Weekly photo challenge: arranged —or the effect of f-stopPosted: April 6, 2012
I’m trying to jump back into the weekly photo challenge. I enjoyed doing it for a while and then I fell out of sync. Here are a few photos from the archives of my Photography I class. Even though the arrangement of Disney character toys on my porch railing looks like something a 5-year-old child might do, it wasn’t. I did it for a class to show the effect of the f-stop, or aperture, of a camera on the photograph.
When you snap a photo the lens opens up a certain amount (aperture, lens opening, or f-stop) for a period of time (shutter speed). If you have a fancy camera, you can adjust one or both of these variables. Some of the simpler automatic point and shoot cameras will allow you to adjust these settings in a manual mode of operation.
The size of the lens opening and the amount of time it is open determine the amount of light that contacts the film, or more likely today, the digital receptor (probably has a name that I can’t recall at the moment). The amount of light determines the exposure or whether your photograph will come out too dark, light, or just right. With the automatics we have now, the photographer doesn’t usually have to worry about exposure. But if you’re like me and grew up with a film camera, you’ve probably seen your fair share of under or over exposed prints.
The second lesson we had in my Photography I class was experimenting with the f-stop to see the effect on a photo. The f-stop is actually expressed as a fraction: f/4, f/8, f/22, etc. The smaller the f-stop numeral, the wider the lens opening (1/4 of a pie is bigger than 1/8). The size of the opening determines not only how much light gets in, it also effects how much of the image will be sharply in focus, known as the depth of field. As the opening gets smaller (f/22 for example), the more of the scene from near to far gets into focus. In the above photo, all the Disney characters are in focus. Mostly. (I think the lack of crystal sharpness was due to the photographer and not the f-stop. But it was only my second week in class, so I think I deserve a break.) You might also notice that the trees and the house in the background are clearly in focus.
In this photo, with a larger aperture, f/4, only a select portion of the photograph is in focus. The above characters in line are out of focus until you get past Esmeralda. Then Captain Phoebus and Mulan are sharply in focus. Beyond them, things start blurring again. I must have focused my camera on Captain Phoebus or Mulan (I think I was probably trying to get Esmeralda and just missed). You can also see that the background trees and house are blurry.
Opening the aperture, or setting the camera to a lower f-stop number, is one method to get a better picture in a low-light situation, if you are primarily concerned with a single focus area. I use it all the time.
Sometimes I use a larger aperture, (low f-stop number like 4 or 5.6) just because I like the effect.