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)
ISO 1600 (Native Camera ISO)
ISO 3200 (Native Camera ISO)
ISO 6400 (Native Camera ISO, Highest I prefer to use)
ISO 12800 (Native Camera ISO)
ISO 25600 (Native Camera ISO)
ISO 51200 (Highest Native Camera ISO)
ISO 204800 (Non-Native Camera ISO)
Above is a series of photos from my camera after performing this test myself. I chose to use a color calibration chart as it should be fairly easy to track noise and color degradation with the increase in ISO. I started with the native range for my camera's ISO, but also did the extreme low and high range that the sensor can be pushed to. In this case 50 and 204800 ISO. I do not recommend using ISO settings outside of your camera's native range, however. From the images above you can see that the 204800 setting produces images that are completely unusable. At a setting of 50, it almost appears as if the image is slightly softer than at 100, and as an ISO of 50 is a loss of an entire stop of light, I will not ever be using this ISO setting either.
After inspecting the images of the native ISO's, you can see that you can get quite high before your start to see significant artifacts without pixel peeping. This is an important observation to make as the photographer is far more likely to notice this sort of image noise than a customer due to the concept of pixel peeping. Normal people tend to not look at images in detail or close up. With this in mind, I still looked at the images zoomed in to make my final decision on what my maximum usable ISO should be. Surprisingly, I would be willing to push it out to an ISO of 6400 before the amount of noise makes the photo unusable for what I do. Although, I would still prefer to try and make an image work within an ISO of 3200 if possible. Still, that gives me a whole 5-6 stops worth of exposure adjustment with acceptable image quality to work with which makes my camera much more flexible than when I locked in on ISO 100.
ISO 100 (Zoomed In)
ISO 3200 (Zoomed In)
ISO 6400 (Zoomed In)
I included three photos that are zoomed in nice and close on a rectangle of 6 of the color squares for easier comparison above. You can see the difference between 100, 3200, and 6400 ISO, but even at 6400 ISO it can be a subtle difference until you see the noise. The colors that show the noise/color fading the best are the darker green square in the bottom right and the purple color square in the top middle. Here you can clearly see the increase in noise, and the slight fading of the color overall. While noticeable in these sample photos, it would be more difficult to tell in a landscape composition. The study set-up that I used to produce these sample images was intended to make it as easy as possible to see the differences between the ISO settings.
You can now see how bringing the ISO on the Nikon Z6 camera all the way up to 6400 can be more than acceptable in many shooting situations. Just for fun, you will see ISO 50 and 204800 compared to ISO 100 below for the same zoomed in images as above. ISO 50 does not look bad, but again I think it is a little softer looking than the native 100 ISO. 204800 looks even more like a hot mess zoomed in!
ISO 50 (Zoomed In)
ISO 100 (Zoomed In)
ISO 204800 (Zoomed In)
I wanted to show a comparison to another camera, so I took the same photos using my old GoPro, but I will not include these photos as I remembered why I made the switch to a regular camera after loading the pictures up on my computer. The ISO 100 photo on my GoPro looked as hazy as the ISO 12800 on my Z6, and it just got worse from there. Not to mention the fish-eye lens and that the ISO cannot go higher than 3200 on the GoPro.
Now to get back to why this is important. Sure, you can often pull out your tripod to help keep your ISO down and use your shutter speed to make changes to your exposure, however there are many situations where simply doing this will actually yield a softer image. Namely, any scene that has motion in it. Whether it be a windy day and the trees are blowing around, or if you have moving water from a stream, river, waterfall, creek, etc. you cannot just drop your shutter speed to brighten the image and expect it to come out sharp because your ISO is at 100. Another situation that warrants increased ISO to get sharper images is wildlife photography, or any situation where handheld usage of the camera is required.
I recently tried to photograph a hummingbird while I was on a lunch break at work. It is commonly known that a hummingbird's wings beat extremely fast and to get a good shot of it you need a shutter speed of around 1/2000th of a second or faster. You can drop your aperture a little bit to compensate for the loss of light this will bring, but not enough to always compensate without damaging the depth of field fully, in which case you need to bump up your ISO to get a sharper image. In my attempts I tried too much to balance shutter speed and aperture to keep my ISO low and it resulted in a poor image of the bird’s wings while in flight.
1/1600 sec at f/8.0, ISO 400, 200mm (NIKKOR Z 70-200mm f/2.8 VR S)
For this shot I should have increased the ISO to around 800-1600 to both brighten the image a bit and to be able to increase the shutter speed even more. Some shooting conditions require that you use all the tools at your disposal to capture the best shots. But my past failures are lessons for the future, and for others so that mistakes can be avoided in the future.
I did not want to end this informative post off without leaving a good quality photo for my readers. After all, I am in the business of trying to produce quality landscape photography! Below is a work in progress photo from one of my more recent hikes here in the great Pacific Northwest. It was a fallen tree, mossed covered convergence of multiple streams with fast moving water. It was a beautiful area and I in addition to grabbing this photo, I also took a short break to enjoy the scenery and sounds of the flowing water. (On a side note, I have been taking short 30 second clips of waterfall's and streams with the idea of making soothing screensavers or ASMR nature videos. Let me know if you think this is would be interesting!)
As this spot I was at was in a fairly thick forest, the scene was naturally darker than other areas of the hike even during the middle of the day. As the water was moving quickly it required playing around with the shutter speed and ISO to get a good amount of motion in the water. Luckily, the shutter speed I felt looked the best for this scene was low enough to not need to increase the ISO significantly, and the aperture was set to 10 to try and keep the whole scene in focus without needing to do a focus stack.
1/15 sec at f/10, ISO 500, 24mm (NIKKOR Z 24-70mm f/2.8 S)
In summary, don't be afraid to push your cameras ISO setting up while out in the field. It might actually improve the quality of your images. The best thing you can do is be prepared and understand the limitations of your equipment by testing it out at home. I hope you found this post informative and enjoyed the content. I wish you an awesome day, and until next time!