Photography~girl~ wrote:yes, it does....a little.
and I have noticed things like f/2.8 a lot...what does that stand for?
f/2.8 stands for the widest aperture of that lens. The aperture is how wide the lens will open, the wider it opens, the more light it allows in. Aperture is also often referred to in "stops". Stops are measured with 2 numbers: 1.0 and 1.4 then they are doubled and those numbers are dovetailed to calculate the next stop.
Examples of the doubling:
1.0 x 2 = 2 x2 = 4 x 2 = 8 x2 = 16 x 2 = 32 x 2 =64.
1.4 x2 = 2.8 x2 = 5.6 x 2 = 11 x2 = 22 x 2 = 44.
Then these groups of numbers are dovetailed (one from one group, the next from the other group, etc.) So your stops look like this:
1.0, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, 44, 64 - 64 is normally the lowest stop and this only allows a small amount of light to reach the sensor/film. As you go backwards reducing the numbers (64 to 44 to 32) each stop allows double the amount of light of the previous setting.
You're probably wondering why these numbers are important. They allow you to determine what type of pic you will produce by selecting a particular aperture. The wider the opening, the shallower the depth of field (this is what gives you the out of focus background). A wide opening also allows you to use a faster shutter speed and/or a lower ISO setting. The lower ISO settings help to eliminate noise and the higher shutter speed allows you to stop the action of faster moving subjects. The wider the aperture also means the more expensive the lens (under most conditions) since more glass is required to make it.
Does any of this make sense to you? Here are a few examples.
If you wanted to blur water running in a stream, you need a narrow aperture since that would increase the time the shutter would have to be open to capture the image. Also, when shooting landscape shots you want a very large depth of field, so you want a narrow aperture. However, if you were shooting race cars and wanted to stop the action, you would want a very fast shutter speed so you would need to open the aperture to get as much light as quickly as possible.
The main thing to consider is that aperture, shutter speed and ISO settings all work together to determine what type of image you will capture. There are a lot of good books that explain this much better than I have and to produce the type of pics you want, you'll need to have a pretty good understanding of how these numbers work together.
edited to add: I should have mentioned there is a rule called Sunny f/16 to help you remember/calculate how these settings work together. You can 'google' it to get a good explanation of it. Here's one link that explains it: http://www.photomigrations.com/articles/0403200.htm
Once you move to an SLR or DSLR, you will need to be familiar with these settings to get the most out of your camera.