Questions and Contemplations

Exposure, Illustrated

By Ivoryhut.

First, have you read the previous posts on aperture, shutter speed, ISO, and exposure? Yes? Good. No? Get started, then meet me back here. Don’t need to? Please be gentle, my ego is fragile.

If all the technical stuff still kinda cunfusticates and discombobufizes you, you’re not alone. So I thought I’d share with you an illustration that I first heard back when I was learning about photography and trying desperately to keep track of all the settings in my 35mm camera. Sometimes, an illustration can help make it all finally click in your head. And if it doesn’t help, then at least I got to show you that pretty picture of water from my kitchen sink.

Family guy schedule

This would be a good time to remind you that I’m not an expert. The legal department in my brain wanted to make sure you knew that up front. Thank you.

Okay, let’s get on with the illustration. First, imagine a bucket.

I’m sorry, I know that isn’t a bucket. In my world (and in my folder of photos), my bucket looks like a stone urn with floating flowers. But if you want, you can imagine a regular wooden bucket. Or a nice bright red pail. Or a celadon ceramic jug. Whatever makes you happy.

Now, let’s say that proper exposure is represented by this bucket/urn/pail/jug being filled with just the right amount of water. In this illustration, water represents light. So, allowing the right amount of water into the bucket means we let the right amount of light into our camera sensor to create a properly exposed photo.

Got that?

Now, let’s imagine again that this bucket will be filled using a hose attached to a faucet. Assume also for now that you can change the diameter of your hose, and that the faucet only has an on and off switch. (You’ll have to do a lot of imagining and assuming today. Sorry. You can get back to more exciting daydreaming after this.)

Brace yourself for more symbolism. (Symbolism has nothing to do with embolism. I thought you’d like to know that.) The hose diameter is your aperture, and the amount of time that you leave the faucet running is your shutter speed.

Still with me? Anyone?

Now, to properly fill the bucket, there has to be balance between the two. If too much water pours in and the bucket overflows, then you have to shrink your hose (close your aperture) and/or shut off the faucet quicker (use a faster shutter speed). If there isn’t enough water to fill the bucket, then you’ll need to increase the size of your hose (open your aperture) and/or let that faucet run a little longer (use a slower shutter speed).

I’m suddenly getting a little thirsty and/or a wee bit hungry.

Oh, you’re still there? Sorry, I thought I was talking to myself. I figured I probably would have driven most of you away with this nonsensical talk of buckets and adjustable hoses.

Here it is in action. Let’s say I take a photo, and the photo comes out overexposed, meaning I let too much light in. Or, for the purposes of this overused illustration, my bucket overfloweth.

Ack! Too much water! Need to use a smaller hose, or cut off that tap sooner. But wait, I really want to keep my aperture wide open to get as shallow a depth of field as possible. In other words, I don’t want to use a smaller hose. Time to check the faucet. My faucet, or shutter speed, was at 1/125. I bumped that to 1/1000, so now I’m shutting that faucet more quickly. That means less water pours into the bucket, so I avoid that messy overflow.

Much better, yes? The bucket is happier, too.

Let’s look at another example. This was from a very sunny day in Jamaica, and I had my shutter speed at 1/1000 and my aperture at f8 because there was just sooo much light that morning. Then we headed to a secluded beach, which was much shadier with the trees and the clouds that were drifting by. I saw this woman with the cute little child, and snapped their photo. I was too nervous about being a foreigner photographing a local, so I didn’t have time for any checklist, mini or otherwise.

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