Updated: Apr 2
ISO is a touchy subject for many photographers, new and hobbyist alike. There is a common conception floating around that to get the best photos that you need to keep your ISO set to the lowest setting that your camera natively works on, in most cases that being 100. Being 100% transparent, until recently I used to fall into this category of photographer that used ISO as purely a last resort option to correct for image exposure issues out on the trail. This change has been brought about due to spending a lot of time recently looking for waterfalls to capture. We will come back to this particular situation later, however.
To quickly explain, ISO is an abbreviation for International Standard Organization and simply put for the function in photography, is a relative measure of the camera sensors sensitivity to the incoming light. Most cameras allow for making adjustments to this value to change how sensitive the sensor is to measurements of the light that is allowed through the lens based off of the shutter speed. If you would like to learn more about the exposure triangle in photography, make sure to check out my blog post on it here.
Graphic depicting the introduction of noise with increasing ISO
This camera setting is often associated with sensor noise being introduced into images. A graphic depicting a simple example of this is shown above. While this is true, that taking the cameras ISO setting above its lowest base setting begins to introduce noise, this is not always that big of a deal. With modern camera sensors, specifically mirrorless cameras, the ISO settings that you can use before significant, or even noticeable at that, amounts of noise begin to set in has been improving drastically. With this brings the onset of new opportunities in using your camera while out in the field. You do not always need to rely on your tripod and shutter speed to set your image exposure.
But then brings the question of how much ISO is too much? Well, this question really must be answered on a camera-by-camera basis, as all sensors act differently. If you regularly read my blog, you might know that my first camera that I used as a hobbyist photographer was a little GoPro Hero 6 Pro Black. This camera is an excellent little camera for price, durability, portability, and peace of mind while out adventuring. Especially if most of the content is for personal use or social media. This camera's sensor is way more sensitive to ISO changes than my daily driver camera, the Nikon Z6. This is the camera that takes most of the photos that you currently see from me, and I must say does an amazing job for how I use it.
Now, due to me being transparent in indicating that I used to fall into the category of photographers that keep their ISO set at 100 unless absolutely necessary I have recently asked myself these same questions about my camera. The best way to do this is to spend an hour or two with your camera. Simply find a scene with a good mix of lighting and color around the house, set up your tripod, and take a series of test photos using your camera. Start at ISO 100 (or 50 if that is your cameras lowest native ISO) and start stepping it up by each stop level until you reach the highest native ISO of your camera. Adjusting shutter speed, and if necessary, aperture, to keep the exposures consistent for each test shot. Then load the photos up on your computer and start taking a look.
ISO 50 (Lowest Non-Native Camera ISO)
ISO 100 (Lowest Native Camera ISO)
ISO 200 (Native Camera ISO)
ISO 400 (Native Camera ISO)
ISO 800 (Native Camera ISO)