What Is the Highest Usable ISO?

ISO and digital noise are often a cause for concern with photographers. In this video, I look at how much noise is acceptable in an image and how that varies depending on the application of the photograph. 

Many moons ago, photographers lusted after the most beautiful grain they could find in a film emulsion, shooting delta 3200 for its soft grain, developing film in Rodinal for really high acutance, and a one-degree Celsius increase in temperature to make the grain the size of a golf ball. Then along came digital. For many years, the digital cameras couldn't really go above ISO 400 for 35mm cameras and ISO 100 for medium format. Since then, a lot has changed, and the ISO that can be reached by a camera means that you can photograph pretty much anything anywhere. However, with high ISO comes more than noise, as I discuss in this video.

There is a plethora of noise reduction software out there, although I have personally never found a need for it. Understanding your sensor and the scene can do far more than putting a raw file through a processor. Nevertheless, there are certainly times at which an ISO is as high as it should be and that going further may be detrimental to the application of the image. In this video, I look in detail at various ISO settings from a scene in my studio and discuss where each application would be appropriate to be used. 

What are your views on ISO?

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18 Comments

I shoot as low iso as possible. I am thankful to shoot with a Nikon D5 which is amazing in low light. I shoot a ton for a major aquarium chain and their low lighting in their tanks requires i shoot above 10,000 iso. There is noise, but it is manageable in ACR. The results are amazing given this was impossible one camera ago.

I photograph a lot of Lurcher racing for my local club. The dogs are running towards me at speeds in excess of 40mph at distances of just a few yards.
I use the long end of a 70-200/2.8, wide open and my D850 is set on Auto-ISO to prevent the shutter speed dropping below 1/2500 second.
The high ISO performance is such that I no longer worry what ISO the camera is going to select.
For walkabout use, the camera is set to ISO 64 unless light levels are low enough to require a higher setting.

Farhaan Tariq's picture

ISO is FAKE.... here how tony northrup proves it! https://www.youtube.com/watch?v=2jkf31w7fwU&t=4s

Stuart Carver's picture

Lol Tony Northrop, give it a rest

Walter Kovacs's picture

It's almost as though he is completely unfamiliar with first principles.

What a joke. That person does not understand ISO at all. ISO is all about the gain of the sensor. The higher the gain, the noisier the image. It is all about the poisson-distribution of photons and the distribution of data over the histogram.
I read of this person sometimes here in FS or he posts comments here himself. Most of the comments do not represent facts but only his narrow and apparently uneducated view or it seems he just simply makes things up. Not much of an expert, I'd say.

Well yes and no. While photons are one part of the equation, read noise is another. How the amplifiers are designed, implemented, and how thermal constraints are managed should not be overlooked. Additionally, continuous improvement in NR algorithms further mitigate the effects of noise. Once again Tony heads south on his analysis.

While you are correct, the read noise of modern(!) sensors and the noise of the amplification can be neglected at base ISO. At higher ISOs, the signal level is dominated by shot noise. Thermal constraints could be a problem. But this affects video much more than photography.
Edit:
Source: https://www.researchgate.net/publication/301273217_Reduction_of_CMOS_Ima...
and
https://www.adimec.com/dynamic-range-dnr-and-signal-to-noise-ratio-snr-f...

Stuart Carver's picture

As high as is needed to get the shot with the equipment you have at hand?

Spy Black's picture

Whatever ISO you need to get the shot is the ISO you use. It's doesn't matter how noisy your image is, you either get the shot, or you don't.

ted partrick's picture

My biggest concern with going too high with iso is limiting my crop range. If I can compose my shot well, I don't worry. Very helpful video; thanks.

Larry McNiff's picture

After watching Tony and Ken's videos in this thread I think I get it. Don't toss a piano off of a tall building because it will cause a lot of noise when it lands! In that case, ISO doesn't cause more noise.
One thing Tony forgot in his longer shutter speed suggestion is that thermal noise will start building up over longer shutter durations. This was an issue with sensors used in astronomy/astrophotography. The sensors had to be cooled to reduce thermal energy buildup (increased sensor noise) during longer exposures. Taking Tony's additional advice, they should have added a couple soft boxes for those astronomy photos and kept the ISO low! (lol)

"In theory, theory and practice are the same. In practice, they are not!" - A. Einstein

Tom Weishaar's picture

great advice re the piano... can't stop laughing. Also love the Einstein quote.

Graham Glover's picture

"What are your views on ISO?"

They've just changed with your video. I am an amateur and while I print, almost everything I shoot is for online viewing. I have no issue shooting very high ISO, as some of what I shoot is sports and some of what I shoot is in very low light situations where shooting hand-held is the only option.

My view just changed with regard to noise reduction. Whereas I have used noise reduction to the extent that it doesn't seem to significantly affect the image, I just looked at one of my favorite images shot at high ISO in very low light. I'd struggled with noise reduction, knowing I could only go so far with it before the quality went bad. I just zeroed it . Yes it's noisy, but it looks better.

Will I stop using noise reduction? It's now an option.

Thank you!

Benoit Pigeon's picture

I don't like all the clipping in higher iso especially when it comes to colors. I often shoot fast race cars at night which requires a lot of extremes regarding set ups. I don't go high in iso and prefer to fill with strobes or at least a fill. I know quite a few people who don't want to bother with the complications I set my self into and push to some very high ISO instead. To me, if it can't print, I have no interest in my image. I care about the whole result and have no interest in deliberately ignoring parts of the photographic result. That's just me.

The B&W reminds me of all my work in the 70's.
I learned that good lighting makes the difference in IQ once I started using flash in the late 70's and saw a huge improvement in color, contrast and sharpness.

Today I use lighting in almost every situation except those where flash is not allowed or practical.

is that a Godox softbox on a Broncolor Pulso head? quite an unexpected mix :D