As Nikon’s entry-level DSLR, the D3400 doesn’t have as expansive an ISO range as some of the high-end models. Some of those have ISO ranges that go all the way up into the millions. But the D3400 still has a relatively broad range, from 100 through 25,600.
An ISO of 100 means that the sensor’s light sensitivity is low. That’s a good setting for shooting in bright conditions. An ISO of 25,600 means that the sensor is very sensitive to even small amounts of light, making it a good option for night or low-light shooting such as indoor or night photography.
The catch with ISO, of course, is that the higher numbers also bring the risk of degraded image quality, which is why photographers’ first instinct is usually to use the lowest ISO they can get away with. With high ISOs, the first issue is noise and grain in the photo. The second issue is that at very high ISOs the sensor doesn’t respond as well to color, so you can get washed out and harsher colors. How much of a problem those things are is entirely subjective and depends on what you’re shooting and the look you’re going for.
The latest cameras are getting very good at combining high ISOs with low noise and good color reproduction. But there still might be limits beyond which the results might not be a good fit for what you want. If you’re shooting purely for your own enjoyment, then you have a lot more wiggle room and can probably put up with a lot more image noise than if you’re shooting for someone else. For instance, if you’re shooting for a stock agency, they can be notoriously picky about any visible image noise when viewing the image at 100 percent.
So the shots below are designed to give some practical examples of the D3400’s performance at different ISO settings. And related to this, I’ve also put together a quick guide on how to change the ISO on a Nikon D3400.
How These High-ISO Examples Were Shot
There are no fancy setting settings here-deliberately so. To get a consistent exposure across the frames, I mounted in on a tripod and put it on Aperture priority setting. So the aperture remained constant, with the shutter speed adjusting to compensate for the ISO I was setting. So you’ll see that the overall visual exposure remains pretty constant across all the images, but you’ll also notice that the low-ISO ones used a longer shutter speed (hence the light streaks). And they’re taken with consistent natural light.
By default, the Nikon D3400 applies noise reduction to high-ISO photos in camera, and I wanted to remove that complication. You can turn that setting off or change its aggressiveness, but by default it’s turned on. That in-camera noise reduction doesn’t, technically, affect RAW images as such, just JPGs. But it is applied to the JPG preview images that are embedded into the RAW files and that are the versions you see when you view the image on the back of the camera. Those are also the initial versions you’re seeing when you import the images into apps like Lightroom or PhotoMechanic. If you open a RAW file and see obvious effects of in-camera noise reduction, that’s why. To bypass that, I’ve made sure to regenerate the images below directly from the underlying RAW file. That was done in Lightroom, and I disabled Lightroom’s noise reduction and sharpening functions. No other editing or tweaking has been applied.
ISO Sample Images from the Nikon D3400
The effects of image noise are much better viewed zoomed in to 1:1. To open each image as a full-resolution version, you can click on them below.