Depth of Field
by A.B. Russell
eBay Staff Member

Last month, I mentioned a term that may be unfamiliar to you: depth of field. I don't want to go any longer without explaining it because it can be very important.

"Depth of field" refers to the amount of your image that is in acceptable focus. There's actually only one plane of focus, which is the plane your lens is focused on. By adjusting your aperture or f-stop, you can bring much more of your image into acceptable focus. In other words, you can control what part of your image will appear to be well focused, and which part won’t be.

In simple terms, the smaller the aperture, the more depth of field you will achieve. If you make a photo with your lens aperture wide open, set at, say, f 2.8, only the plane you're focused at will be sharp. If you close down the aperture to, for instance, f 11, much more of the entire photo will be in focus. This can work either for or against you, depending on the image you want to make.

If you are photographing an item that is flat (or nearly flat) and you have a distracting background, you can minimize the effect of the background by using only a small area of depth. If your item needs more depth and your background is less distracting, you may need to close your lens down to get the entire object in focus.

If you have an object that requires depth but you have a distracting background, the problem is obviously more difficult, but not necessarily impossible. If you can move the object farther away from the background and back the camera up as well, you may be able to use depth of focus somewhat better. If, however, you’re photographing something as large as a car and the background is distracting, you may need to find a different place to take the shot.

Most cameras that allow you to change the aperture will have a method of previewing the depth of field. They do this by closing the aperture to what it will be when the photograph is made. Unfortunately, this is often too dark to see much of the image. Unless you're making an image where the depth is critical, the effort to use this feature may not be worth the time and trouble.

Manual focus cameras usually have a scale on the barrel of the lens that will show you approximately how much of your image will be in focus. Fortunately, it's not nearly as hard to use as it is to explain! Because there are few people using manual cameras these days, I'm going to suggest that you refer to your camera manual, or see if you can get help using it from a book or camera store.

There are a couple other factors that will affect your depth of field. A wide angle lens will usually offer more depth than one with a narrow angle of view. The distance from the camera to the subject will also show a difference. But remember that you want to keep the item you're selling up front in the image. Usually the most important thing you can do to achieve depth in your image is to use a small aperture.