Have you ever wondered why some photographs grabbed your attention more so than others? If so, chances are, the photographer was using Depth of Field techniques to draw attention to the subject in a dramatic way. What is "Depth of Field?" In a nutshell, it's the area you see in a photograph that is in sharp focus. Now, the sharp focus can be a small portion of the photograph or the entire photograph can be in sharp focus. Thats where you get two different Depths of Field.

In the above photographs, I used a Shallow (smaller) Depth of Field. What this does, is draw your attention to the subject--the peacock or the people in the photos above--by blurring out the foreground and background. The photo of the peacock blurs out the foreground as well as the background. The photos of the people blur out the background portion of the images. This blurring effect draws your attention to the subject by getting rid of anything distracting in the background. If you have a lot of greenery in the background the colors blur and take on a studio backdrop feel sometimes.

In the photos below, you will see a Greater Depth of field. This is where everything in the photograph is in focus from the foreground all the way to infinity. More of the photograph is in sharp focus which makes sure you see everything clearly, especially if you are photographing a scenic landscape. Look at each photo below. You will see that the photographs are sharp all over. This technique allows you to highlight a great expanse of area sharply.

So how do you create shallow or great Depth of field? It has to do with the aperture or F/Stop setting on the lens of the camera. The aperture is the opening in the lens. A larger opening creates Shallow Depth of Field. Likewise, a smaller opening creates a Greater Depth of Field. If you have a lens that has the aperture ring on it, you can adjust your F/Stop manually on the lens. If you have a more up to date digital camera or film camera, you can set your camera to Aperture priority mode. In this mode, all you have to do is set the aperture to the appropriate setting in order to get the desired Depth of Field.The camera will automatically set the appropriate shutter speed to ensure proper exposure.

The aperture priority mode is labeled as "AV" on the camera program dial.

The one thing to pay attention to in aperture priority mode is to keep an eye on the shutter speed. If it drops below 1/60th of a second, you could experience camera shake and thereby cause blurring in your photograph. If you are using a telephoto lens I would make sure to keep the shutter around 1/250 sec.  

So, what F/Stop (aperture) setting gives which effect? On the lens or inside the viewfinder screen, you will see numbers like these: F/1.4 - F/2.8 - F/4.0 - F/5.6 - F/8.0 - F/11 - F/16 - F/22 . There will also be numbers in between these numbers. They are 1/2 steps or 1/3 steps. The way I originally learned which ones did what, was a bit tricky. Basically, I was told the larger the number, the smaller the opening and the smaller the number, the larger the opening. Well, that is just to easy to get mixed up, which I often did. Then, It finally dawned on me. When I'm looking through the lens, I'm not seeing the lens opening up and getting bigger or smaller. I did however, notice the F/Stop numbers in the viewfinder.

That is when I discovered a better way to remember which F/Stops gave me shallow D.O.F or Greater D.O.F. What I do is this. If I want a SMALLER (Shallow) D.O.F., I need to use a SMALLER F/Stop number e.g. F/1.4 or
F/ 4.0. If I want a Greater D.O.F. then I need to use a GREATER F/Stop number e.g. F/16 or F/22. This made remembering which one was which much easier. I think you will also find it much simpler to remember. I also came up with a visual that will help cement this into your memory bank. See Below for my "Football Field" analogy as well as a side by side comparison of  Smaller (shallow) vs. Greater D.O.F..