Your Choice of Aperture Affects More Than Depth of Field

When I took these pictures at f11 and f4, I just wanted to change the depth of field. But in photography, every change in settings sets off a chain reaction that can produce unexpected – and sometimes unwanted – collateral effects.

At f4, I get narrow depth of field. I also get a low-noise image at ISO200.

At f11, I get greater depth of field, but a couple other things change too. For one, I use Auto-ISO, so to maintain my preferred shutter speed of 1/200, the camera pushed the ISO to 1600 - hence the grainier image. Also, the flash had to put out more power, which caused additional reflection from the yellow walls, throwing a color cast over the image. I also got more reflective bounce from the counter top, lightening the shadows on Panda's chin.

When we make a decision to change camera settings, we need to think through the entire image chain to make sure we consider the consequences. For example, very large and very small aperture settings can reduce sharpness. Maintaining shutter speed while changing aperture will require changes in ISO sensitivity. It’s all connected!

5 Comments

Filed under Camera Settings

5 responses to “Your Choice of Aperture Affects More Than Depth of Field

  1. A good point indeed. I was once talked into using auto ISO and I disliked it for this very reason, I ended up with all sorts of peculiar problems. If I need to maintain a certain shutter speed I would prefer to use Shutter priority or manual

    • For a lot of what I do, auto-ISO is perfect, because I’m trying to catch performers as they move in and out of stage lights. So I manually lock in a shutter speed and aperture, spot meter off the performer’s face, and let the auto-ISO handle the exposure. In those cases, grainy images are an acceptable trade-off. In the studio or other controlled conditions, it’s all manual all the time!

  2. myrna

    well … i like cat number one of course … always good to try a few things if your cat subject is willing to sit still for awhile! a little distraction in background and perhaps a move one way or another would have taken care of that

  3. Hey Dean,

    Interesting to see your shots. I like the lantana shot even though I have real issues with lantana. Does the blog catch much traffic?

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