Welcome back to The Very Beginning! In this series, we have been exploring the fundamentals of photography, from understanding aperture to mastering shutter speed. Today, we’re diving into the last piece of the exposure triangle, ISO. Once you understand these settings individually, we’ll discuss how to put them all together to create a properly exposed image. So let’s dive in!
ISO (pronounced either “ice-oh” or “I-S-O”) measures the sensitivity of your camera’s sensor to light. It’s derived from film photography when different film stocks had varying levels of sensitivity to light. In the digital world, it serves a similar purpose but with a twist – it amplifies the signal from your camera’s sensor to make it more or less sensitive to light.
ISO settings are expressed as numbers like 100, 200, 400, 800, and so on. Here’s what you need to know:
As I mentioned earlier, the higher the ISO setting, the more digital noise (think of static on a TV) you’ll introduce in your images. It’s hard to see on the tiny screen on the back of your camera, but you’ll definitely notice it on your computer screen. To mitigate noise, I suggest using the lowest ISO setting that allows you to achieve the desired exposure.
There is some good news on this front. As camera technology has improved, so has the ability to push to higher ISO settings without over-doing the noise. On my mirrorless Canon R6, as long as I get the entire photo exposed properly so I don’t have to increase the shadows dramatically in Lightroom, I can push my ISO to numbers I never would have dreamed of on my DSLR. On the DSLR, I avoided going above 1600 at all costs. However, on my R6, I’ve shot as high as 20000 and have been able to maintain reasonable detail without too much noise. (See example below.) This was only possible because I properly exposed the image in camera and didn’t have to brighten it significantly in post-processing.
Noise becomes most apparent in the shadows of an image when you brighten them in post-processing. (See example below, especially the boxed area that was particularly dark straight-out-of-camera.) To avoid this, it is crucial to expose your image properly in camera. If you can’t justify increasing your ISO any more because of noise, try decreasing your aperture and/or shutter speed if possible to let in more light. If you’re maxed out on all these settings, then it may be time to learn flash. But that’s a blog post for another day!
ISO is the final piece of the exposure triangle that controls how sensitive the camera’s sensor is to light. You want to keep it as low as possible to minimize noise, but that requires you to know your equipment. I would suggest playing around with your ISO and getting a feel for how high you can take it while keeping the amount of noise where you’d like.
Up next in The Very Beginning, we’ll look at one more manual setting that I like to use, Kelvin. This is the manual approach to white balance. While it doesn’t impact overall exposure, getting it right in camera can help you make other adjustments more easily. Plus, it makes editing faster!
If you have questions or need guidance along the way, please let me know in the comments below or send me a DM on Instagram. I’d love to chat!
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