Depth of FIELD (or Focus)!!!!

Most simply stated depth of field is term used to describe how much or how little of your picture is in focus. There are several factors that determine the depth of field, but none is more profound then the aperture used to capture the image. A large aperture will result in LESS depth of field then a small one will. There are other factors as well, focal length, and the distance from the camera to the subject, but neither of these are as dramatic as aperture. Aperture along with ISO directly impact the shutter speed as well, so you can't change one without changing at least one of the other 2, but for this demonstration, I will only talk about the aperture.

So what is the difference between getting an image like this:


And this:



Those of you that keep your SLR camera on the GREEN SQUARE, or the "P" mode are really losing out. If you use the camera "program mode" you are allowing the camera to decide what results you are going to get, you are giving control to the camera rather then keeping control for yourself. Aperture is the single most dramatic control we have over the finished result of our images, once you learn to control the aperture, you can decide what the finished image will look like. In some cases you may want to have as much of the picture in focus as possible, in other cases you will want to isolate the subject from the background by using the largest aperture you can.

Okay... enough typing! Here is a progression of images from the largest aperture to the smallest, meaning the least in focus to the most in focus.

















The scale from 2.8 to 32 are the "standard" f stops available on most cameras. Each stop allows in TWICE as much light as the next one, so from 2.8 to 4 is half the size. This is where the relationship between aperture and shutter speed is most evident, but that is topic for yet another thread!

As always, I hope you find the information presented here useful, and if you have any questions, please post them here!


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