Testing and Training

I have a new lens which is the equivalent of a 90mm 1.8 lens on my camera. Of course when you have a new lens you have to test it out to see what it can do. This was shot at f/2.0, 1/125 sec, ISO 200. As you can see the lens can do very well.

I shot a bunch of kids on this day but about 50% of them didn't turn out as well. When you are shooting with a big aperture (f/1.8 to 2.8) you have very little depth of field or very little that will be in focus and sharp. The critical focus area may not be more than a couple of inches. This was a big aperture so there is a wonderful creamy blur in the background and I love the technique because it makes the subject pop. You want the eyes or at least the eye nearest the camera to be in sharp focus. There could be the exception to this but this rule works best most of the time.

Since I shoot more scenes than people and usually use a smaller aperture that increases the depth of field, I have a tendency to push the shutter button down a bit to get a focus hold and then check the image for framing before pushing the button down all the way. When you want to use the big aperture with any subject that could move, even an inch or two, the focus hold doesn't work because the object you want critically sharp will go out of the critically sharp focus area.

The lens is fine. The camera is smart and can be directed to focus on the face, the face and eyes, the face and right eye, or the face and left eye. It seems it is the photographer that needs training and testing.