Understand Exposure in 6 Seconds

Episode transcript:

Confused by how aperture and shutter speed affect your exposure? Stick around and be demystified!

[opening credits]

Hey all, welcome to Professional Photography Tips. I’m Josh Cripps and here’s everything you need to understand about shutter speed, aperture, and exposure.

Still confused? I don’t blame you, so let’s take a closer look. You can think about every photo you take as a cup being filled up with water. The cup is your image, and the water in this case is light.

Now there are a lot of different ways to fill this cup up. I can open the faucet all the way up; the water gushes in and the cup fills up quickly. Or I can just barely crack the tap; the water dribbles in and the cup takes a much longer time to fill up.

And this, my friends, describes *exactly* the relationship between shutter speed, aperture, and exposure. Open your aperture all the way wide, light streams into your camera and your image fills up quickly, giving you a short shutter. Scrunch your aperture down to a pinhole and it takes awhile for the light to fill up your photo, resulting in a long shutter speed.

Of course, that assumes you are filling your cup up with the exact right amount of water, because it’s also possible to overfill your cup. Open up the faucet too far for too long and sploosh: your cup runneth over. This is what happens when you over-expose an image: too much light let in for too long. Conversely, you can underfill your cup: a wee little stream for a short time means you just have a little puddle in the bottom. I mean, you can barely see if there’s even any water in there. That’s underexposure: too little light splashing around in the bottom of your image.

And that’s it: everything you need to understand about the relationship between shutter speed, aperture, and exposure. Pick a wide open aperture? You’ll need to choose a short shutter speed so that your cup doesn’t overflow. Want a very long shutter? Well then you better cinch that aperture down to get the right exposure.

At this point you’re probably thinking, well that’s great, but how do I know exactly which shutter speed and aperture to pick? I mean, if there are all these different, somehow equivalent ways of filling my cup up, why should I choose one shutter speed over another, or one aperture over another? You may also be wondering where ISO fits into this mess. Well we’ll be looking at all of that in our next few videos, so be sure to subscribe. And don’t forget to check out my website joshuacripps dot com for landscape photography, tutorials, workshops and more. Until next time, have fun and happy shooting!

A Cold Day in Church

Cathedral Peak Yosemite Winter Sunset

Behind the scenes of this photo


Taken from a granite outcropping overlooking Cathedral Peak, Yosemite National Park, on May 3rd, 2014

On the first day Tioga Pass opened this year I found myself loading up a bear canister with salami sandwiches and chocolate for a hike into Upper Cathedral Lake. No one was really sure what the trail conditions would be like, but the guy at the wilderness office in Yosemite Valley estimated the snow on the trail to be “patchy but manageable.” And it totally was, for about 1.5 miles. After that the snow cover became 100% and since I neglected to bring snow shoes I enjoyed postholing for the next few miles through deep snow drifts.

But even at the staggeringly slow pace of one mile per hour I eventually reached the lake, just after sunset. I missed the opportunity to shoot that night, but fast forward 24 hours and I found myself on this granite outcrop between Upper and Lower Cathedral Lakes. I had a grand view of the majestic Cathedral Peak and the dramatic clouds beyond. And although this photo doesn’t show it, a biting wind was blowing, dropping the perceived temperature into the low teens. Still, it was an uplifting experience!

View more beautiful Yosemite photos.