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It's one of the greatest tools available to photographers, it's easy to use, and yet it's among the least known and used abilities of a camera today. Pro photographers have used it for decades, but the amateur can use these same techniques without paying the professional price. It's called depth of field, and it's accessed through the use of the aperture.
The aperture, simply put, is the hole that light comes through in your camera. Light passes through the front of the lens, through a series of glass pieces, through a hole at the back of the lens, and into the camera. The aperture is the hole in the back of the lens, and you get to control this vital part of the camera, if you decide to want to bump up your pictures. You can place the camera on auto, and the camera will adjust its aperture, shutter and more to the situation it sees. By placing the camera in more manual modes, you take on powerful and personal control, and YOU get to decide what you want to create with your photographs.
An important factor here is lighting. Any photography relies heavily on the lighting that you are using, whether it be from the natural, ambient light around you, or artificial light, like a strobe or other flash unit. Especially while using natural light, it will be important to use a tripod to keep the camera steady while shooting. If you are shooting on a cloudy day, without much light, then the camera must compensate for less light by having a longer shutter speed, which it will do automatically in the mode I'll be explaining in a moment. A longer shutter speed means the camera won't be able to have a clearly focused picture without the use of the tripod.
Depth of field simply means the area of focus, or the area in the picture that is in focus might be a more accurate term. Photography is a two dimensional medium, having height and width, but it lacks depth, the third dimension. Your photography can create the illusion of that depth through a few easy camera settings. You may be asking yourself, why would I want to create the illusion of depth, and what is it good for? Part of the reason is to create a sense of emphasis. When you take a picture of a large area, with trees, birds, squirrels, people, rocks, etc, what is the thing or object that you are zeroing in on? Is there anything that you really want to emphasize to your viewer? If so, it's probably getting lost in the crowd of other things on the scene. The squirrels are so small you can barely see them, the people are walking their dogs, and the trees are swaying in the breeze. But what if you wanted to focus on the viewer on the flowers in the garden? When you create emphasis on an object, it strengthens your photo, and actually guides the eye of the viewer to that object. You could take pictures to create a story about that, as you can read in my article about photo stories. When you get in to take close-ups of the flowers is where the possibilities of great photography begin.
Emphasize the garden by focusing in on one or two flowers at a time. Grab a tripod, get down to eye level with them, and then get ready. Place your camera in a mode that allows you to change your aperture; the mode is usually called "A", or "AV" on some models. Film cameras can allow these changes too, on SLR models. They require you to simply change the f-stop manually on the aperture ring. On your digital camera, use your selector buttons to change your aperture. You'll see on your digital camera, most likely, a letter f, with the number on the readout on either the monitor, or the info panel on the top of the camera, or perhaps both areas. The f means f-stop, which is the name commonly used to describe the number of the aperture setting. The best way to emphasize a flower is to have only that flower in focus, and to have the rest out of focus. Change your aperture to a really low number, such as 2.8, 4, or 5.6. When the lens is at a low number like this, the lens hole is wide open, but it is creating a small area or depth of field; basically an inch or two will be in focus. Focus your camera, and shoot. Now, look at the camera, and look at your pictures. The one or two flowers should be in focus, but do you see how the background is fuzzy and out of focus? This is what is called a "shallow depth of field", and that comes from using a small number f-stop. That's because you've taken control of your camera, and changed the outcome! Because only the flower is in focus, and the rest is blurred out, you have guided your viewer to what YOU want to emphasize! You have used one of the most powerful tools available for a photographer to bring a new focus to your pictures. Try this with a lot of different scenes; look how the item is forced to really stand out for you because it's the only thing in focus.
Now, on the opposite end of the spectrum are the pictures that have the entire photograph in focus; such as a lighthouse standing out from the beach, with horseshoe crab shells in the immediate foreground. This is also done by changing the depth of field of your camera. Here, you again change your aperture, but this time place it on a high number like 16, 22, 28, etc. This is to create a large depth of field by using a small hole in the back of the lens. Again, you must use a tripod to keep the camera steady. Take a picture with something in the near foreground, such as a rock or the crab shells, and then compose your picture with a mountain or some other object some distance away, focus, and shoot. Remember to use the rule of thirds here for additional emphasis. As you'll see, both areas should be in focus, again showing the third dimension and creating the illusion of depth. This is a large depth of field.
It's a little known tool in the photographer's toolbox, but almost any camera made in the past four years will have some sort of ability to work with depth of field, whether they have a point and shoot or DSLR. Every photographer, of every level, has the ability, through practice, to create beautiful photographs that can rival those of the pros, by using the tools available with every camera. Use the strength of depth of field when you create the third dimension in your photographs, and add a new and incredibly
powerful personal dimension to your photography.
