Depth of field in a nutshell.....
So, have you ever wondered how to get blurred backgrounds when taking photos of a person. Have you ever wondered how professional landscape photographers get their shots so sharp? Well, You are about to learn how to control what is in focus and what is not when you are taking a photo. You will also learn when it is appropriate to used small aperture versus large aperture.
To start out you need to know what an aperture is. Basically, an aperture is a hole in your lens that controls how much light hits your camera's sensor. An aperture works like the pupil of your eye. To test this theory, go into your bathroom( I know, I could tell a joke here, but I won't) and look in the mirror. Look at the size of your pupil. Now turn off the light and wait a few seconds. Quickly turn on the light and your pupil will be larger. As your eye's adjust, your pupil will become smaller. The aperture in your camera works the same way. When you are in a low light situation, the aperture needs to be larger to let in the correct amount of light( your shutter speed also controls this, but that is a different lesson). When you are shooting
on a bright day, you aperture needs to me smaller. Got it? If not leave a comment so I can clarify more.
Anyhow, apertures are given numbers to help with standardization. F/2 is a large aperture(lets in lots of light) and F/22 is a small aperture(lets in a small amount of light).
Here is a basic scale of apertures:
f/1.4,f/2, f/2.8,f/4, f/5.6, f/8, f/11, f/16, f/22, f/32
Most lenses these days start around f/4 and go to f/22, but high quality lenses can go further. They are usually more expensive(not alway, but most of the time).
So what is so cool about a lens that goes to f/2?
Well, f/2 will give you shallow depth of field.
On the other end of the scale, f/22 will make almost everything in focus.
Let me show you what I mean.
This shot was taken at f/2.
It has shallow depth of field
This shot was taken at f/8.
See, more of it is in focus.
This shot(above) was taken at f/16(on the lens I used this was the smallest aperture).
Now, almost everything is in focus.
So, how do you use this in everyday photography you ask?
If you are taking a photo of you kid outside at the park and there is a lot of distracting stuff in the background(like weird looking parents and some goofy guy) you will want to use a f/4 or f/5.6. This will create shallow depth of field so the background will be out of focus.
If you are shooting a close up portrait, you will probably want to use f/8 so that your subject is in focus and the background is still blurred. For a long time most portrait photographers always shot at f/8, but in the last few years this has changed. You can decide for yourself how you feel about this.
If you are shooting a landscape, you probably want to use f/22 so everything is in focus and sharp!
Notice that I said probably in all the senerios above? There are always exceptions. As you become more advanced you will get better at choosing the f/stop that is appropriate.
Just a note: when you are using a small aperture(f/11-f/22) you might need to use a tripod because at small apertures you have to use a longer shutter speed. We will talk about this soon.
P.S. Comments are appreciated!!!
Thanks,
Brian
