defined with clear separation. In the middle column of D610 photos, that grouping is more diffuse, less well defined and not as clearly separated from the background.

This is what we would expect, considering that all the photos in that collection were made with the cameras and lenses at the same distance from the subject. The first and third column sets of images made with the D610 were made with the same lens aperture as the D90. The third column set of D610 images were made at an equivalent focal length to the D90 images. Both the angle of view and depth of field are equivalent. The first set (left column) of D610 images, while showing a wider angle of view, have equivalent depth of field as the D90 images. Again, this is exactly what one would expect given that the D90, and first and third set of D610 images were made at the same aperture, while the second set (middle column) of D610 photos were made at a larger aperture.

Another approach to producing equivalent depths of field, would have been to increase the lens aperture on the D90. The D90 would need a 130mm f/1.8 lens, which would have a 72mm aperture. That’s very nearly identical to the 71mm aperture of the 200mm, f/2.8 lens on the D610.

If equivalence is your objective, applying the crop factor to the f-stop allows you to calculate the aperture needed to make a photograph having an equivalent depth of field at a focal length delivering an equivalent angle of view. This adjustment can go either way. We can use a larger f-stop (multiply by the crop factor) to close down the aperture of the lens on the larger sensor camera or we can use a smaller f-stop (divide by the crop factor) to open the aperture of the lens on the smaller sensor camera. Either approach will produce equivalent apertures on the two cameras, which allows them to capture matching depths of field.

This is what has led so many photographers to mistakenly conclude that crop sensors significantly alter depth of field. What folks overlook is that the crop factor is applied to allow the lenses on the cameras to operate at the same physical aperture. Again, the key to understanding depth of field is recognizing that distance to subject and lens aperture are the critical factors. If you keep subject distance constant, keeping lens aperture constant will deliver equivalent depth of field. This holds true even if the lenses are used at focal length delivering non-equivalent angles of view.

Wildlife photographers often choose to shoot with crop sensor cameras to effectively bring the animals closer. They want the narrower angle of view delivered by the crop sensor. Shooting at 500mm f/4 with a DX camera will not only produce a larger image of the subject (in comparison with a photograph made using the same lens at the same distance on an FX camera), the DX camera will also record the same shallow depth of field and beautiful, buttery bokeh. That’s a huge advantage and a big reason why crop sensor cameras are so popular with sports and wildlife photographers. Of course, the smaller sensor also captures less total light with each exposure and this has implications for image noise. But that’s another blog entry.

In the meantime, armed with this new information and understanding of the role lens aperture plays in depth of field, let’s get out and shoot.

Bill Ferris | March 2016

Autofocus Fine Tune

Autofocus Fine Tune test shot for Tamron 70-200mm f/2.8 Di VC USD lens at 200mm, f/2.8, ISO 100, 1/200-second with flash and Nikon D610 AF Fine Tune set to OFF (Bill Ferris)

Autofocus fine-tune test shot for Tamron 70-200mm f/2.8 Di VC USD lens at 200mm, f/2.8, ISO 100, 1/200-second with flash. AF fine-tune is turned off. (Bill Ferris)

Choosing the right autofocus (AF) mode can be a real challenge. You could leave the driving to the camera and go with Auto-servo AF (AF-A) mode. If you go that route, don’t expect that dumb box of a camera to make the right choices. It will make choices but they’ll probably not be the same choices you would make.

Being the risk-taker that you are, I’m sure you spend most of your time shooting in either Single-servo (AF-S) or Continuous-servo (AF-C) mode. These allow you greater control and, when good choices are made, a higher success rate making keeper images. Among those choices, is deciding which one or more AF points to use. Do you use one, nine, twenty-one or all the AF points on your camera’s sensor? If just one, do you go with the center point or an outer point? If you choose a group of points, which group? Do you allow the camera to have a say in which AF points are used? So many choices.

Let’s assume you’ve chosen an AF mode, and selected the number and location of the AF points that will be used. The next challenge is to successfully place at least one AF point over your subject and acquire focus. When it all comes together, it’s a beautiful moment. The shutter clicks open and the image swiftly, silently, gets encoded as a collection of 1’s and 0’s on an SD card.

Later, when you look at the photograph in Lightroom and realize it’s still not in focus, that moment of joy becomes frustration. What happened? Why is the eye just ever so slightly soft?

Of all the factors than have the potential to cause an out-of-focus image, arguably the most pernicious is a camera/lens combo that is ever so slightly miscalibrated. Despite your mastery of the camera’s AF system, your successful effort to track the subject and the presence of mind to make an exposure at the decisive moment, that slight miscalibration wreaks havoc. Focus is not set on the eye beneath the AF point. Instead, focus is slightly in front of or just behind the eye. The result is an out of focus image that ends up being deleted rather than marked as a keeper.

Autofocus fine-tune is a tool offered by many professional and high end consumer cameras. It allows you to adjust where focus is set to compensate for a miscalibrated lens. How does it work?

In the above images, the blue shaded portion of the semitransparent square overlay represents an out-of-focus area of the black and white image. The portion of the black and white photo visible within the blue shaded overlay represents the area of the face falling within the focus plane and appearing to be be in focus in the image. TOP: This illustrates a properly focused image. The eyes, brow and mouth fall within the focus plane and appear in-focus. MIDDLE: This represents a back-focused image. The ears an temples are within the focus plane and appear sharp. However, the eyes are above the focus plane and look soft. BOTTOM: This represents a front-focused image. The tip of the nose and chin fall within the focus plane and appear sharp. However, the eyes are behind the focus plane and look soft.

In the above images, the blue shaded portion of the semitransparent square overlay represents an out-of-focus area of the black and white image. The portion of the black and white photo visible within the blue shaded overlay represents the area of the face falling within the focus plane and appearing properly in-focus.
TOP: This illustrates a properly focused image. The eyes, brow and mouth fall within the focus plane and appear in-focus.
MIDDLE: This represents a back-focused image. The ears and temples are within the focus plane and appear sharp. However, the eyes are above the focus plane and look soft.
BOTTOM: This represents a front-focused image. The tip of the nose and chin fall within the focus plane and appear sharp. However, the eyes are behind the focus plane and look soft.

In the above illustration, the focus plane of the camera is represented by the semitransparent, blue square overlay. While all photographs have at least a minimal depth of field, for simplicity, I’m illustrating the focus plane as a two-dimensional, flat zone. With large aperture, small focal ratio lenses being popular for portraiture, the shallow depths of field produced by such lenses leave little margin for error when it comes to achieving accurate focus. If focus is not set on the eye or within a few millimeters of the eye, the resulting image will look “soft” and out-of-focus. There will be portions of the subject’s face that look sharp and in-focus, but if the eyes look soft, the overall impression will be that the photo is soft.

A miscalibrated camera/lens combo may give every indication of making a properly focused exposure. However, despite the fact that the focus point may be directly over the subject’s eye, the camera will set focus slightly in front of or behind the eye. If you are shooting with a fast f-stop, that slight miscalibration can result in unacceptably soft images. Autofocus fine-tune allows you to compensate for this problem.

In the Nikon D610 menu system, AF Fine Tune is found in the Setup Menu. (Bill Ferris)

In the Nikon D610 menu system, AF fine-tune is found in the Setup Menu. (Bill Ferris)

Entering the AF fine-tune menu, the first option is where you select, ON or OFF, for this control. The second setting is the Saved Value for the lens. (Bill Ferris)

Entering the AF fine-tune menu, the first setting allows you to select, ON or OFF. The second setting is the Saved Value for the lens. (Bill Ferris)

Entering the Saved Value setting, select a positive or negative number from +20 to -20. Positive numbers move the focus point farther from the focus plane to compensate for front-focused images. A negative setting moves the focus point closer to the camera focus plane to compensate for back-focused images. (Bill Ferris)

Entering the Saved Value setting, select a positive or negative number from +20 to -20. Positive numbers move the focus point away from the camera to compensate for front-focused images. A negative setting moves the focus point toward the camera to compensate for back-focused images. (Bill Ferris)

Nikon cameras recognize Nikkor lenses and many third party lenses, and are able store AF fine-tune settings for up to 12 different lenses. (Bill Ferris)

Nikon cameras recognize Nikkor lenses and many third party lenses, and are able store AF fine-tune settings for up to 12 different lenses. (Bill Ferris)

The above series of images illustrate how to use AF fine-tune to add an adjustment to compensate for a lens that consistently front-focuses or back-focuses when used with a specific camera body. AF fine-tune settings are not transferable. A setting on one camera may not be needed on a different but same model body. The setting is unique to that specific camera/lens combination.

Also, Nikon bodies do not allow you to define multiple settings for the same lens. For example, when working with a zoom lens, you are limited to one setting for that lens. If AF fine-tune is engaged, the adjustment will be applied regardless of the focal length used. I recommend you test a zoom lens at the focal length at which it will most likely be used.

The below series of images illustrate my approach to testing a lens to determine if an AF fine-tune adjustment is needed. Right click the below images to open a full-size JPEG in a new window.

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF Fine Tune at OFF. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF fine-tune turned off. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF Fine Tune at +2. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF fine-tune at +2. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF Fine Tune at +4. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF Fine Tune at +4. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF Fine Tune at +6. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF fine-tune at +6. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF Fine Tune at +8. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF fine-tune at +8. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF Fine Tune at +10. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF fine-tune at +10. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF Fine Tune at -2. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF fine-tune at -2. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF Fine Tune at -4. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF fine-tune at -4. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF Fine Tune at -6. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF fine-tune at -6. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF Fine Tune at -8. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF fine-tune at -8. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF Fine Tune at -10. (Bill Ferris)

Photo made with Nikon D610 and Tamron 24-70mm f/2.8 Di VC USD lens at 70mm, f/2.8, ISO 100, 1/200-second with flash. AF fine-tune at -10. (Bill Ferris)

The above series of images is a real world test under real world conditions. When shooting portraiture with the D610 and Tamron 24-70 f/2.8 Di VC USD, I typically shoot wide open with a mix of ambient light and flash at 1/200-second. If you’re going to test a lens to determine an appropriate AF fine-tune setting, test the lens under the same conditions in which it will most likely be used.

AF fine-tune is turned off for the first image in the series. The next ten images were taken with AF fine-tune turned on. A +2 adjustment is applied in the second image. Images three through six have adjustments of +4, +6, +8 and +10 applied, respectively. A -2 adjustment has been applied to image seven in the series. The next four images have adjustments of -4, -6, -8 and -10 applied, respectively. At each setting, I took five handheld exposures with vibration compensation (VC) engaged. The above series includes the second exposure in each five-exposure set.

Reviewing the exposures at 1:1 in Lightroom, all five exposures with AF fine-tune turned off were acceptably sharp at the focus point. Two of the five in that set were a bit shallow in focus, displaying minimal in-focus depth of field in front of the focus point. The set which most consistently produced sharp images with good depth of field both in front of and behind the focus point is the set with an adjustment of -6 applied.

Now, it gets complicated. Normally, I would choose the -6 setting for the Tamron 24-70mm f/2.8 VC and leave it at that. However, I also have a Tamron 70-200mm f/2.8 Di VC USD lens but the Nikon firmware does not distinguish between it and the 24-70mm f/2.8 VC. If I leave AF fine-tune turned on with a -6 setting for the 24-70mm f/2.8, the same adjustment will be applied when the 70-200mm f/2.8 is mounted on the D610. So, I’ve also tested the Tamron 70-200mm, using the same approach as with the shorter zoom.

The results of the testing with the Tamron 70-200mm f/2.8 VC were fairly straightforward. The best set of images was taken with AF fine-tune turned off. The set taken with an AF fine-tune adjustment of -6 were among the worst of the lot.

After testing both lenses, I’ve decided to store a -6 adjustment for the Tamron lenses but to leave AF fine-tune turned off. Both lenses make sharp, usable images without an AF fine-tune adjustment. If I remember to activate AF fine-tune when the 24-70 VC is mounted, so much the better.

Now, it’s time to get out and shoot.

Bill Ferris | November 2015

What the f/#?

The Tamron 70-200 f/2.8 Di VC USD zoom lens has a focal ratio of f/2.8. This defines the largest aperture the lens is capable of having at all focal lengths throughout the zoom range. Operating at f/2.8, the focal length selected will be 2.8X the size of the aperture. While the focal length range is 70-200mm, the range of largest apertures is 25mm at a 70mm focal length to 71mm at 200mm focal length.

The Tamron 70-200 f/2.8 Di VC USD zoom lens has a constant focal ratio of f/2.8. This defines the largest aperture the lens will have throughout the zoom range. Operating at f/2.8, the focal length selected will be 2.8X the aperture. With a focal length range of 70-200mm, the widest aperture varies from 25mm at a focal length of 70mm to 71mm at a 200mm focal length. (Bill Ferris)

Let’s nerd out with some tech talk. Let’s chat about focal ratio.

Focal ratio is a rarely seen or heard phrase in online photography blogs and forums, which is surprising when you consider the important role focal ratio plays in photography. Focal ratio describes the size of a lens’s focal length relative to its aperture. It is typically expressed as an f-number, such as f/2.8. Ironically, when photographers start talking about lens aperture, it’s more than likely they’re actually discussing focal ratio. Let’s see if we can sort all this out.

We’ll begin at the beginning. Focal length is typically the first number mentioned when describing a lens. A 50mm lens has a focal length of, wait for it…50mm or roughly two inches. One may be inclined to think focal length is the distance from the front of the lens to the back, but it’s not. Focal length is the distance from the optical center of the lens to the image plane (film or sensor) where the image is formed. The optical center is usually inside the lens and is sometimes referred to as the point of convergence; the point where two light rays converge and cross.

The above diagram shows a cross section of the Nikkor 50mm f/1.4 lens. The focal length of the lens is 50mm, which is measured from the optical center of the lens to the image plane at the sensor.

The above diagram shows a cross section of the Nikkor 50mm f/1.4 lens. The focal length of the lens is 50mm, which is measured from the optical center of the lens to the image plane at the sensor.

Focal length determines how much the image is magnified. This is typically described as the angle of view produced by the lens. A 50mm lens produces a 47° (on a diagonal) angle of view at the image plane of a 35mm camera body. A 24mm lens delivers an 84° angle of view and a 200mm lens presents a 12° angle of view. Since the angle of view produced by a 50mm lens is similar to that of normal vision, it is known in 35mm photography as a normal lens. 24mm is a wide angle focal length and a 200mm is a telephoto lens.

Of course, 35mm is just one of many photographic formats. A photographic format is defined by the physical size of the medium used to record the image. In film photography, 35mm describes the length of the long side of a slide or film negative. Today’s digital cameras use light-sensitive CMOS sensors to record images. In full frame digital cameras, the sensor measures 36mm on the longest side. APS-C digital cameras have sensors that are about 23mm on the longest side. The camera in your smartphone or tablet is probably built around a sensor no larger than about 10 millimeters. What does sensor size have to do with this topic? A lot.

The above diagram illustrates the relative sizes of common digital camera sensor formats. The largest shown is a full frame (FX) sensor. The smallesst (lower left corner) is representaive of a typical smart phone (1/2.3") sensor.

The above diagram illustrates the relative sizes of common digital camera sensor formats. The largest shown is a full frame (35mm equivalent) sensor. The smallest (lower left corner) is representative of a smartphone (1/2.3″) sensor.

The smaller the sensor or film medium, the farther you need to be from your subject to match the field of view delivered by a given focal length lens. Imagine standing 10 feet from your subject with a full-frame DSLR camera and framing your subject head-to-toe using a normal 50mm lens. If you were to mount the same lens on an APS-C camera body, that camera’s smaller sensor would cut off or crop a portion of the image produced by the lens. You would need to step back to a distance of about 15 feet to reproduce the angle of view you had with the full frame camera body.

Another factor to consider when shooting with a “crop sensor” body is the effect of sensor size on depth of field. Depth of field (DOF) is the range of distances – nearest to farthest – in an image that appear acceptably sharp and in-focus. DOF is determined by magnification (lens focal length) and by the lens focal ratio or f-number. In a nutshell, bringing the subject closer decreases depth of field. Moving the subject farther away increases depth of field. As depth of field increases, a deeper portion of the image appears in focus. As depth of field decreases, only a narrow or shallow range looks sharp and in focus.

Both photographs were made using a Nikon D610 with Tamron 70-200 Di VC USD zoom lens at 125mm. The image on the left was shot at f/2.8 and has a much shallower depth of field. The image on the right was shot at f/32 and presents a much wider depth of field.

The above photographs were made using a Nikon D610 and Tamron 70-200mm f/2.8 Di VC USD zoom lens at 125mm. The image on the left was shot at f/2.8 and has a much shallower depth of field. The image on the right was shot at f/32 and shows much more of the field in focus.

As mentioned, focal ratio also has an effect on depth of field. For any given focal length, increasing focal ratio (making the f-number larger) increases depth of field while decreasing focal ratio (making the f-number smaller) reduces depth of field. We’ve already discussed the cropping effect of shooting with a smaller sensor. Stepping back to reproduce a desired angle of view increases depth of field. Zooming or changing lenses to shoot with a shorter focal length (to match the field of view provided by a full frame sensor body) increases depth of field.

One can compensate for the increased depth of field which results from the adjustments commonly made to expand the angle of view delivered by a crop sensor camera by shooting with smaller f-numbers. For example, shooting with a 35mm lens at f/1.4 will allow an APS-C sensor body to produce photographs having the same framing and depth of field as images made from the same position using a 50mm f/2.0 lens on a full frame body.

Let’s explore this in a bit more detail. Suppose you’re shooting with two cameras, one full frame and the other a crop sensor, and using the same 50mm lens with both. Its effective focal length (the focal length matching the angle of view delivered to the sensor) will be 50% longer or 75mm on the APS-C body. At f/4, the 50mm lens will have an aperture of 12.5mm. If we step back to compensate for the more narrow angle of view, the effective focal ratio (the focal ratio delivering an equivalent depth of field from the distance at which this lens matches the angle of view delivered to a full frame camera) will be f/6. Its effective 75mm focal length divided by the 12.5mm aperture equals six.

Do you see the relationship? We’re using an f/4 lens on an APS-C body. When the goal is to match the angle of view and depth of field produced by a full frame camera, we can determine the effective focal ratio at which a crop sensor camera needs to operate by dividing the focal ratio of the lens by the crop factor. The crop factor is 1.5 and the effective focal ratio (for depth of field) is f/6.

Here’s an illustration.

These images illustrate how to use a crop sensor camera to match both the angle of view and the depth of field delivered by a full frame body. I used a Nikon D610 and Nikon D90 to make photographs of the same toy caboose. Both cameras used a Tamron 70-200 f/2.8 Di VC USD lens. The lens was mounted on a tripod and the bodies switched out to ensure the lens would not move from its position during the test. The D610 uses a 36mm sensor and shot at 105mm, f/4 to make both images. The D90 uses an APS-C sensor with a 1.5X crop factor. I shot at 75mm, f/4 to make the first image. Comparing the first (top) images, we see that the D90 delivered a similar angle of view as the D610 but a comparison of the background shows the D610 to have a more shallow depth of field. The background in the D90 image is just skosh nearer to being in focus. For the second image, I applied the conversion factor and shot with the D90 at 70mm, f/2.8. A comparison of this image with the D610 image shows both to have delivered similar angles of view and similar depth of field. (Bill Ferris)

These images illustrate how to use a crop sensor camera to match both the angle of view and the depth of field delivered by a full frame body. I used a Nikon D610 and Nikon D90 to make photographs of the same toy caboose. Both cameras used the same Tamron 70-200 f/2.8 Di VC USD lens. The lens was mounted on a tripod and the bodies switched out to ensure the lens would not move from its position during the test. The D610 is built around a 36mm sensor and was used at 105mm, f/4 to make both images. The D90 has an APS-C sensor with a 1.5X crop factor. I shot at 70mm, f/4 to make the first image. Comparing the first (top) images, we see that the D90 delivered a similar angle of view as the D610 but a comparison of background detail reveals the D610 to have a more shallow depth of field. The background in the D90 image is just a skosh nearer to being in focus. For the second image, I applied the conversion factor and shot with the D90 at 70mm, f/2.8. A comparison of this image with the D610 image shows both to have delivered similar angles of view and similar depth of field. (Bill Ferris)

So, we’ve demonstrated that, in comparison with full frame cameras, crop sensor camera bodies produce images having narrower angles of view and, when adjustments are made to compensate for this, increased depth of field. We’ve also demonstrated that you can compensate for these performance factors. Either increase the distance between you and the subject or use a shorter focal length to increase the angle of view. Shoot at a smaller focal ratio (f-number) to make the depth of field more shallow. Next, we’ll explore the relationship between sensor size and length of exposure. Here’s a heads up, the outcome may not be what you expect.

I used my Nikon D610 (full frame) and Nikon D90 (APS-C) to take a series of exposures of a toy train engine. The toy steam engine was set up outside on a small tray table. The sky was overcast with nice, even lighting throughout the test. Both bodies used the same Tamron 70-200mm f/2.8 Di VC USD lens, which was set at 70mm. I selected ISO 200 on both cameras for all exposures. The zoom lens was set up on a tripod and the camera bodies were switched out without changing the position of the lens. I used each camera to make exposures at f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22 and f/32. I shot in aperture priority on both cameras and let their internal brains select the proper exposure.

Below, are pairs of images showing the photographs made at the same settings with the two bodies, side-by-side. All are unedited JPEGs. Keep in mind that the sensor in the D90 body cropped the image to match the angle of view produced by a 105mm lens.

In this comparison, photographs of the same subject made with a Nikon D610 (left) and a Nikon D90 (right) are shown, side-by-side. Both cameras shot at ISO 200. Both cameras used the same Tamron lens at 70mm. The lens was mounted on a tripod to ensure it would remain in the same position throughout the test. For each focal ratio, both cameras used the same exposure. (Bill Ferris)

In this comparison, photographs of the same subject made with Nikon D610 (left) and Nikon D90 (right) cameras are shown, side-by-side. Both cameras were set to ISO 200. Both cameras used the same Tamron lens at 70mm. The lens was mounted on a tripod to ensure it would remain in the same position throughout the test. At each focal ratio, both cameras metered the scene as having the same brightness and chose the same exposure. (Bill Ferris)

Let’s talk more about this f-number thing. You’ll recall that focal ratio describes the ratio of the focal length of the lens to the aperture of the lens. A 50mm lens at f/2.0 has a focal length that is 2-times its aperture. Therefore, the lens aperture at f/2.0 will be 25mm. At f/4.0, the aperture is 12.5mm; at f/8.0, 6.25mm and so on. The relationship between aperture and focal ratio is pretty straight forward: for any given focal length, decreasing aperture increases focal ratio and increasing aperture decreases focal ratio.

Rarely, however, do photographers talk about the f-number as a focal ratio. More commonly, they talk about it as a lens aperture. They talk about an f/2.0 lens having a larger aperture than an f/4.0 lens. It’s an accurate statement, if we’re talking about the same lens at different focal ratios. But this is just one of many scenarios where focal ratios are compared.

Let’s consider the scenario of discussing different lenses. Suppose we’re comparing a 50mm lens to a 100mm lens. Suppose the 50mm lens is being used at f/2 and the 100mm lens is set to f/4. One might think the 50mm lens, by virtue of having a smaller f-number, will have a larger aperture. In fact, both lenses have identical 25mm apertures. It simply isn’t the case that every f/1.4 lens has a larger aperture than every f/8 lens. In reality, it is quite common for a lens operating at a large f-number to have a larger aperture than a lens working at a small f-number. I would wager to guess that there isn’t a focal ratio at which a 600mm lens doesn’t have a larger aperture than the fastest focal ratio smartphone.

One quality that does translate across different lenses and cameras, is the speed of the imaging system. What does speed have to do with photography? To understand, it helps to think of a properly exposed photograph as one where a certain intensity of light needs to fall upon the sensor at the image plane. Think of light as water, the sensor as a container used to collect water (light) and the lens as the opening through which water is poured into the container.

That said – and this next point is critical – a properly exposed image is not determined by the total quantity of light delivered to the sensor. The length of a proper exposure is determined by the average brightness of the image falling on the sensor. To better understand this, we’re going to introduce a new concept: surface brightness.

The above illustrates the concept of Surface Brightness in photography. For a properly exposed image, the camera's optical system must collect and deliver light having a surface brightness (brightness or intensity per square millimeter) to the sensor. This is represented by the evenly deep layer of "blue" light collected bu the sensor. If you use the same lens on a crop sensor body, the same intensity of light (represented by the central red region) is delivered to the sensor. Being smaller, the crop sensor collects less total light. However, the surface brightness of the image (the brightness per square millimeter) is identical to that of the larger sensor. (Bill Ferris)

The above illustrates the concept of Surface Brightness in photography. For a properly exposed image, the camera’s optical system must collect and deliver light having a surface brightness (brightness per square millimeter) to the sensor. This is represented by the thick layer of “blue” light collected by the sensor. The thickness of the layer represents the intensity or average brightness of the image. If we use the same lens on a crop sensor body, the same intensity (thickness) of light is delivered to the sensor. This is represented by the central red zone on the sensor. Being smaller, the crop sensor collects less total light. However, the surface brightness of the image is identical to that of the larger sensor. (Bill Ferris)

Earlier, a correct exposure was described as one where a container (sensor) is filled to the correct depth (intensity) with water (light). It doesn’t matter if the container is large enough to hold one gallon or 100 gallons. As long as it’s filled to the proper depth, the exposure will be good. In this example, the depth of the water represents the average brightness of the image at the image plane. Another way to describe the average brightness or intensity of light, is to talk about image surface brightness.

Surface brightness is defined as a brightness per unit area. In photography, we can define surface brightness as the brightness of light per square millimeter falling on the film or sensor. It is not a total volume or quantity of light. Rather, it is an average intensity of light. Surface brightness is strictly determined by the focal ratio of the optical system. The lens f-number determines the length of the exposure needed to deliver light of a certain intensity to the sensor. A full frame camera, crop sensor camera and smartphone camera focused on the same subject – and all operating at f/2.0 – will deliver the same light intensity per square millimeter (the same surface brightness) to their respective sensors during the same length exposure.

The relative sizes of full frame (pink) and APS-C (blue) sensors is illustrated above. The effects of a crop frame sensor include an increase in effective focal length and an increase in effective depth of field.

The relative sizes of full frame (pink) and APS-C (blue) sensors is illustrated above. The effects of a crop frame sensor include an increase in effective focal length and effective depth of field.

Despite the fact that a crop sensor doesn’t collect as much total light during an exposure as a full frame sensor, the intensity or surface brightness of the images formed on both sensors will be the same. We saw this at work in the above illustrations comparing exposures made with the D610 and D90. Despite the fact that, during each set of exposures, the D90’s smaller sensor collected less total light than the full frame sensor of the D610, the image made by the D90 was still properly exposed. This is because the exposures made by both cameras produced images having identical surface brightness at the image plane.

This set of images compares performance between crop sensor and full frame DSLR bodies. The images in the left column were made with a Nikon D90. Images in the right three columns were made with a Nikon D610. Both cameras used the same Tamron 70-200mm f/2.8 Di VC USD zoom lens, which was set up on a tripod to ensure it would not change position during the test. Both cameras used ISO 200, center point average metering and were operated in Aperture Priority. The subject in these photos is a scale model of the Lunar Excursion Module (LEM) from the Apollo program.

This set of images compares performance between crop sensor and full frame DSLR bodies. The images in the left column were made with a Nikon D90. Images in the right three columns were made with a Nikon D610. Both cameras used the same Tamron 70-200mm f/2.8 Di VC USD zoom lens, which was set up on a tripod to ensure it would not change position during the test. Both cameras used ISO 200, center point average metering and were operated in Aperture Priority. The subject in these photos is a scale model of the Lunar Excursion Module (LEM) from the Apollo program.

The above illustration allows us to compare the performance of crop sensor and full frame cameras. The first column of D610 exposures matches the settings of the D90 images in the left-most column. Focal length and focal ratio are the same. In most cases, both cameras’ metering systems selected the same exposure. The most obvious difference between the D90 and first set of D610 images is the wider angle of view delivered by the full frame sensor. For the second set of D610 images, I zoomed in to match the effective focal length of the D90. The angles of view of these images closely match the corresponding D90 exposures. The second set of D610 images were shot at f/2.8 and clearly display a more shallow depth of field. For the third set of D610 photographs, I changed the focal ratio to match the depth of field presented in the D90 images. Notice that the exposures for these images are all 1/800-second. They’re longer to compensate for the larger focal ratio.

Focal Ratio is the key to understanding how different cameras, lenses and sensors are able to make good photographs using the same or similar length exposures. Focal ratio determines the length of time needed to collect enough light to make an image having the required surface brightness. For any two cameras operating at the same ISO and delivering the same angle of view, the exposure times will typically be the same.

So, the next time you read or hear a photographer talking about an f/1.4 lens having a larger aperture than an f/2.0 lens, stop and give that statement some thought. If the lenses being compared are a 20mm f/1.4 and a 50mm f/2.0, the 50mm lens will be operating with a larger aperture. The 50mm lens will have a 25mm aperture at f/2.0 and the 20mm, f/1.4 lens aperture will be just over 14mm. However, due to its faster focal ratio, the 20mm lens will deliver more light per square millimeter to the sensor, faster. Because the f/1.4 lens produces a brighter image – an image having a higher surface brightness – the length of the exposure will be shorter.

In photography, the objective is not to deliver the largest volume of light to the sensor. The objective is to deliver the needed intensity (surface brightness) of light to the sensor. Speed is everything and focal ratio is the key.

Now, get out there and shoot!

Bill Ferris | August 2015

Camera Settings – Landscape Photography

It is April and spring has arrived at Monument Valley along the Arizona/Utah border. The pastel glow of twilight dyes the valley a cool hue while warm light from a setting Sun catches the wispy overhead clouds. (Bill Ferris)

It is April and spring has arrived at Monument Valley along the Arizona/Utah border. The pastel glow of twilight dyes the valley a cool hue while warm light from a setting Sun catches the wispy overhead clouds. (Bill Ferris)

There have been more than a few days when I’ve wondered if I travel to do photography or if the camera is just an excuse to get outside amidst inspiring landscapes. Actually, there is no wondering about it. It’s the latter. I have a deep, soulful connection to nature. Truth be told, if faced with the choice of spending my remaining years alone in a magnificent wilderness or amongst the beehive of activity in a major city, I might choose the wild.

It should come as no surprise, then, that landscape imaging is my first love in photographry. Since a move from the Midwest to northern Arizona nearly 20 years ago, I’ve been blessed to have ready access to some of the most dramatic and iconic landscapes of the American West. Grand Canyon, Monument Valley,  Arches, Canyonlands – these are nature’s cathedrals. These are the places where I hone my craft and renew a spiritual connection with the world.

This blog continues the series in which I share the camera settings I use for specific genres of photography. Today’s genre is landscapes and these are the settings:

  • Mode: Aperture Priority
  • Aperture:  f/13 to f/22
  • ISO: 100 to 200
  • Image Format: RAW
  • Focus: Back Button or Live View
  • Shutter Release: Timed with a 5-second delay
  • Essential Gear: Tripod
Late day light paints Zoroaster Temple in Grand Canyon a deep amber hue as seen from a campsite along Clear Creek Trail. (Bill Ferris)

Late day light paints Zoroaster Temple in Grand Canyon a deep amber hue as seen from a campsite along Clear Creek Trail. (Bill Ferris)

Great light is the first element of a great landscape. While it is absolutely possible to make a fantastic landscape exposure in midday light, the golden hour times of sunrise and sunset are the most prized. The soft earthy glow adds a dramatic feel and reveals the inner beauty of a place. Weather, is the second key element. Clouds, rain and lightning put passion on display. Snow reveals the essence of a place and hints at possibilities to come.

A common theme connecting the above, is the relatively low light levels one encounters when shooting under such conditions. Unlike other genres (e.g. sports, wildlife and portraiture), short exposures and shallow depths of field are not necessarily desirable when shooting landscapes. More typically, you want great depth of field. Also, since your subject is mostly static, exposure times can be longer without compromising image sharpness.

An f/13 to f/22 aperture will deliver an in-focus, sharp image through the fore-, mid- and backgrounds. (APS-C bodies can achieve the same at f/9 to f/16.) With depth of field being so critical to achieving the desired result, I usually shoot in Aperture Priority mode and dial in an aperture – more accurately, a focal ratio – of f/13. Depending on the lighting and composition, I’ll go as large (in focal ratio) as f/22 or more.

Of course, I always shoot in RAW to allow as much latitude as possible during processing.

White House ruin in Canyon de Chelly National Monument (Chinle, Arizona) (Bill Ferris)

White House ruin in Canyon de Chelly National Monument (Chinle, Arizona) (Bill Ferris)

To maximize image quality and minimize noise, I typically use the base ISO of the camera body. In the case of the Nikon D610, the base ISO is 100. This combination of low light, small aperture and low ISO forces the camera to use relatively slow shutter speeds to make a properly exposed image. When shooting just before sunrise or shortly after sunset, an exposure of 1-second or longer may be needed.

Long exposures demand a solid, stable platform to ensure good sharpness in the resulting image. This makes a tripod essential gear for the landscape photographer. I use a Benro model tripod. It is designed to be lightweight and portable, while still providing good stability. It is not as rock solid as other beefier designs, which means I’m always in need of a sheltered location when doing photography in a strong wind.

A technique I use to minimize vibration, is setting a 5-second delay on the shutter release. This allows any vibration introduced when I push the shutter release to dampen before the exposure begins. I also use either back button focus or contrast detection focus in Live View to help ensure best focus. Contrast detection, while slower, is sometimes a bit more accurate than phase detection. Moving focus control off the shutter release button minimizes the risk of a last second focus change when an exposure is made.

Using these settings, allows me to take full advantage of the spectacular landscapes populating the Desert  Southwest. If you are a landscape enthusiast, I hope you find they help your results, as well.

So, get out there and shoot.

Bill Ferris | April 2015

Camera Settings – Wildlife Photography

An American White Ibis preens in the late afternoon light at Disney World Epcot theme park. (Bill Ferris)

An American White Ibis preens in the late afternoon light at Disney World Epcot theme park. (Bill Ferris)

This post continues a series on camera settings for specific genres of photography. As I mentioned in the first installment, I am not suggesting these settings will be best for every photographer. I am sharing them because they work for me and may be of some help to you.

As the above image indicates, this post will focus on settings for bird and wildlife photography. Let’s begin with my goals when shooting animals in a natural setting:

  • Communicate the wild
  • Convey the personality of the animal
  • Bring the viewer close

There is something about an animal in a wilderness setting that captures the imagination. This is particularly true in cultures that feel a strong connection to a past when people lived, struggled, thrived and died in wilderness places. They competed not only with the land and weather but also with animals. Some animals were hunted as sources of food and clothing. Others were hunted as competitors for scarce food resources or as threats to people.

A photograph of an animal in a wilderness setting has the potential to reconnect us with that pioneer heritage. It can make the pulse quicken and loose a surge of adrenalin in the blood. Communicating the wild is as much about setting as the animal, itself. Framing the shot with a rugged terrain or severe weather conveys a sense of wilderness. The personality of the animal comes to life through action. Interesting – even aggressive – behavior does the trick. Sometimes, the suggestion of a behavior that is about to happen can be even more compelling. Capturing the instant before the animal becomes aggressive hints at wildness and allows the audience’s imagination to fill in the rest.

The Kilimanjaro Safaris tour at Disney World Animal Kingdom exposes visitors to a host of animals native to Africa, including the giraffe. (Bill Ferris)

The Kilimanjaro Safaris tour at Disney World Animal Kingdom exposes visitors to a host of animals native to Africa, including the giraffe. (Bill Ferris)

A long telephoto lens can bring the viewer close enough to feel the breath of the animal. Stealth and patience, when skillfully employed, can have the same effect. Every guideline has its exceptions and this one is no different. A wide angle lens capturing the interesting behavior of a collection of animals in the wild can be just as inspiring.

Bird and wildlife photography is a relatively new interest for me. I’m still searching for that heart-stopping image of an apex predator in the wild, or an iconic creature persevering against nature’s maelstrom. However, the technique of capturing such moments is fairly well ingrained. I’ll be ready when the moment arrives. Here, are my settings:

  • Aperture: f/2.8 to f/5.6
  • ISO: ISO-auto with 1/500 to 1/1000-second as minimum shutter speed and 6400 as maximum ISO
  • Back Button Focus: AE-L/AF-L button assigned to autofocus control
  • Burst Rate: Low (3 fps) to Continuous High (6 fps)
  • Image Quality: RAW
  • Exposure Compensation:  +2/3 to 0 to -2/3 stop

I use a large aperture to blur the background and isolate the subject. A wide open aperture also allows for the use of more reasonable ISO’s when shooting early in the day. Now, an aperture closed one stop from wide open will do a better job of capturing pin sharp detail in the animal. So, if the light level will allow it and if there is significant distance between your subject and the background, consider closing down the lens a bit.

Back button focus is a great technique for just about any type of photography. It gives you more control over focus point and framing. If the animal is moving slowly, a shutter speed of 1/500-second will do an excellent job of freezing action. However, birds in flight and other more aggressive actions demand a faster shutter speed. A low burst rate works fine for an animal slowly grazing for food. A faster burst rate is called for when shooting birds in flight and other more dynamic action.

A bull Elk eyes a gathering crowd of tourists on the South Rim of Grand Canyon National Park. (Bill Ferris)

A bull elk eyes a gathering crowd of tourists on the South Rim of Grand Canyon National Park. (Bill Ferris)

Finally, you’ll want to pay attention to the coloration of an animal. Animals with dark fur may require an exposure compensation of +2/3 stop to preserve detail. By contrast, compensation of -2/3 stop will preserve feather detail when photographing a bright white bird.

These are the settings I use when photographing birds and animals. If you give them a try, I think you’ll find the results rewarding. At the very least, you’ll gain a better understanding of the settings that work best for you.

Now, get out there and shoot!

Bill Ferris | April 2015

Camera Settings – Sports Photography

NAU's Eddie Horn grabs a handful of facemask to prevent Eastern Washington's Quincy Forte from reaching the end zone

NAU’s Eddie Horn grabs a handful of facemask to prevent Eastern Washington’s Quincy Forte from reaching the end zone (Bill Ferris)

With this post, I’m launching a series in which I will share the settings I use for specific genres of photography. Each article will focus on one kind of photographry: landscape, wildlife, event, portraiture and, in this entry, sports.

Right off the top, I want to be clear about something. The settings I use are not necessarily best for everyone. In fact, I suspect the opposite may be closer to the truth. Many professional and experienced amateur photographers prefer to shoot in full manual mode. I don’t.

In any given situation, there are some settings I absolutely want to control and others I’m perfectly comfortable allowing the camera to control. It’s been my experience that modern digital cameras are reliably competent at choosing settings like shutter speed and ISO. Even if the setting the camera chooses is off by 1/3 to 1/2 a stop, shooting in RAW allows me to correct for that in post with just a few clicks of the mouse.

In short, the settings I use work for me and my workflow. My intent in sharing them in this series is that they may help you to make better photos and get more satisfaction from photography.

So, let’s get to it. Here, are the  settings I typically use with my Nikon D610 when shooting sports:

  • Mode: Aperture Priority
  • Aperture: f/2.8
  • ISO: ISO-auto with 1/1000-second as minimum shutter speed and 6400 as maximum ISO
  • Autofocus: Continuous with a 9-point cluster at the center
  • Back Button Focus: AE-L/AF-L button assigned to autofocus control
  • Burst Rate: Continuous High (6 fps)
  • Image Quality: RAW

Why? Let’s start at the beginning. Before I start shooting, I give some thought to what I want to accomplish with the photograph. Here are my goals for sports photography:

  • Capture the decisive moment
  • Communicate the emotion of that moment
  • Put the audience in the middle of the action

The above settings allow me to accomplish all three.

A goalkeeper prepares to send the ball out of her zone.

A goalkeeper prepares to send the ball out of her zone. (Bill Ferris)

The first decision I make when setting up the camera is selecting a mode to use. I never shoot in full Auto. In that mode, the camera makes all the decisions and I’ve yet to find a camera having an aesthetic identical to mine. I rarely shoot in Manual. In that mode, I make all the decisions and, frankly, that’s just a lot of work.

Aperture Priority allows me to lock in a focal ratio. Normally, I’ll set the lens to f/2.8. Since I’ll be using a fast shutter speed to freeze action, I need to deliver big heaping gobs of light to the sensor to produce a properly exposed image. Shooting at f/2.8 maximizes the light collected by the lens and delivered to the sensor, at any given moment.

A large aperture also produces an image with a shallow depth of field. That is a huge plus when shooting sports. Often, the shot is focused on one player, coach or person. But how to draw attention to someone who is surrounded by a melee of athletes, officials and fans? A shallow depth of field serves to isolate the subject by putting everything and everyone else out of focus.

With a wide aperture selected and locked in, the next choice is which shutter speed to use. For basketball, soccer and football, I have found a shutter speed of 1/1000-second does a great job of freezing the action. Now, I could do this by putting the camera in manual mode, selecting the aperture (f/2.8), shutter speed (1/1000-second) and ISO. But I’m lazy. I don’t want to be responsible for all three variables. I want the camera to do some of the work. I’ll choose the aperture and shutter speed, and let the camera choose the ISO.

This is why I use Nikon’s Auto-ISO setting. In this setting, you choose a minimum shutter speed and a maximum ISO. For sports, I select 1/1000-second and a maximum ISO of 6400. Shooting with the D610, I’ve been very pleased with the quality of images taken at ISO 6400

At this point, I’m almost ready to start shooting.

This photograph was taken with a Tamron 70-200mm at 135mm, f/2.8, ISO 3600, 1/640-second

This photograph was taken with a Tamron 70-200mm at 135mm, f/2.8, ISO 3600, 1/640-second (Bill Ferris)

Next, i check the image quality setting to confirm it’s still in RAW. Shooting in RAW serves several purposes. First, it is the format that captures and preserves the most information about each image. The more information there is at my disposal, the greater the flexibility I have in post. RAW allows for adjustments to be easily made in Lightroom, not just in exposure, but also in white balance, contrast and a host of other key settings. As such, shooting in RAW gives me the greatest latitude when processing an exposure. And since I’m trusting my camera to choose the ISO, RAW acts as my insurance policy against a setting that is off by as much as a full stop. Typically, however, the Nikon D610 is within 1/3-stop in the ISO it chooses.

To ensure that my photographs are properly focused, I use Nikon’s AF-C or continuous autofocus mode. In this mode, the camera continuously adjusts focus to keep the subject sharp, For most events, I’ll use a cluster of nine autofocus points – sometimes, a single point – to allow the camera to focus on the subject while ignoring distracting objects within the frame. The autofocus points at the center of the frame are most accurate. Hence my preference for a central grouping.

Now, to give myself more control over when and where focus is set, I also engage back button focus. This is a technique where you assign focus control to a button on the back of the camera body. I assign focus control to the AE-L/AF-L button on my Nikon D610. With back button focus engaged, I am able to push the AE-L/AF-L button when I want to set focus. If I’m shooting a stationary subject, I can set focus then remove my finger from the button and recompose. If the subject is moving, I’ll continue pressing the button and allow the camera to follow focus while I’m keeping the subject framed.

With 12-seconds left in regulation, NAU's Dan Galindo hauls in a Jordan Perry pass to score the game-winning touchdown

With 12-seconds left in regulation, NAU’s Dan Galindo hauls in a Jordan Perry pass to score the game-winning touchdown. (Bill Ferris)

Almost by definition, athletes are quick and fast-moving subjects. As such, I use my camera’s highest burst rate to rip 6-10 exposures in a 1-2 second burst. This gives me the best chance of capturing the decisive moment. The only thing that’s missing from the above photo, is the official’s arms in the air signaling a touchdown. But that didn’t happen until long after the receiver made the catch.

While we’re on the subject of moments, let’s address a setting that, all too often, is ignored. Moments are fleeting. As soon as you recognize one as being of significance, it is already gone. One of the keys to successful sports photography is anticipating a decisive moment, recognizing that it is about to happen. This has more to do with you, as a student of the game, than with your camera settings. Know the sport. Decide ahead of time the kind of moment you want (a score, a collision, the joy of victory, dignity in defeat), watch for that moment, recognize when it is about to happen and press the shutter release.

Now, get out there and shoot.

Bill Ferris | January 2015

Shallow

A lone juniper tree clings to life on a stony outcrop overlooking Grand Canyon. (Lipan Point, South Rim) (Bill Ferris)

A lone juniper tree clings to life on a stony outcrop overlooking Grand Canyon. This photograph was made with a Nikon D610, Tamron 24-70 mm, f/2.8 VC lens at 60 mm, f/2.8, ISO 100, 1/800-second. (Lipan Point, South Rim) (Bill Ferris)

Depth of field is as important to photography as lighting and composition. Normally when doing landscape photography, I use focal ratios in the f/9 to f/16 range. Large focal ratios deliver images with great depth of field where objects in the fore-, mid- and background are all in focus. On a recent trip to the South Rim of Grand Canyon, I decided to experiment with using shallow depth of field and the above photograph is the result.

I was at Lipan Point, one of my favorite overlooks on the South Rim. From Lipan Point, you are treated to a fine view of Desert View and Palisades of the Desert to the east, and of Wotans Throne and Angels Gate to the west. I followed a social trail from the parking lot to a stone outcrop offering an unobstructed view of the canyon. Even on days when the light isn’t good for photography, the view from this little perch is still worth the 90-minute drive. In the truest sense of the phrase, the view from this vantage point is awe-inspiring.

The sun was low in the southwest sky and painted the surrounding landscape with a slightly warm hue. A small juniper tree clinging to its perch atop the Kaibab limestone was bathed in a wonderful rim light. As I set up my tripod and Nikon D610 to frame the shot, it occurred to me that this photograph should be a portrait of the tenacious tree.

In portraiture, wide open apertures and the associated small focal ratios produce shallow depths of field. This blurs everything not in the focal plane and helps to create separation between the subject, and anything in the foreground or background.

For the above portrait, I used the Tamron 24-70 mm, f/2.8 VC lens. I chose a composition that would include the distant South Rim, inner canyon temples and buttes, a short section of the Colorado River and the creamy late-day light streaming into Grand Canyon. This context clearly identifies the location of the portrait as being Grand Canyon. blurring the background allows the tiny juniper tree to be the subject of the photograph, the star of the show so to speak.

The tenacity of life in a desert environment is on full display, here. The tree clings to a rocky outcrop, a place where you might think a plant would have no chance of survival. But life is determined and defiant in such places. Water can pool in the small rough divots atop the limestone. And where water collects, life is almost always found.

The next time you head out with your camera, why not try something you don’t normally do? If you usually shoot with long focal lengths, try using a wide angle lens. If you often shoot with wide open apertures, make it a point to use a small aperture. Wherever your comfort zone may be, step outside it and try something new.

Now, get out there and shoot.

Bill Ferris | December 2014