M, Is for Manual

This single exposure was shot at sunset from a vantage point below Desert View Watchtower on Grand Canyon's South Rim. Angels Gate, an iconic formation in the canyon, stands in silhouette toward the upper right corner. One of the reasons I like scenes such as this is they remind me of childhood school projects...cutting random shapes from different colored sheets of paper and layering them into some interesting pattern. (Bill Ferris)

This single exposure was shot at sunset from a vantage point below Desert View Watchtower on Grand Canyon’s South Rim. Angels Gate, an iconic formation in the canyon, stands in silhouette toward the upper right corner. (Bill Ferris)

If you’re up for having some fun with your new camera, rotate the program dial to the M setting. M, stands for Manual. In this setting, you get to choose the ISO, the aperture and the length of the exposure. I realize the thought of taking responsibility for these critical settings can be intimidating. But don’t let that stop you. Sometimes, it’s fun to be a little afraid or intimidated. And you know what, it’s actually pretty easy to take good photos in manual.

We’ll start by keeping the camera in Auto, framing a shot and taking an exposure. Next, review the image and note the three critical settings: ISO, aperture and length of exposure. Write down the numbers. As we’ve discussed, ISO is the sensitivity of the camera sensor to light. ISO settings typically range from a low end of 200 to a high end of 3200 or more. Pro camera bodies often have the ability to select an ISO as low as 100 and go to 25,000 or higher. Generally speaking, the lower the ISO, the more pleasing the final image will be. As ISO sensitivity increases, noise becomes more evident in the image. At very high ISO settings, the amount of noise or grain visible in the image is substantial.

Aperture is the diameter of the lens opening allowing light into the camera body and onto the sensor. In aperture mode, rather than selecting the size of this opening, you actually select the ratio of the focal length of the lens to the aperture. This is referred to as the focal ratio or f/ratio. If you are shooting with a 50 mm lens or with a zoom lens set to 50 mm, and if the aperture is set to f/9, you know the lens focal length is nine-times the diameter of the lens opening or aperture. If you do the math, the aperture should be about 5.6 mm. Suppose you select an aperture setting of f/4.5, the lens focal length would be four-and-a-half times the aperture. That works out to roughly 11 mm. So, as the focal ratio gets smaller, the aperture or lens opening gets larger.

Finally, the length of the exposure is the amount of time the shutter is left open allowing light to hit the exposed sensor. This is also referred to as shutter speed. If your goal is to freeze a moment in time, you’ll want a short exposure or fast shutter speed. With a fast shutter speed, moving people or objects will appear stationary–frozen in time–but as the shutter speed slows, moving objects and people look more blurry. Keep in mind that there are situations where you will want to use a long exposure to capture blurred movement. Flowing water is one such situation. We’ll talk more about that a little later.

Now that you’ve taken an exposure in Auto and noted the settings, turn the mode dial to manual (M). Use the camera controls to set ISO, aperture (f/stop) and shutter speed to the settings you noted. Frame the same shot you just took and take another exposure. Then, compare this with the first frame. They should look very similar, if not identical. If you’re shooting outside in natural sunlight, any differences between the two images will most likely be attributed to a change in lighting conditions.

Let’s talk about the adjustments you might make to improve the overall look of the shot. If the shot you’ve been taking is a general wide shot of the room you’re in, you probably want to capture a good depth of field. In other words, you’ll want the lamp in the foreground and the chair next to that far wall both to be in focus. For good depth of field, you’ll want to select an f/stop in the f/8 to f/10 or f/11 range. The relatively small aperture will ensure objects both near and far will be in focus.

Suppose you really like that lamp in the foreground and you’d like to isolate it in a portrait. One way to isolate a subject in a portrait is to use a fast f/stop to create a shallow depth of field. Rather than shooting at f/9, you’re going to rotate the command dial to select an f/stop as small (fast) as your lens is capable of producing. Hopefully, you can dial in at least an f/4.5 or f/4 setting. If you can go as fast as f/2.8 or smaller, do it.

So, in which direction did you rotate the command dial and how many clicks did it take to settle on your desired f/stop? If you increased the f/stop (closed the aperture) then you’ll need to compensate by adjusting either the ISO or shutter speed. Increasing ISO will compensate for a large (slow)  f/stop by making the sensor more sensitive. A slower shutter speed will lengthen the exposure, allowing more light to pass through the restricted aperture to hit the sensor. if you adjust one or both of these settings in the proper direction by the same total number of clicks, you should be very close to compensating for the aperture change and creating a photograph that matches your expectations.

Which adjustment should you make? If you’re holding the camera by hand, you’ll want to use a shutter speed short enough to prevent any unsteadiness from creeping into the exposure. You can apply the reciprocal rule, in this scenario. The shutter speed should be no shorter than the reciprocal of the lens focal length. If you’re using a 100 mm focal length, you’ll want to shoot with a 1/100-second or faster shutter speed. The shorter the lens focal length, the longer your exposure can be when shooting handheld and still produce a sharp image.

The balance of the compensation can be made through changes to the ISO setting. Be aware that a significant increase in ISO to a setting of 1600 or higher stands a good chance of introducing unwanted noise or pixelation into the image. Of course, this is a situation where a tripod can be a godsend. If you’re able to mount the camera on a stable tripod, you can use shutter speed, alone, to compensate for a larger f/stop (smaller aperture) and still get very sharp images.

A silky water flow over Taliesin Dam at the Frank Lloyd Wright home in Taliesin, Wisconsin. (Bill Ferris)

A silky water flow over Taliesin Dam at the Frank Lloyd Wright home in Taliesin, Wisconsin. (Bill Ferris)

As mentioned, there are times when you’ll want to give priority to the shutter speed over the aperture. For example, a slow shutter speed (long exposure time) can enhance a photograph of a waterfall by giving the water a silky smooth texture. In this scenario, you’ll want an exposure of several seconds or longer. You can compensate for this by selecting a slow f/stop (aperture setting) of f/9 or f/11. Also, choose the lowest ISO setting available on your camera. And you’ll definitely need a tripod to produce a steady, sharp image with such a long exposure. If the resulting image still looks overexposed, try adding a polarizing filter to the front of the lens to further cut down the amount of light entering the camera. If the image is still overexposed, come back during that golden hour just before sunset to capture the scene at a time when the light level is reduced.

These are just a couple of ways you can begin to experiment with shooting in manual to give yourself more complete control over the photographs you make. It may not be something that immediately produces great results for you. But with time, patience and experimentation, you’ll gain a better understanding of how changes to the primary camera settings affect the final image. Ultimately, this is a path to having more creative freedom with your camera, taking better pictures and having more fun.

So, get out and shoot!

Bill Ferris | August 2013

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