Your camera is really smart, you know.
Like crazy smart. In the old days, cameras relied on film and chemistry to make photographs. Now days, it’s all done with computer data collected on a sensor. The sensor understands how to turn light into bunches of 0’s and 1’s and make digital data, huge amounts of it, and construct that into a photograph. It boggles my mind.
Admittedly, I do not understand how the sensor works. But, I do know how light works and how to get just the right amount of it to hit that sensor to make a pretty picture.
Now that we know what exposure is, we’ll learn how to control it.
First, I need you to imagine with me. Picture a hot summer day, a dirty car, and a soap-filled sponge. You know what else we need, right? A bucket of water and a hose to fill it.
So, you’ve got a bucket, right?
And you’ve got a hose?
Where’s the water? From the faucet. Got it?
Hose, bucket, faucet, water.
This is the secret to a properly exposed photo.
The primary resource in our illustration is water. Water=light. We need water; we need light. That’s the deal.
How much water do you need? Enough to fill the bucket.
Ok, so your hose is attached to the faucet. You turn the faucet on and water begins to flow. When the bucket is full, you turn off the faucet. Simple enough.
Shutter speed = how long you leave the faucet on.
Shutter speed is the easiest to understand of the functions that control the light in your camera. You open the shutter, light comes in. Close the shutter, no more light. You can even see the shutter “blink” when you take a photo.
Leaving the shutter open is just like leaving the faucet on. The longer it’s on/open, the more water/light.
Shutter speed is measured in seconds, or more accurately, fractions of a second. 1/20 for example would be one-twentieth of a second–FAST. 1/500 would be one five-hundredth of a second–VERY FAST! And 1/1250 would be one one-thousand-two-hundred-fiftieth of a second (huh??) RIDICULOUSLY FAST. The top speed on my camera is 1/8000. I can’t even.
We’ll learn more about shutter speed later, but for now, know that a higher shutter speed is generally preferred. Just like you wouldn’t want to take all day to fill that bucket with water.
ISO = the bucket
Imagine you turn on the faucet to fill your bucket and it’s a 20 gallon giganto. It’s going to take longer to fill that bucket. Now, imagine you’re filling a pint-sized mini bucket. Going to be pretty quick, right?
ISO is like the bucket, only the numbers are sort of backward. Higher ISO means a smaller bucket. Let me explain.
If you’re old enough, you may remember purchasing film for your camera in speeds of 100, 200, 400. The higher the number, the better that film performed in low light. That’s the same with ISO. The higher the number, the better the camera performs in low light. It takes less time to “fill the bucket” with light. So you can still have a suitably quick shutter speed in low light.
We will discuss the ins and outs of each function in detail later, but for now, know that a lower ISO is preferred.
Aperture = the hose
I don’t know why, but learning about aperture was the most eye-opening, game changing thing for my photography! I take that back, I do know why, and I’ll get to that.
Back to the bucket. Imagine that you have a pretty big bucket and you don’t want to take all day to fill it. You have the option to fill it with a normal-sized hose and faucet, a straw-sized (diameter) hose, or hose as big around as your leg.
Obviously, the larger hose would be faster! Even with a giganto bucket, it would only take a few seconds to fill!
The aperture is the diameter of the hole that lets light in to your camera. Simple as that.
It does some amazing things too like controlling whether you get creamy backgrounds or sharp-pointy sunflares! Learning to control aperture meant I could get creamy backgrounds and shoot in lower light conditions without flash most of the time.
I heart aperture.
We’ll get into the details of aperture in another post, but for now, I’d say stick to lower apertures. This is really personal preference, but most portrait photographers prefer smaller apertures. Aperture is measured in what we call f-stops ranging from as low as 1.2 to as high as 22. Higher apertures mean a smaller opening.
So perhaps that’s the real secret: Photography is Backwards World.
Small shutter speeds have big numbers (1/2000)
Big ISO takes less time to “fill” with light.
And small aperture means a big hole.
Just wait until we talk about Kelvin. I still get backwards on that one!
Putting it all together:
The way these three things work together is called the exposure triangle.
Let’s say you’re outside on a sunny day shooting an amazing landscape full of details. You want to get all the details in which means you’ll need a pretty high aperture. Higher aperture means smaller hole, less light. Nothing is moving really, and you have a tripod, so you can use a slower shutter speed. With the bright sunny day, you’ll be able to use the lowest ISO!
Let’s say you are indoors, taking a photo of your child in their messy room. We want to blur the background and allow more light since it’s pretty dark indoors. Lowest Aperture we can get.
We want to keep the shutter speed pretty fast since we are hand-holding the camera and the child will inevitably move. We’ll need a pretty quick shutter speed.
With low aperture and quick shutter speed, we may not be able to get enough light into the “bucket” so we need a smaller bucket–a higher ISO–to properly expose the photo.
Let me know if that’s clear as the water coming out of a hose or did it come out like the water after the car wash?