We looked at the Shooting Mode Dial, and now we are going to begin thinking photographs. We dispensed using the symbols, like the mountain, or star with a moon symbol….too complicated for me. I go right to the “creative zone,” the P, Tv, Av, and M for taking my photographs, and encourage you to do the same, especially after I explain how simple it can be. Actually you can start right away, because the nice thing about digital is it cost you very little to experiment.
The P, Tv, Av and M settings all deal with the interplay between the shutter (curtain) and aperture (diaphragm), and they control exposure, that is, the proper amount of light to hit the capture medium. This can still be traditional film, but today in our digital world we are talking “chip.” Remember photography means painting with light, and we need the right about to expose our subject.
You may ask why it takes both an aperture and shutter to control the light exposure. It’s a valid question, it does not require both. The first cameras used only a pin hole, which is a fixed aperture to make exposures. But having use of both the aperture and shutter has its advantages. Learning how and what advantages these two controls provide and how they interplay is not at all complicated, and the rewards for understanding process will allow immense leaps in your growth as a photographer.
From the original use of the pin hole camera, we quickly learned that the size of the aperture, in addition to controlling how much light reaches the (photo capturing) chip, also controls what photographers call “depth of field.” The smaller the aperture (diaphragm) the greater the depth of field and a larger aperture decreases it.
To really improve your photography skill, you have to know what this means, and the diagram should help you visualize my following description. You will notice from the diagram that a small aperture is, for instance, f/8. This letter-number combination is called an f stop. Opening up the lens (full f stops) from f/8 to f/5.6 to f/4 to f/2.8 makes for doubling the size of the opening by each lower numbered f stop. With each opening up there is a doubling in the amount of light that enters the camera, while at the same time each opening up from f/8 to f/2.8 makes it more difficult to keep close and distant subjects in focus. The inverse, closing down to a higher number, from f2.8 to f/8, makes for smaller lens aperture openings, with each f stop smaller allowing half the light in to expose, and at the same time increasing what near and distant subjects can remain in focus. So to open up and close down f stops, controls light and the depth of field, that is the depth of focus, or what will be blurry and what will be sharp. It’s your choice. This is why the lens aperture is a must have for all of us photographers.
With this information, the next time you take a photograph of a friend or loved one you can consider how you want the photograph of your favorite subject to look. If you would like to solely focus on your subject, you can best achieve this result by having the background (and foreground) soft, that is, out of focus. By looking at the diagram can you determine how to achieve this desired result? Or it could be you want to show your favorite subject on deck and clearly show (in focus) distant Islands in the background. How would you best handle this photographically? That’s right, in the 1st instance you would want to use a low or open f stop such as f/5.6, f/4, f/2.8, and even more open f/2. The latter scenario would require a more closed, smaller, higher f stop, like f/11, f/16, or even higher, f/22. But in doing either you would also, respectively, allow in more light or less light, and this will be one reason the shutter comes into play. But I’ve gone overboard… until next time, permission to come ashore. Send me your questions to possibly cover in next issue.