I mean you did make that background all nice and blurry today. Aperture, you rock. I talk to things a lot guys, it happens.
Let's just get on with it already...
1. What is aperture?
Aperture is basically the hole inside the camera that allows light into the lens. The larger the hole, the more light can enter. The smaller the hole, the less light. I really like Bryan Peterson's analogy of light compared to water coming out of a faucet. Think of aperture as the opening of a faucet. The more you open the faucet, the greater amount of water goes into the sink. If you turn the water on high, it often hits something and splatters out. Water be everywhere! Now if you turn the water on low, it is a more controlled amount and doesn't splatter as much. Even better, it might not splatter at all and you have dry pants.
Now... think of light as water.
When you have a big hole, tons of light pours in. The light hits your subject, then scatters everywhere else. When this happens, the subject is in focus and everything else is blurred. That's what makes background blur and dreamy bokeh. Bokeh is what we call all that blur of light behind a subject.
Now, when you have a small hole... a smaller amount of light is coming in. This light is more controlled, less messy. The light hits your subject but doesn't scatter. When this happens, everything is in focus. That's how we get images with a great depth of field. This water / sink analogy can also be used with a paint bucket. Have you poured a crap ton of paint out at once? Did it splatter? What happened when you used more control (or those little lids with the hole?) Less splatter. And probably less blue paint in your hair.
2. Aperture controls depth of field
Pictures with shallow depth of field (aka subject in focus, background out of focus) require a big aperture such as f/2.8. Pictures with everything in focus (from front to back) require a small aperture such as f/22. Now lots of people get confused with this, because f/22 looks bigger than f/2.8 - seriously I get that. It drove me banana pants crazy. It helped me to think of it as a fraction (this is kinda not technical but sorta true, but not really) so if you imagine that 1/2.8 is much bigger than 1/22, I don't know it works for me. My mom likes to see it as a pizza. I still don't get the pizza thing. But hey, you gotta do what works for you.
3. What you need to know:
- aperture is called an "f-stop"
- it is designated by f/ (such as f/2.0)
- it controls the depth of field (shallow focus or greater focus) in a picture
- "open up the lens" means make the hole bigger
- "stopping down the lens" means to make the hole smaller
- "shooting in wide open" means shooting with the biggest aperture your lens has
- shooting wide open is helpful in low-light situations
- big apertures = the smaller numbers (blur background) like f/1.2, f/2.0, f/2.8
- small apertures = the bigger numbers (lots of focus) like f/18, f/22/f32
- for small groups of people stay at f/4 or smaller (for more depth of field)
Now let's get into some photo examples of aperture!
f/1.2 is a very shallow depth of field - its a very big hole. You can easily take a picture of someone and only get their nose and an eyeball in focus. It's tricky getting things in focus at such a wide open aperture but you get better at it with practice.
f/3.5 - is the usual suspect. You know that kit lens that came with your camera? Probably opens up to f/3.5. This is a great aperture for shooting a small group of 2-3 people, but it is limited on the amount of creamy blur you'll get. f/3.5 isn't very good for low light situations... when you really need to let in more light.
f/14 is a small aperture. It's going to get lots of stuff in focus, from front to back. Use this type of aperture on vacation when you love the surroundings, at that big family reunion (giant group of people) and anytime you want most everything in good focus. Usually the only time I use this small of aperture is when I'm on vacation - I do love breathtaking vistas... I want to remember it all.
Ready to try your hand at shooting in manual? Focus on aperture for a week. Choose a subject (or two) and try changing the aperture to see how it changes the look of the subject. You'll need to pick the aperture first, then adjust the other settings accordingly. Don't forget... anytime you change the aperture the other settings (shutter speed and ISO) will have to be adjusted as well (given you achieved a correct exposure in the first place.) If you change the aperture but forget to adjust the others, then your photo will be too dark or too bright.
Have fun and happy shooting.