Ok folks, here we go! Are you ready? Are you sure?
Today we’re going to talk about f-stops and aperture. F-stops are the fixed stops or numbers for setting lens apertures. The aperture is the size of the open iris of the lens. They go together.
See, that’s not too difficult, is it?
Next, let me tell you the part that gets people confused: The number of the f-stop gets higher as the aperture gets smaller. And, the f-stop number gets lower as the aperture gets bigger.
I don’t know who made this up, but that’s just the way it is. Well, yes I think I do know who is to blame, but I’m not sure. I think it was Eastman Kodak. Anyway, here is a little graphic for those of you who learn better with pictures:
See what I mean?
Most DSLR cameras and some point and shoot models have the ability to change the aperture, making the lens opening bigger or smaller. “Ok,” you say, “but why would I want to do that?”
Here are a few reasons:
1. Making your aperture bigger (smaller f-stop number) lets in more light. This makes a big difference when you are inside and don’t want to use your flash (say, at a wedding).
2. Making your aperture bigger also allows you to make your subject stand out a bit. It tends to blur the background, causing your eye to be drawn to the subject of your photo. See the example below.
Flowers at F5
Flowers at F32
3. Making your aperture smaller (bigger number) allows more of your picture to be in focus – to a point. Get too high a number and you get what’s called diffraction. You don’t want that!
So what’s the best f-stop to use? That depends on your lighting, subject and lens. All lenses have a f-stop that is their “favorite”. You just need to find it. Usually, between 5.6 and 8.0 is your best middle of road place to be.
So, if your camera has an Aperture priority setting (you will know this, since you read the manual last week), try using it to take some test shots. Play around with the f-stops for a while and see what you think. Aperture priority will automatically set your camera speed, so you don’t need to worry about that — until next week, because that’s what we’ll be talking about!
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