ISO and How to Use It

The technical name for ISO is International Organization of Standardization, which honestly doesn’t seem to make of ton of sense to me personally. However, ISO is basically a mix of the quality of your image VS the camera’s sensitivity to light. A lower ISO will result in a higher quality image with better colors and sharpness all while letting more light into the lens.

More ISO, More Grain

Shooting with a higher ISO will result in more grain, less vibrancy in the colors, and typically a softer image. This will also allow your lens to be MORE sensitive to light. You should typically try to shoot with a lower ISO. However, on higher end cameras, a high ISO isn’t too much to be scared of. Modern tech is allowing us to shoot at higher and higher ISO’s while maintaining a stable image.

High ISO= More grain and a more sensitive image sensor, resulting in a lower quality image.

This image has a very high iso, causing a ton of grain. Still a useable image though.

Low ISO = Less grain and a less sensitive image sensor, resulting in a higher quality image.

what is ISO
Notice that this image isn’t using a super high ISO, avoiding grain showing up in the image.

When to Use a High ISO

If a high ISO causes an unflattering image, why even bother? First off, like anything with photography, we will want to avoid the extremities of any of these settings. Secondly, a shot with a little grain in it is way better than the shot that doesn’t exist. Sometimes this really is the only option you have. 

Alternatives & Fixes

This is typically when we will want to use a flash, if permitted in the location we’re shooting. Flashes will allow you to keep your ISO lower, while giving you more light shaping options that we will cover later. Another fix for when you just can’t use a flash or don’t have one on you is noise reduction in Adobe Lightroom. This is typically a last-stitch effort and should be used in moderation. Just be careful to not use the built in noise reduction in the camera. This noise reduction is baked-in and should be avoided since we can add it later if desired. The last thing you want to do is have an image that you can’t fix.

Off-Camera Lighting

As mentioned above, you can use flashes to keep yourself from being pushed into the crazy high ISO world. Though this isn’t always a great solution, it works more than it doesn’t. If you can take the time to learn about off-camera lighting it will change your life. This will allow you to get images that other people are too scared to even try. All while keeping your ISO super low.

By using a speed-light off-camera, I was able to capture the fireworks in the background of this image. As an added bonus though, the off-camera light enabled me to expose for my couple. This creates a very interesting dynamic to the image.

Some Camera’s Are Just Better in Low-Light

Some camera’s like the Sony a7sii or the EOS R are simply better in low-light situations, those pesky high ISO situations. Part of the reason for this is that they are full frame cameras. A full frame sensor can handle low light a great deal better than a crop sensor. We will cover that in detail in a later article though. Check out my review of the EOS R and the Sony a7Rii. The a7Rii is another low-light monster of a camera.

This Information And More Featured In Photography 101.

This portion of the exposure triangle and understanding its magnificence, is a small portion of my Photography 101 Course that you can, for a limited time only, be a life-time member of for only $45. That’s a steal, and so much more effective than buying books. This video series is continually growing and I’d love for you to be a part of our tribe! Learn more about the course by checking out this page.


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