With its smaller APS-C sized sensor, it’s hard for the FujiFilm X-T3 to compete with full-frame competitors like the Sony a7 iii, Sony a7R iii, or Nikon Z7. And to be frank, it doesn’t threaten to—if you’re putting a priority on low-light shooting, those are hard to beat when it comes to mirrorless bodies.
That said, the cameras in the X-T range have been steadily improving in their low-light performance (the X-T2 is pretty good in this regard too--here are some examples). And even if there are full-frame cameras that perform better at high ISOs, I’ve been impressed with the X-T3’s performance in this area and a little surprised that it comes as close to something as the A7 iii as it does. So I thought it might be useful to post some real-world examples for anyone looking to judge for themselves whether the X-T3’s high-iso performance is up to snuff for what they want and expect.
The X-T3 has a native ISO range of 160 through 12800. If you use the Auto ISO setting on the top dial, it will work within that range (you can also set a lower limit—more on that below).
But you can go higher than 12800 by moving into the extended ISO range of 25600 and 51200 (there’s also an extended option at the bottom end, down to 80). At these settings, it’s moving beyond the native capabilities of the hardware and the image is boosted by software. That’s why you’ll see a momentary flash of the “processing” indicator on screen when you’re shooting and the frames per second between shots slows slightly. You’ll also notice the image quality will drop off markedly, which is why these aren’t enabled by default. Accessing these extended ISOs is pretty straightforward—move the dial to the “H” marking—although it’s not self-evident how to get the 51200 option; I’ve put together a separate explanation on how to enable the maximum ISO setting.
These were all shot as RAW. They were processed in Lightroom, but I haven't applied any extra noise reduction beyond the default Lightroom setting (amount: 40; radius: 1.0; detail: 25; masking: 0). If you're shooting JPG (or previewing the original embedded JPG thumbnail for the RAW file), the X-T3 has some noise reduction tools built in, but I've deliberately bypassed those by re-rendering directly from the RAW data.
You can click on each image to open a full-size version for a closer look, and there's a link in each image's caption where you can download the original RAW file (NB: they're about 56MB each).
Sample Photos Taken at High ISOs with the FujiFilm X-T3
Here’s a more general sampling of various images I’ve shot with the X-T3 at ISOs from 3200 to 51200.
FujiFilm X-T3 High ISO Side-by-Side Sequence
Here’s a sequence I shot at each ISO step to give a sense of how moving up the ISO increments affects image quality.
Here's another sequence:
Auto ISO Settings on the FujiFilm X-T3
When using the Auto ISO setting on the X-T3, you have a few options for customizing how it behaves.
You can set the default sensitivity. The default is the lowest native ISO (160), and in many situations, that's going to be ideal in that it starts at the lowest native ISO and only goes higher if it needs to. But there are also situations where you might want to make sure it's using a high ISO.
There are three presets (Auto 1, Auto 2, and Auto 3) that you can set to maximum sensitivity limits. So, for instance, if you're shooting portraits and don't want it to go over, say, ISO 800, you could set that as the maximum for Auto 1 and use Auto 1 when shooting portraits. But if you want to switch to shooting run and gun low-light street scenes, you might want to set Auto 2 to something like ISO 6400.
You can also designate the minimum shutter speed, including with an Auto function that is based on the focal length of the lens. One thing to note, though, is that if you set the minimum shutter speed manually, it isn't a hard floor. That is, the camera will override it if the image is still underexposed even when using the maximum ISO that you've set in the Max Sensitivity setting.