Digital Photography 101: Sharpen your focus
Tips for making your photographs as sharp as possible
by Katherine Gray on March 26, 2011
Filed under: Cameras/Camcorders
Sometimes it’s good to have parts of your image out of focus, as when you’re intentionally creating bokeh, but generally speaking, blur is bad. Unintentional blur can be caused by the motion of your subject, the motion of the camera as you’re holding it, or incorrect focus. There are several things you can do to combat unintentional blur and keep your photographs tack-sharp and beautiful!
Use a tripod
Sometimes it’s just not practical to carry a tripod around with you, but this important piece of equipment is your best defense against blur caused by camera shake. I recall being told as a photography student that no human being can hold a camera steady at shutter speeds slower than 1/60th of a second. I’ve found personally that if you havevery steady hands, you might be able to get away with speeds as slow as 1/30th of a second.
Even if you’re able to hold as still as a statue, it’s still a good idea to use a tripod if you can, especially if you’re using a large, heavy lens. Tripods let you use very slow shutter speeds, which are essential for low-light situations.
Get a hold of yourself
If you can’t use a tripod, be sure to practice good photography form. Hold the camera in both hands, keep your elbows in close to your sides, and if possible, brace yourself against a wall or other immobile object. Keep your feet planted wide and your stance as solid as possible. If you’re using a camera with an LCD screen, you might be tempted to hold it away from your body, but try to resist that temptation. Your arms probably aren’t as steady as you think they are!
Shutter speed, aperture, and ISO
Understanding shutter speed, aperture, and ISO are key to getting sharp photographs.
As we mentioned earlier, shutter speed has a large impact on whether your pictures will be in focus or horribly blurred. Sometimes a slow shutter speed is very useful for creating intentional blur, as when shooting pictures of water, but generally you should be sure to use a shutter speed that’s fast enough to capture the action you’re photographing. To freeze the action in a horse race, for example, you’ll need to use a much faster shutter speed than if your subject is a solid, immobile building. Also remember that the longer and heavier your lens, the faster the shutter speed you’ll need to use to compensate.
Aperture, on the other hand, has a direct effect on the depth of field, or the area of your image that is in focus. A smaller aperture (which means a higher number, such as f/20) means a larger depth of field, and a larger aperture (a smaller number such as f/4) will give you a smaller depth of field. The latter case means you have to be much more careful to make sure that the area you want to be in focus is, in fact, in focus. For example, if you want your child’s adorable face to be in focus but the background behind her to be softly blurred, you’ll want to use a larger aperture and be sure you set your focus carefully.
ISO controls the sensitivity of your camera’s sensor and is all about trade-offs. Using a higher ISO will allow you to use a faster shutter speed in low-light conditions but will result in more “noise,” which is the graininess you see when you zoom in. For the sharpest pictures, you should try to keep the ISO settings as low as possible, but if you’re shooting somewhere like a concert or an indoor birthday party, using a higher ISO might give you the sensitivity you need to take good pictures without a flash.
Turn off auto-focus
Usually your camera’s auto-focus function works perfectly well. There are some situations, though, when either you want more control than it can reasonably provide, or the situation just makes it difficult for the camera to decide what to focus on.
Macro photography is one area in which you’ll definitely want to be able to choose exactly what part of the frame is in focus. Another is when you’re shooting through glass or some obstruction like a wire fence or window screen. In that situation, your camera will likely try to focus on the obstruction rather than the subject behind it, and you’ll probably have much better luck if you focus manually. This is very common at zoos, where of course it’s not practical (or legal!) to take your pictures from the other side of the fence. I once lost half a day’s worth of photographs at a big cat rescue park before it finally occurred to me that even though the camera wanted to focus on the fence between me and those big kitties, I didn’t have to let it do so!
Learning how to properly control focus is one of the most important tactics in a photographer’s arsenal. Once you’ve mastered these techniques, you’ll see a marked improvement in your pictures!
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