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Fujifilm AUTO ISO Settings: What It Is and When to Use It

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One of the things that has improved my photography was getting over my 2006-era mentality that we still have 2006-era technology.  It’s come so far! 

Ten years ago I avoided shooting over ISO400 because of the noise levels, and that reasoning has somehow survived longer than it should have.  I shot at slower shutter speeds to make this happen.  Many a soft image is due to camera shake.

The truth is, even modern APS-C cameras like the Fujifilm X-T2 & X-E3 are going to give you great images at up to ISO6400, even 12800.  This is often enough for 98% of photographers and is one of the reasons why you should be using Fuji’s AUTO ISO setting.

Note: While the “how-to” is specific to Fujifilm cameras, the concept can be applied to other major manufacturers.  Check your owner’s manual for details.

The Aperture Priority dilemma

Aperture Priority is a popular setting.  You set the aperture to control the depth of field, and then the camera determines the correct shutter speed for proper exposure. 

Most “I’ll set my own ISO, thank you very much” photographers leave the ISO set to something low to get a “clean” image.  Holdouts like me.

The problem is, if you’re not careful, the proper shutter speed could be too low.  This can result in unwanted motion, both in your subject and in the camera.


This is where the Fujifilm AUTO ISO setting and current technology saves the day.

jasper national park
This storm moved in FAST, dropping the ambient light significantly. Thankfully, AUTO ISO kept my minimum shutter speed fast enough to mostly freeze the snowflakes and freezing people, increasing the ISO to 1600 to do so. Aperture Priority @ f/8.

Here’s the video version if you’d rather watch this:

What is AUTO ISO?

Just like it sounds, AUTO ISO lets the camera determine the ISO to give you a proper exposure, within the range you set. 

But the moneymaker is also being able to program a minimum shutter speed to get a pseudo-shutter priority – increasing image sharpness.

The current generation of Fujifilm X cameras allows you to have three different custom AUTO ISO settings.

fujifilm auto iso setting
Old school: The Fujifilm X100F has a pull-up sleeve to set the ISO within the shutter dial, just like my ancient Pentax.

How AUTO ISO works

With both ISO and Shutter dial in “AUTO”:

  1. Your camera will first go to the lowest ISO you programmed and adjust the shutter speed for the proper exposure.
  2. If your programmed minimum shutter speed isn’t slow enough, the camera will then raise the ISO to get the right exposure, up to your programmed maximum limit.
  3. If it’s still underexposed, the camera will then slow down the shutter speed below the minimum you’ve set to get the proper exposure.

EXAMPLE: You set an ISO range of 200-3200 and a minimum shutter speed of 1/250 second.  If the image will be underexposed by one stop at 1/250 and ISO3200, the camera will automatically lower the shutter speed to 1/125 second while maintaining ISO3200.

With ISO in “AUTO” but the shutter dial set to a specific speed (not “A”):

The camera will hold that shutter speed and operate within your programmed ISO range. 

This could result in underexposed images if the ISO isn’t high enough and/or the shutter isn’t slow enough.

low light image
In this AUTO ISO setting, I had a minimum speed of 1/125 and maximum ISO of 6400. With low light, the camera captured the exposure at ISO6400 and 1/15 second (exposure compensaiton -4).  Shooting in burst mode ensured a few sharp images.

When to use AUTO ISO

I use AUTO ISO most of the time now as I become more comfortable with higher ISO values

The only time I don’t use AUTO ISO is when I’m maximizing the capabilities of my camera for full artistic expression. 

Long exposures, for example, need to be as “noiseless” as possible.  I’ll lower the ISO as much as I can while staying within the bounds of the shutter speed and aperture I need to use for my vision.

dades gorge
For this image, I needed a 2-minute exposure and wanted to keep the ISO low, around 200-400. I made it work with an aperture of f/4.0. This is where you’re better off shooting in Manual.

How to program Fujifilm AUTO ISO settings

  • You can set the ISO range along the gamut of the base ISOs (typically 160-12800).  You cannot program expanded ISO ranges.
  • The minimum shutter speed can typically be set from 1/4 second to 1/500 second.
  • You can also set the shutter speed to AUTO in the AUTO ISO programming menu.  In this case, the camera sets a shutter speed approximately inverse to the lens’ focal length (i.e. a 35mm lens will have a minimum speed of around 1/40 second).  This is a great technique for minimizing camera shake.  It also works with Fujifilm zoom lenses as you change the focal length. But keep in mind it may not be enough to freeze motion in front of you.  This is only advisable for still life.

There are so many different ways that you can utilize the Fujifilm AUTO ISO settings.  I’m not going to tell you that my way is the correct way, but rather just tell you how I have it set and my thought process behind it.

1) Think about which ISO & shutter speed settings make sense for your style

The needs of a landscape photographer will be different than a street photographer.  But this is how I do it now after some trial & error:

  • AUTO1: My primary travel-type images require a steady shot and freezing everyday motion.  I don’t mind a little grain.  I’ve set the ISO range of 160-6400 and a minimum shutter speed of 1/200 second.  I use this for portraits too.
  • AUTO2: When I step away from people & other moving objects I go to AUTO2, like for landscapes and still life. I’ve set the ISO range to 160-1600 and a minimum shutter speed of AUTO to base shutter speed on my focal length (1/40 on my X100V).  I’m only concerned about minimizing camera shake in these situations, and I benefit from a slightly cleaner image with the lower ISO.
  • AUTO3: My “emergency, gotta capture the scene” dial.  I’m looking for a sharp photo and don’t care about the noise level because of the urgency to capture.  ISO range is 160-12800 and minimum shutter speed 1/125 second.

Once you have an idea of how you want to program it, it’s time to program it.

2) Program AUTO ISO settings in the menu

Program Auto ISO

Each Fujifilm X camera is slightly different, but more or less the same.  In the menu, go into the Shooting Settings and then find ISO AUTO SETTING. 

From there it’s fairly self-explanatory.  Set the

  1. default (lowest) ISO setting,
  2. maximum ISO setting, and
  3. minimum shutter speed.

3) Program your AUTO ISO function button

You can program any of the custom buttons to access your Fuji AUTO ISO setting.


I used the front command dial (on the front of the camera below the shutter button) on older cameras like the X-T2, X-E3, and X100F. In the Button/Dial Settings, set COMMAND to ISO DIAL SETTING, or ISO DIAL SETTING (A) to COMMAND, depending on the camera.  Rotating the front command dial now allows you to immediately switch between AUTO1, AUTO2, and AUTO3.

Newer cameras don’t allow you to do this anymore and I really miss that feature! If you have an extra custom button to spare, hold the DISP/BACK button and assign ISO AUTO SETTING to the button you wish to use.

Or, at a minimum, at least put AUTO ISO in your My Menu so you can quickly get to it after pressing MENU.

The X-E3 also allows you to set 3 AUTO ISOs for each Custom Setting.  These can be programmed from Image Quality Setting -> Edit Custom Setting.  By default these follow the three settings you’ve programmed in the Shooting Settings.  You may override them for each custom setting.

Overriding Full AUTO ISO in a pinch

fujifilm auto iso
Override the AUTO ISO shutter speed by simply rotating the shutter dial out of “A” (right of viewfinder).  The ISO dial is on the left.  X-T2 pictured.

There are times when you’ll want a slower shutter speed to show movement and will need to adjust quickly.  This is one of the beauties of using the Fuji AUTO ISO settings in concert with their awesome ergonomics.

Leave the camera in AUTO ISO but rotate the shutter dial to the speed you desire (1/30 or whatever you need for movement).  No menus, no fidgeting around…it takes a quarter of a second.  Now you’re in both Aperture and Shutter priority, letting the camera adjust ISO to get the exposure.


In the above example, I was in and out of buildings, shooting in AUTO ISO so that I’d maintain a fast enough shutter speed to freeze movement as I bounced between lighting situations. 

But as I watched this scene, I wanted to show a subtle movement to put the viewer there.  I quickly dropped my shutter dial to 1/60 and snapped this photo during the action. 

Before going back outside I put the shutter dial back in AUTO to give me the minimum of 1/200 that I had programmed for sharp images in the AUTO ISO menu.  I was now back in Aperture priority and a pseudo-shutter priority with the Auto ISO.

The final step for using Fujifilm’s AUTO ISO settings

Practice.  And then practice more.

Go shoot in all sorts of scenarios and get used to switching between the three different AUTO ISO settings if you’re using them.  Know which settings are best for different scenarios.

You don’t want to be in AUTO2 for shooting a landscape then miss a spontaneous portrait opportunity because you were at 1/30 second when your subject moved.  Get to the point where you go to the proper setting without needing to think about it and your photography will definitely improve!

How do you have AUTO ISO set up?


Wednesday 22nd of September 2021

This entire article was extremely extremely helpful to someone like me who is slowly learning my X100F. Excellent excellent walk thru. So glad I found this.

One question that you may have answered - I seem to notice that in Auto ISO mode (with Auto ISO, auto shutter speed, and lens wide open at f/2), shooting in really dark conditions (for experimentation purposes), where I guess underexposure is unavoidable - the camera will still drop to a slower shutter speed than the minimum you have set? It seems like it's not a hard lower bound - is that correct?

John Peltier

Wednesday 22nd of September 2021

That is true - your ISO limits are “hard stops” but if the camera still needs a slower shutter speed to get the exposure that you’re asking for, it’ll do it.


Thursday 3rd of June 2021

Thanks much for this very helpful and detailed explanation. I bought my first ever digital camera last year, an xt3, and have been struggling to get the settings right. My last cameras were old Nikon and medium format cameras and the simplicity of them is shocking compared to what's possibly on my xt3. I mostly shoot my dog and landscapes but have been struggling with action shots. But after reading this I've got a much better grasp of what I need to do. Thank you much! Also, I loved your photos of Morocco. We visited there years ago and it's such a photogenic country!


Friday 20th of August 2021

Great article. When I use auto ISO on my X-S10 the scene through my EV always shows as the highest ISO value and only changes when I half press my shutter release. This makes it difficult to set my exposure. Is there a setting I am missing that would make it preview the scene as is without half press?

John Peltier

Thursday 3rd of June 2021

Yeah it's amazing what this one little setting can do for your photography! Cheers.


Friday 21st of May 2021

Just want to say I appreciate the explanation of how minimum shutter speed of AUTO has an algorithm to look at the focal length of the lens and sets the speed to the inverse of the lens. That's the rule of thumb I always use and to know my Fuji does that automatically is a comfort.


Friday 22nd of January 2021

is this feature also available for the movie mode? like it said, i love aperture mode for vlogging. yet the iso sometimes doing crazy push up to 12k when they find a rather darker area in bright sunny day.

from x-t4 user

John Peltier

Friday 22nd of January 2021

Unfortunately, no. You can set the camera to Auto ISO but it's not programmable in Movie mode. If you're having that problem on a bright sunny day and the light isn't changing, just record in manual mode. Set your aperture for desired depth of field, set your shutter speed to twice your framerate, then adjust your brightness manually with the ISO knob.


Saturday 17th of October 2020

Hi John I just bought a new X-E3 and obviously now I'm in the process of setting all things up. Your article is very helpful but I came across with one problem so far. My ISO settings H (25600/51200) and L (100/125/160) are inactive (in grey colour) so I can't choose them for any of the Auto ISO modes. This is the same with Fn button which I dedicated to ISO setting (the above ISO values are inactive). Do you have any idea why is that. I set my camera for Aperture Priority. I think that somewhere in settings I set something that disabled these options but what could that be ? Thanks in advance Piotr

John Peltier

Thursday 22nd of October 2020

Hi Piotr, sorry for the late reply, my X-E3 was in my studio and I just got back to it. You'll be unable to select any of the expanded ISO settings (100, 125, 160, 25600, 51200) for AUTO ISO since the method this ISO uses is different than the "standard" camera ISOs. This is true for all Fujifilm X cameras, at least all the ones I've owned. If you're still unable to select the expanded ISOs in regular camera operation, I don't know why that would be. I changed some other settings around I thought might affect that and couldn't find anything. If you're still unable to select those values in regular operation, all I could recommend is doing a "set-up reset", found in the User Setting menu.