What is Aperture??
There is a mechanism inside your lens that can be controlled to let in a certain amount of light, this is called the Aperture. Not only does this control the amount of light, but it also controls the Depth of Field, or DoF, for short.
So how does it work?
Aperture is measured by numbers called f-stops. These numbers are a little weird because it’s backward. Here’s what I mean by that:
The LOWER the number, the MORE light that’s coming in.
The HIGHER the number, the LESS light that’s coming in.
Take a look at the illustration to help you visualize what actually happens to the aperture when you change the number. See, the smaller number means a bigger opening and vice versa, I told you it was weird.
Tell me more!
In this case, f/1.8 would be wide open (that depends on your lens) which would allow in the maximum amount of light for that lens. This will also give you a smaller depth of field, which blurs the background of your photo and only keeps in focus whatever you tell it to focus on. More on that here -> (Depth of Field).
At f/16, the lens is closed down, which means it is only allowing in the minimum amount of light. As opposed to the DoF on the f/1.8, this will give you a larger depth of field, which will basically keep everything in focus, background, and foreground.
Don’t worry too much about the numbers, just remember what changing the numbers does; higher number = less light, lower number = more light
That’s all folks!
That’s pretty much all you need to know about aperture for right now. The other 2 key elements of an Exposure Triangle are Shutter Speed, and ISO. Once you learn how to use all 3 then you will become a master of the exposure triangle which = better pictures!