Why 'more or less stopped using ISO'?

Started Feb 19, 2014 | Questions thread
The_Suede Contributing Member • Posts: 651
More or less "practical" response...

l_d_allan wrote:

In a recent thread where the OP was about base ISO
What determines a sensors Base ISO?

I was unclear about the following posts ...

bobn2 wrote:

Iliah Borg wrote:

Bob, even with film ISO rating is not very useful, it is just some approximate guideline. It is even less useful with digital. You know that...

I do know that, Iliah. Personally, I've more or less stopped using ISO.

I'm in the category of "not knowing that" ... about digital ISO being less than not very useful. Please clarify.

  • Is this specifically about "iso-less sensors" like many Sony and Nikon cameras?
  • So for such cameras ... just leave ISO at the camera's base ISO (typically 100)?
  • ...
  • Or does this also applies to Canon DSLR's (which I don't think can be described as iso-less)
  • Or because modern DSLR's have so little noise that use of Auto-ISO is appropriate?
  • So bobn2 and Iliah aren't concerned about what ISO is picked by Auto-ISO?

I can't say that I "stopped using ISO" in a real, assignment-centered case.

What I've done is to change my priorities by quite a noticeable margin...

There are several usage scenarios where I no longer fret about whether I've "nailed exposure" or not with my Nikon or Sony cameras. In short, those scenarios can be delimited by:

  • The scene is an "ISO400+" scenario, where shutter speed is the main concern.
  • The scene is a base ISO scene, that contains little or no really image-important information close to black

In the first case, I often do that by setting Auto-ISO and -1Ev or even -2Ev in exposure compensation. Especially in theatre or music scene scenarios, -2Ev saves a lot of ugly discoloration in blown highlights (spotlights are often colored...). On Canon cameras, this is also quite applicable after ISO640 - there's no real loss induced.

In the second case, I set -0.33 to -1Ev and just let the result be what it becomes - I might not be "noise optimized" with regards to read noise (electronic noise) in the camera - but on the other hand I'm saving quite a lot of point highlights with very little practical concerns for image noise. This is where Canon and older Samsung cameras fail to be as flexible as cameras with better low-ISO DR.


When the scene is static and I shoot at low ISO, like in studio or landscape/cityscape scenarios, I usually push the exposure right up to the edge of something blowing. This is since I can then know that it won't hurt the image, the scene won't change quiclky and surprise me (into blowing stuff inintentionally) - and it will at least theoretically have a very slight, but not non-existent image quality impact.

So, I haven't "stopped" using ISO. I just use the camera ISO setting in a much more flexible way - often with a very good and often even image quality improving end outcome.

Flexibility means better error margins. The downside is that you can't just let everything slide as if you don't care. You still have to be in your "best margins" region, and that is still totally in the responsibility of the user - me. And it's oh so easy to get sloppy when you know you have good safety margins...

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