This is part three of a series of articles I’m writing about digital photography, as I learn more about it. You can find links to the other articles at the bottom of this one.
After I answered some questions for myself about Film Speed, I started wondering: “What’s this f-stop Aperture thing that people keep telling me about?”
So, I sat down last night, and read a bunch of websites, and then took a bunch of photos (all inside) with different lenses to see if I could figure out what Aperture was.
The best way I can explain it is this:
Aperture is the diaphram that sits inside the lens on your camera. The aperture setting is the size of the opening between the outside world and your film or digital sensor that controls how much light passes through the lens to your sensor. It controls light and impacts depth of field.
Aperture is also related to shutter speed, which can also be used to control the amount of light that reaches your sensor, but impacts the amount of blur in your photos, not depth of field.
Together, aperture and shutter speed affect exposure, and the goal is to get the right exposure at the aperture and shutter speed you want to get.
Aperture + Shutter Speed = Exposure.
This is a key point to understand when thinking about photography. All cameras have a shutter, and all lenses have an aperture. They are manipulated to get the proper exposure for your shot, depending on what kind of settings you use.
Let’s talk about those settings.
Lenses can have a fixed aperture, or a variable aperture. I haven’t made any judgements or assumptions about which type is better: fixed or variable, though I’ve heard for professional photos, having a lens that allows you to fix the aperture while shooting is preferrable, so you can control more aspects of the process.
Apertures are usually denoted in f-numbers. f/22, f/16, f/11, f/8.0, f/5.6, f/4.0, f/2.8, f/2.0, etc…
It’s confusing for a beginner, but, if you can remember this, you’re set:
The bigger the f-number, the smaller the aperture.
The smaller the f-number, the bigger the aperture.
image borrowed from Wikipedia
So, a f/2.0 aperture is actually bigger in physical size than an f/2.8 or f/4.0 aperture.
Say it with me: The smaller the number, the bigger the aperture.
So, combined with the shutter speed, the aperture setting of your lens creates the amount of light exposed on the film or sense in your camera. But…
Aperture also adds that important photographic element called “Depth of Field” which is basically how you get a fuzzy background or a sharp background in your photo… you focus the image on an object, then to get the right depth of field, you set the aperture bigger (smaller number) to get fuzzier backgrounds. If you’d like to have sharper images, you need a smaller aperture (bigger number) so that your lens focuses across a larger space. Depth of Field is also very much affected by the focal length of your lens.
I’ll follow this article up with one on shutter speed, exposure and depth of field, and lenses, so stay tune. I’ll also link all of these articles together with added images to complete the whole process as I write them.
Other sites worth reading if you want to learn more about Aperture are:
- Aperture in Photography
- What is Aperture?
- Aperture and Depth of Field
- (If you can suggest more links, I’m happy to add them, just leave a comment on this article)
Other articles in this series:
And you can browse the rest of the Photography + Video category on this site for more links to relevant content.