I’ve had a few questions since my last post so I wanted to provide a little more information regarding this depth of field subject. And I promise, I will stay away from all the mathematical formulas (I was never any good at math) and try to make this as simple and understandable as possible. However, if you really are interested in calculating it yourself but don’t want to define mathematical variables and balance equations, you can use this Online Depth of Field Calculator. Now, to my simple explanation.
Depth of field refers to the background and foreground areas around the subject (in my case, the person that I’m photographing) that appear to be in focus. There are really three variables that go in to determining depth of focus, one of which I’ve already touched on this week. They are Aperture (or f-stop number), focal length (in my aperture example, the focal length of the lens I used was 50mm), and distance from the subject (in example, when I took the photos to demonstrate aperture, I was standing about 5 feet away from the subject). Those three ingredients are what help determine depth of field. Consequently, changing any one of those variables will change the output and the final photograph that results.
I think I’ll quit while I’m ahead and end my 3rd-grade level lesson right there. Plus, I need to get about 30 plastic eggs ready for an Easter egg hunt that we’re doing this afternoon with friends from my MOPS group. However, if you have any more questions, please contact me or leave a comment and I’ll do my best to answer. Also, just to add on to the aperture discussion from a couple of days ago, I should point out that if you are shooting manually (like I do) as opposed to using the “Auto” setting on your camera, you’ll need to remember to adjust your shutter speed accordingly to accommodate a wide open aperture. Otherwise, you’ll overexpose your photos. Because remember, if you have your aperture wide open (a smaller number), more light is allowed in. The longer your shutter is open, the more light and you’ll get overexposed and washed-out photos. So, remember to adjust your shutter speed or if your camera has a mode for “aperture priority”, you can set the aperture you want and the camera should adjust (shutter speed and ISO) accordingly. And yes, we’ll cover ISO on another day. Until then….