Tag Archives: test

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

Vibration Compensation

AFP sign photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/8 with Vibration Compensation engaged.

AFP sign photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/8 with Vibration Compensation engaged. (B. Ferris)

In the Nikon universe, it is referred to as vibration reduction. In Canon parlance, it is called image stabilization. In other worlds, it is referred to as vibration compensation. However you say it, the ability of modern lenses and cameras to compensate for the inherent shakiness of hand-holding your camera to make a photograph has been a significant and positive development in the art form of digital imaging.

To take a closer look at and better understand vibration compensation technology, I decided to set up a test. I used my Nikon D610 camera and a Tamron 70-200 Di VC USD zoom lens to make a series of photographs. The photographs ranged in exposure length from 1/25-second to 1/4000-second. I made at least two exposures at each length, one with the Tamron lens’s vibration compensation engaged and active, and the other with vibration compensation disengaged. For exposures between 1/100-second and 1/2000-second, I made two sets of exposures with VC engaged and disengaged.

I chose a yard sign as the photo subject. The sign features bold lettering against an off-white plastic surface. I set  up the sign in my garage in the shade so it would be illuminated by a soft, even and constant light level. I then set up a folding camp chair in the driveway about six feet from the sign. With the Tamron lens set to 200mm, I began making exposures.

I used the camera’s auto ISO setting to make the exposures from 1/100-second to 1/2000-second, first. With the D610 in aperture priority, I would set the minimum shutter speed at the desired exposure length. Then, I would adjust aperture until the camera would select an ISO that would produce an exposure of the desired length. The D610 will not make an exposure shorter than 1/2000-second in auto ISO so, I put the camera in manual mode to make the exposures at 1/4000-second. Here, are the settings used to make each shot:

  • 1/25-second: Two exposures, one with VC on and the other with VC off. Both at ISO 100, f/25
  • 1/40-second: Two exposures, one with VC on and the other with VC off. Both at ISO 110, f/20
  • 1/100-second: Four exposures, two with VC on and two with VC off. Two at ISO 125, f/11. Two at ISO 100, f/11
  • 1/200-second: Four exposures, two with VC on and two with VC off. Two at ISO 125, f/8. One at ISO 200, f/11. One at ISO 220, f/11
  • 1/400-second: Four exposures, two with VC on and two with VC off. Two at ISO 250, f/8. One at ISO 160, f8. One at ISO 100, f/8
  • 1/800-second: Four exposures, two with VC on and two with VC off. Two at ISO 250, f/5.6. One at ISO 140, f/5.6. One at ISO 110, f/5.6
  • 1/1000-second: Four exposures, two with VC on and two with VC off. Two at ISO 320, f/5.6. One at ISO 160, f/5.6. One at ISO 120, f/5.6
  • 1/1250-second: Four exposures, two with VC on and two with VC off. Two at ISO 400, f/5.6. Two at ISO 200, f/5.6.
  • 1/1600-second: Four exposures, two with VC on and two with VC off. Two at ISO 500, f/5.6. One at ISO 220, f/5.6. One at ISO 250, f/5.6
  • 1/2000-second: Four exposures, two with VC on and two with VC off. Two at ISO 640, f/5.6. One at ISO 280, f/5.6. One at ISO 320, f/5.6
  • 1/4000-second: Two exposures, one with VC on and the other with VC off. One at ISO 640, f/5.6. One at ISO 500, f/5.6

I performed the test for several reasons. One, was to see for myself the extent to which vibration compensation delivers sharper, more detailed images than those made with without VC. Also, I wanted to test a couple of assertions made by photographers who don’t use vibration compensation when shooting at fast exposure rates – 1/1000 to 1/1600 or faster. The usual thinking is that VC offers no benefits at such fast exposures. Some even claim that VC introduces blur when engaged at fast exposure rates.

The results of the above test do not support either claim, not in the least. At all exposures, the images made with vibration compensation turned on appeared sharper and more detailed than those made with VC disabled. Even the VC-engaged image made at 1/4000-second was noticeably sharper than the strictly handheld image made at the same rate. Below, are 100% crops of several exposures. They are JPEG conversions from unprocessed RAW files:

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/8, ISO 125, 1/200 with Vibration Compensation engaged.

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/8, ISO 125, 1/200 with Vibration Compensation engaged.

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/8, ISO 125, 1/200 with Vibration Compensation off.

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/8, ISO 125, 1/200 with Vibration Compensation off.

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/5.6, ISO 160, 1/1000 with Vibration Compensation engaged.

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/5.6, ISO 160, 1/1000 with Vibration Compensation engaged.

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/5.6, ISO 140, 1/1000 with Vibration Compensation off.

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/5.6, ISO 140, 1/1000 with Vibration Compensation off.

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/5.6, ISO 280, 1/2000 with Vibration Compensation engaged.

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/5.6, ISO 280, 1/2000 with Vibration Compensation engaged.

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/5.6, ISO 320, 1/2000 with Vibration Compensation off.

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/5.6, ISO 320, 1/2000 with Vibration Compensation off.

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/5.6, ISO 640, 1/4000 with Vibration Compensation engaged.

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/5.6, ISO 640, 1/4000 with Vibration Compensation engaged.

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/5.6, ISO 500, 1/4000 with Vibration Compensation off.

Photographed with Nikon D610 and Tamron 70-200 Di VC USD zoom lens at 200mm, f/5.6, ISO 500, 1/4000 with Vibration Compensation off.

Based on the results from this test, I am persuaded to keep vibration compensation engaged whenever shooting handheld and regardless of the length of the exposure. Doing so will not introduce blur or distortion and will probably result in a sharper, more detailed photograph.

But don’t take my word for it. See for yourself. Get out and shoot.

Bill Ferris | October 2014