Shooting sharp images

As a photographer, an understanding of exposure brings you many advantages. First and foremost, it helps you guarantee that your images will be sharp. Very often in classes, I'll see students come back with images that are soft, or outright blurry. "My camera is not focusing right," will be their immediate conclusion. But more often then that, the problem is not on a focus, but of shutter speed. You know that with a higher shutter speed, the shutter stays open longer, so a shutter speed at 1/30th of the second means the shutter stays opens twice as long as it does when set at 1/60th of second.

Now, if there is something in the frame that's moving while the shutter is open, then there is a good chance that thing will appear blurry in your final image. If your shutter speed is fast enough, then a moving object can be frozen, but if the shutter speed is too slow, then you might see some smearing and blurring. Now what you have to remember is that if a shutter is open, and the camera moves, you will get the same smearing and blurring, but it will be of your entire shot. In other words, camera shake can make your image appear out of focus, and shakiness is more of a problem when shutter speeds are slow.

Now there are times when your camera may not focus right--or more likely, that you are not using your camera's autofocus mechanism properly. So if you come home with an image that's soft, how do you tell if the problem was camera shake or a focusing problem? The woman in this image is out of focus, and in this case, the cause is the focusing problem. How do I know? Because the background behind her is in focus. This is a case where the autofocus mechanism decided that the background was the subject, and because I wasn't paying attention to which focus point it selected, I didn't notice that she was not chosen the subject.

Here she is again, and again she is out of focus, but this time our problem is camera shake, which you can tell because the entire frame is soft. So, now we get to your first applied exposure lesson, which is going to be learning to prevent camera shake by becoming somewhat obsessive about shutter speed.