Well… now we have come to… in my opinion… the most important “math-based you gotta know this to create great photos” subject.
Aperture control. The numbers are simple…. most cameras…. make that good cameras…. will accept different lenses. Basically…. the better the lens…. the more flexibility it will give you. And yes… just like in golf… flexibility is key to getting that great shot. Lenses are defined on two scales…. millimeter “length” ( zoom or prime) and their ability to “open up” or “stop down”… in order to allow more or less light in. And this number is expressed in “f-stops.” The better lenses usually have a range of f-2.8 to f-22. Usually. Ansel Adams was a key member in the “64 club”…. yep… his lenses could go to f-64…. allowing the photo to be so sharp you could see an ant a mile away. Well… close.
Quickly and simply… and to use an analogy to explain what is happening when you “open up or stop down”. Think of the f-2.8 setting… as a big paint roller brush… you get the job done quickly but there is a “downside or plus side” depending upon what you wanted to shot to look like. You will achieve a nice exposure quickly… but it will be sharp only in a thin area of the photo. It will have a thin “depth of field.” Now…. on the other hand if you had chosen f-22… the exposure would take longer but the result is a photo that is sharp from your foot to the horizon… or darn close.
Take a peek at the three shots above…. all were shot with an f-stop close to f-2.8. All three have a very shallow depth of field…. and the beauty of this is that the subject is sharp and everything before and after it… is soft…therefore giving more emphasis to the subject. As I said… I love this stuff… it draws you in and has a simple look because the eye will travel to what is sharp and not waste any energy looking at the soft part of the image. It is a very sophisticated use of the “leading lines” strategy. Luscious stuff if I do say myself.
Now… look below… a lovely Provence landscape… and since I used a f-stop near f-22…. it is extremely sharp. Keeping with the painting analogy…. think of f-22 and that end of the f-stop spectrum as a very very small but precise painting brush… perfect for painting extreme detail. In fact the original photo was so sharp I could easily see a tiny tiny tiny black speck in the sky. When I enlarged the photo to remove the speck… it turned out to be a flying crow!
Experiment…. just remember… you are the photographer not the camera. It is only a tool. A great one but… only a tool.