Photography 101: Mastering Your ISO
In the days of film photography, rolls of film came in various sensitivities. The more sensitive the film, the less light was needed for a proper exposure. This allowed for faster shutter speeds or smaller apertures, giving photographers more creative control. However, shooting with both low and high ISO values have its pros and cons.
With digital sensors, ISO still refers to the sensitivity. The advantage of digital sensors is that you can adjust it with every shot. Previously, you weren’t able to adjust your ISO until your entire roll of film was finished. This made the decision to choose a particular ISO a bit trickier.
Grain/Noise
Higher ISO values let you shoot with faster shutter speeds and smaller apertures, but they also introduce more grain/noise. Grain appears as speckles in a photo where the sensor struggles to process light. This can lead to incorrect colors, loss of detail, and reduced sharpness. Therefore, balancing aperture, shutter speed, and ISO is crucial for the best image quality.
As technology advances, digital sensors are able to handle high ISO settings better and better. Where I would shoot at a maximum ISO of 1600 on my Nikon D5100 (2011), I would have no problems pushing it to ISO 25600 on my Canon EOS R6 (2020), if I would really need to.
Reading your ISO
Now you understand that both low and high ISO numbers have their pros and cons, it would actually be great to show you a list with ISO numbers, which will help you get a better overview of ISO in your exposure.
ISO value
100
200
400
800
1600
3200
6400
12800
25600
51200
102400
204800
Notice how each ISO number doubles the higher that you set your ISO? Each doubling represents one stop of light. If your camera indicates one stop underexposed, doubling your ISO can achieve perfect exposure.
Getting started
When you are just starting out, it is not the most important to have a camera that handles ISO like the latest and greatest. It is important to understand how ISO affects your images and how this setting can assist you to create the desires results in your craft. Experiment with different settings to see how they influence your photos.
After reading this article, or the articles about aperture and/or shutter speed, you may not fully understand yet how each settings influences your exposure and your final image. That is OK. We are here to learn, and I are giving you all the information, all the technical knowledge, that you could use to better understand the bigger picture (no pun intended).
Everyone starts here. You will make a lot of mistakes, and that is perfectly fine. Actually, that’s perfect! Without making mistakes, we would not understand why something does not work. So, don’t be afraid! Just have fun! And I will promise you, it will only get more fun along the way!
For more essential knowledge on your exposure, check out my articles on mastering aperture and shutter speed.