Elements of Exposure: ISO

Hello again! :) 
Today we’re kicking off a mini series of posts called Elements of Exposure.

Exposure is, at its simplest, how bright or dark your image appears. Nailing your exposure is the first step towards successfully “taking a good picture.” Figuring out all of these settings can be intimidating, but I’m here to help break down all the Elements of your Exposure: ISO, Aperture, and Shutter Speed so that you feel comfortable understanding how each of these affects your images.

Today we’re going to start with ISO. In Search Of a definition? Don’t worry about what the letters stand for, just remember ISO = How sensitive your camera sensor is to light. If the last time you were using a camera was when you put film in it, then this was a decision you made when you purchased your film at the store. The higher the number, the more sensitive your sensor (digital, or film) is to light. You were probably using something like ISO = 100 for full sun and ISO = 400 for scenarios where you expected there to be less light… these numbers still hold true :)

Here are a couple ways to conceptualize how this works. Pretend you’re out on the beach using your trusty metal detector (a standard household item, yes?). As you walk along, if your detector is struggling to find metal, you’ll crank up a dial that makes it more sensitive. Another metaphor is your grandma’s hearing aid. When she turns it up, she can now hear you, even though you tend to be softspoken! However, at this higher setting your voice is more likely to become distorted. As a hearing aid is designed to detect and amplify sound, your camera’s ISO setting is designed to do the same for light. Turning up your ISO is like turning up the volume on your hearing aid, or the sensitivity on the metal detector.

The drawback to increasing your ISO sensitivity setting is that it directly affects the quality of your image. We can all picture a really grainy photo or a static-y screen - this is called digital “noise”, and it’s not cute. The higher you turn up your ISO, the more noise your image will have. Take a look at how these two images compare…. the same set up was shot at ISO 100 and ISO 6400 (pro note: the other two settings that we’ll talk about later compensated to keep the same brightness, if you had ONLY changed the ISO these two images would have drastically different levels of brightness. This is relevant if you shoot in Manual exposure. If this statement just confused you, feel free to ignore it.)

From a distance these two look images might not look too different, but if you look a little closer in the shadows (which is where noise will lurk and attack the strongest) you’ll be able to see the difference. Here you can really see how the shadow areas at ISO 100 look nice and smooth and the shadow areas for ISO 6400 look pretty gritty and grainy.

But sometimes desperate times call for desperate measures, and if you’re starved for light it’s better to crank up that ISO than to not get a photo at all. You’d be surprised how dark most indoor spaces really are (your eye tricks you, because your pupil automatically dilates to compensate!). Try to use the lowest ISO possible for whatever your situation, no higher than 3200 if you can!

Stay tuned for the other two posts in this series on Aperture and Shutter Speed, or if you wanna dive in right away check out my online course, Camera Bootcamp: From AUTO to WOW ! To receive my NSP Academy Newsletter, head over to NSP Photo Academy; you’ll get alerted when my newest posts drop AND you can instantly access my exclusive guide, 6 Ways to Start Taking Better Photos Today!!! As always, I love to see what you’re out there creating, so tag me on social using #NSPphotoacademy