In my last post, I began to discuss lighting as it pertained to exposure, and how to control the amount of light entering the camera’s lens. If you have a SLR camera with an interchangeable lens, take the lens off and look at it. Take the lens cap off, and look at the lens through the large end. As you are looking through the lens, rotate the ring on the lens that adjusts the lens opening (this should be the one behind the focusing ring). Notice how the opening of the lens changes, and that as you go from a bigger f-stop number to a smaller f-stop number, the lens opens. And as you go the other way, it closes.
This is what I was referring to in part one of this discussion. Now, imagine that you pick an f-stop setting and use only that setting for all the pictures you take in one day or on one roll of film. How can you now get proper exposure on all your shots? You vary the shutter speed. You can actually do this with a roll of film and some index cards.
Set your camera on f/8 and 1/60th of a second. Write that on the index card, and include the card in the picture. Do the same thing with different camera settings, without adjusting any lighting conditions (don’t use any flash). When you get your pictures back, or view them on your digital camera, you will see the difference between the various settings, and how it affects the exposure. Once you shoot enough pictures and see the relationship between lens opening and shutter speed, it will be much easier to get a good shot of any subject under any lighting condition.
A general rule for lighting, which works pretty well, is the “sunny 16” rule. I said before that I’m not much into rules, but this one works. For a sunny day, if you set your camera at f/16, the correct shutter speed will be whatever one is closest to the speed of your film. For example, if you are using 100 speed film, your shutter speed should be set at 1/125th of a second. Try it out, and see what you think. It works especially well if your light meter is broken, and you have no way of knowing what the correct settings should be.
We’ll get into film and lens speeds next…