Recently, I heard a client lamenting the lack of depth of field he was getting in his spontaneous digital portraits. If he was photgoraphing two people, one would inevitably be in-focus and the other out. Having only ever worked in Program mode he new nothing of this thing we call aperture. Here's what to remember:
- Most good lenses have a variable lens aperture.
- The bigger the aperture number (eg.f 22) depth of field is increased.
- The smaller the aperture number (eg.f 2.0) depth of field is decreased.
- When depth of field is increased (higher aperture number) more will be in-focus.
- When depth of field is decreased (lower aperture number) less will be in-focus.
Reducing depth of field is great for a portrait of a single person. It helps to eliminate distracting elements in the background by blurring them.
Increasing depth of field is great for a landscape where you might want everything from the foreground to the background to be super sharp.
Lastly, my client friend, venture out of Program mode, into sayyyyy...Aperture Priority mode. in AP mode you can force the camera to use whatever aperture you need to get the job done. It accomplishes this by adjusting the shutter speed to accomodate what's really important to you, aperture. That's a priority.