When Does ISO Matter?

Modern cameras have amazing high-ISO capabilities. Back in the days of film, ISO 400 was considered high-ISO by many (including Fujifilm, who designated all their ISO 400 films with the letter “H” for high-speed), and ISO 1600 was ultra-high-ISO, used only out of absolute necessity or by the brave who wanted a certain gritty look. Nowadays some photographers don’t even think of ISO 1600 as a high-ISO setting, and don’t think twice about using it. For many, high-ISO doesn’t really begin until ISO 3200, and ultra-high-ISO doesn’t begin until you go above ISO 6400. It’s really unbelievable!

The real question is this: when does ISO matter? Since modern cameras make such good-looking images at incredibly high sensitivities, when should you start considering image quality degradation? When is a certain ISO setting too high? That’s what I want to answer.

Of course, since this is the Fuji X Weekly blog, I’m discussing Fujifilm X cameras, specifically X-Trans III. This won’t apply 100% to other cameras, but it’s still relevant to some degree no matter the camera make and model. If you are reading this with another camera in mind, take everything said here with a small grain of salt.

I did a little experiment just to better understand all of this ISO stuff. I already knew the answer from experience even before beginning the experiment, but I wanted to see if my instincts matched reality. I captured a few sets of identical pictures, all straight-out-of-camera JPEGs from a Fujifilm X-T20, using ISO 400 and ISO 6400. I made sure that all of the settings were the same between the identical pictures except for ISO and shutter speed. This isn’t 100% scientific, but it’s a controlled-enough test to draw some conclusions about ISO capabilities.

Here are the original pictures:


ISO 6400


ISO 400 – my Velvia recipe


ISO 6400


ISO 6400

There’s not a lot that can be learned by looking at the above images, other than when viewing images on the web the ISO doesn’t matter whatsoever because it’s incredibly difficult to spot the differences even when comparing side-by-side. In real life nobody does side-by-side comparisons, that’s pretty much an internet-only thing, so it would be impossible to tell if a picture was captured using a low-ISO or high-ISO just by looking at it on your screen. We need to look much closer to really gain anything from this test. Below are some crops from the above images.


ISO 400


ISO 6400


ISO 400


ISO 6400


ISO 400


ISO 6400

If you study the color crops carefully, you’ll notice that the ISO 400 images are cleaner, sharper and have just a hair more dynamic range, but the differences are quite small and subtle. You really have to look carefully to find them. With the black-and-white image, the differences are even less obvious, and I actually prefer the ISO 6400 version, as it seems to have a more film-like quality. Looking at the crops clarifies things a little, but what kind of conclusions can we really draw?

My opinion with regards to color photography and ISO is this: if I’m printing smaller than 16″ x 24″ or displaying the pictures on the web, I don’t find any practical difference between base ISO and ISO 6400. Even ISO 12800 can be acceptable, especially if I’m not going to print the picture. If I’m going to print 16″ x 24″ or larger, a lower ISO is better, preferably less than ISO 3200, but it’s not a big deal to use up to ISO 6400. The ISO that I select does not make a huge difference to the outcome of the image, so I don’t worry a whole lot about it. Put more simply, if I print large, it’s preferable but not critical that I use a lower ISO, and if I don’t print large it doesn’t matter at all.

My opinion with regards to black-and-white photography and ISO is this: the ISO doesn’t matter much at all no matter how large I’m printing, and I often prefer (just by a little) high-ISO over low-ISO because it looks more analog. I freely use without hesitation any ISO up to 12800. Thanks to the Acros film simulation, Fujifilm X cameras are some of the best monochrome cameras on the market, and with that film simulation, often times the higher the ISO the better.

These are, of course, my opinions, and not everyone is going to agree with them, and that’s perfectly alright. Find what works for you. Use a higher ISO or lower ISO if that’s what you need for your pictures, because, after all, they’re your pictures. I’m not here to judge your camera setting choices, only to offer mine, which I’m hoping is helpful to some of you. I hope that this article makes sense and clarifies some things regarding high-ISO on Fujifilm X cameras.

Below is a video that I made on this topic:

My Fujifilm X100F Auto-ISO Settings


Fortuity – SLC, UT – Fujifilm X100F

A reader of Fuji X Weekly asked me what my Auto-ISO settings are for the Fujifilm X100F. I realized that I’ve never fully covered this in a post. I’ve mentioned some things here and there regarding Auto-ISO, but never laid it out in one place. So I’ll explain it here and now.

Back in the days of film or in the early days of digital, ISO was critical because things didn’t look particularly good past a certain point. I remember when I considered ISO 400 to be high ISO. I remember that my first DSLR, which I purchased about a decade ago, was only capable of good results to ISO 1600, and any ISO above that looked unpleasant. Nowadays cameras are capable of great results at ridiculously high ISOs. The X100F is good to ISO 12800, which is amazing to me!

Auto-ISO is a great feature. Most cameras have it, and the X100F is no exception. You can set it and forget it. You can worry about more important things since you know you’ll get good results no matter what the camera chooses.

Most of the time I operate the X100F in aperture-priority mode, which means that I set the aperture but let the camera choose the ISO and shutter speed. It’s all situational, and I don’t always do things the same way, but the majority of the time this is what I do because the aperture is what I typically want control of.


Kiki – South Weber, UT – Fujifilm X100F

For the Auto-ISO parameters I set the minimum ISO to ISO 200 and the maximum to ISO 6400. Why not ISO 12800? Because if I use the digital teleconverter, ISO 12800 doesn’t look so great. I can always manually set the ISO to 12800 if I need it with a quick and short twist of a ring on top of the camera.

I also set the minimum shutter speed to 1/125. The camera will only choose a slower shutter speed than 1/125 if it reaches ISO 6400 but needs more light for a correct exposure. I find this to be a good shutter speed for most situations. If nothing in the scene is moving and you use a good technique for holding the camera, it’s possible to get sharp pictures handheld with a shutter speed as slow as 1/15. Sometimes if the subject is quickly moving, 1/125 isn’t fast enough, and 1/250 or even 1/500 might be more appropriate. It’s pretty easy to adjust the shutter to be either slower or faster with a turn of the shutter knob on top of the camera from “A” to whatever is needed.

Auto-ISO is a feature that I rely on extensively, but from time-to-time I manually adjust the ISO and/or the shutter speed whenever appropriate. The auto features work well on this camera, and manual adjustments are simple when necessary because the X100F is well designed for quick on-the-fly adjustments.

To summarize, on the X100F I use Auto-ISO with ISO 200 set as the minimum and ISO 6400 set as the maximum, and with the minimum shutter speed set to 1/125. But I look at each situation and decide if these settings will work, and, if not, I make manual adjustments. I hope this helps.

Fujifilm X100F – Digital Teleconverter + High ISO


I talked about how the Digital Teleconverter on the Fujifilm X100F adds versatility, and I talked about how great the camera does at high-ISO photography, but I never talked about how these two things do together. I’ve noticed some things about using the Digital Teleconverter at high-ISOs that I’d like to discuss.

Does the Digital Teleconverter limit how high you can go on your ISO settings? The answer is simple: yes. But it’s actually a little bit more complicated than that, so let me dig a little deeper.

I’ve already discussed exactly what the Digital Teleconverter is, and I don’t want to spend much time rehashing that, but basically it’s a digital zoom (zoom-by-cropping) that receives some smart upscaling and sharpening to make the file appear to have more resolution than it actually does. It’s a software trick that allows you to print larger than you might otherwise be able to. You can do this yourself with software on your computer, or you can let the X100F do it for you (which is the Digital Teleconverter).

I’ve also discussed that the practical high-ISO limit on the Fujifilm X100F is 12800, which is very high. Yes, some cameras with larger sensors can go a stop or so higher, but ISO 12800 is way up there, much higher than I ever imagined ISOs going even just 10 years ago.

When using the 50mm Digital Teleconverter (16 megapixel crop) setting, ISO 12800 doesn’t look all that usable. If you want soft and grainy looking black-and-white images, you can get away with ISO 12800 using Acros and the 50mm option. I’ve produced acceptable results this way. However, for the most part, ISO 6400 seems like a more practical high-ISO limit for this situation.

When using the 75mm Digital Teleconverter (12 megapixel crop) setting, anything above ISO 6400 doesn’t look all that usable. ISO 6400 looks alright for soft and grainy looking black-and-white images using Acros. For the most part, ISO 3200 seems like a more practical high-ISO limit for the 75mm Digital Teleconverter.

You might have noticed a trend, and that’s a one stop loss for the 50mm option and a two stop loss for the 75mm option. It’s not that the camera is performing worse, it’s that you are looking much more closely at the exposure (because of the crop). You can more clearly see the degradation in image quality that happens at the higher ISOs. It’s kind of like pixel-peeping–you don’t notice certain things when viewing normally, but they become obvious when you zoom in.

If you use the Digital Teleconverter along with auto-ISO, pay careful attention to the ISO that the camera is selecting. You may need to set it yourself (very quickly and easily done via the knob on top of the camera). My recommendation is to go no higher than ISO 6400 with the 50mm setting and no more than ISO 3200 with the 75mm setting. You can get away with higher sometimes (especially if it’s only for web use), but for best results keep the ISO a little lower than you otherwise would.

Fujifilm X100F & High ISO


Bowling Shoes – Kaysville, UT – Fujifilm X100F @ ISO 12800

When it comes to high-ISO performance, digital camera technology has taken photography to a place that was impossible or nearly impossible not very many years ago. What used to be a fast film-speed is now just another ISO that looks like all the others.

I started photography in the age of film, and I studied film photography in college. It makes me sound old, but I remember when my high-ISO option was ISO 400 film! And if I was feeling daring, I might push-process that film to ISO 800 or (gasp!) ISO 1600 on a rare occasion. Only a couple of times did I dare try ISO 3200, and the results were super grainy.


Departures – SLC, UT – Fujifilm X100F @ ISO 12800

Nowadays ISO 400 seems closer to base-ISO than what most would consider high-ISO. Even ISO 1600 doesn’t seem all that high. Photographers routinely use ISO 3200 and higher. If you told me 20 years ago that this was going to be the case in the future, I probably wouldn’t have believed you.

All of this is truly amazing, and I wanted to lay out this context, because it’s easy to forget just how far this has come. Any camera that is capable of great results at ISO 1600 and higher is something that we should marvel at! And pretty much all cameras available today are capable of this.


Tabasco – Tooele, UT – Fujifilm X100F @ ISO 10000

The Fujifilm X100F, which has a 24-megapixel APS-C X-Trans III sensor, is capable of producing excellent high-ISO results well above ISO 1600. One reason for this is that there are more green sensor elements than a traditional Bayer sensor (55% vs. 50%). Luminosity information comes from green (while red and blue are for color information), so X-Trans cameras have a little more high-ISO headroom.

I have found that there is no practical discernible difference between ISO 200 (which is the base ISO) and ISO 800 on the X100F. There is a small increase in digital noise with each ISO stop increase above ISO 800; however, ISO 3200 is difficult to distinguish from ISO 800 (or ISO 200 for that matter) without a side-by-side comparison. ISO 6400 still appears great, but by this point the noise has become a little more obvious. ISO 12800 is a bit on the noisy side and noticeably softer, but it still looks good and I have no hesitation using it when I need to.


Sitting & Relaxing – South Weber, UT – Fujifilm X100F @ ISO 12800

Interestingly enough, ISO 12800 on the X100F reminds me a lot of ISO 1600 on my first DSLR from a decade ago. One of the biggest improvements in digital camera technology over the last ten years has been high-ISO performance.

There are cameras that go well beyond the ISO 12800 practical high-ISO limit of the X100F. But the high-ISO performance of this Fujifilm camera is truly amazing, all things considered. Ten years ago it would have seemed impractical and twenty years ago it would have seemed impossible. Yet here we are today, with good looking ISO 12800 right at our fingertips!


48 – Farmington, UT – Fujifilm X100F @ ISO 12800

I’m sure camera makers will continue to improve high-ISO performance throughout the coming years and decades. People will scoff that you could “only” get good results through ISO 12800 on the X100F. So what? You use what you have to the best of your ability and don’t worry about the rest. Do you think it really matters in the long run if you can’t shoot at ISO 25600 or ISO 51200? I’m personally happy to get good results above ISO 400, which wasn’t always an easy task in the days of film photography.

The photographs in this article were captured using the Fujifilm X100F. All are out-of-camera JPEGs using Acros or Classic Chrome. The camera can add faux film grain (Acros does this automatically, while Classic Chrome is either toggled on or off), and all of these have grain in additional to the digital noise.


The Tortilla Maker – Layton, UT – Fujifilm X100F @ ISO 12800