I was recently discussing photography with a friend who wanted to get more out of his newly purchased Nikon D50. After explaining the 3 basic drivers for exposure- aperture, shutter speed, and ISO- he asked why, since ISO is a crossover element from film-based photography, we continued to need that. A good question, I thought. I couldn’t put into words why but, I knew even in the new digital age it would remain an essential piece of the exposure puzzle.

This question steeped in the back of mind the last few weeks until I was reviewing (i.e. dreaming of someday getting) the Nikon D3. For those that don’t know, it has low noise ISO up to 6400! And by low noise, I mean like Barry White-low!And, it can expand its ISO range to 25,600 with just a little noise!!! If you consider that most of the current pro-sumer DSLRs out there have an effective ISO range of 200-1600 (give or take), that means D3 users get TWICE as many ISO stops as most of the rest of us do! That’s not just ‘a nice bonus’, I believe this is the beginning of what will be a paradigm shift in how we think about, and approach, exposure.

When I pick up my camera for a shoot, unless the conditions call for a change, my ISO is set right around 400. And, unless I’m feeling artsy, I’m shooting in Aperture Priority mode. When I really think about it, that’s pretty limiting. How often do I want a precise DoF (aperture) AND shutter speed at the same time, but I don’t have the latitude in ISO to accomplish it? Not to mention that even if I did have the latitude, I’d have to fumble through the camera menu to change it. What if there were such a thing as Aperture/Shutter Priority, where I could set them both and the ISO adjusted appropriately? I think we are seeing the beginnings of that.*

Some day soon we’ll have M, A, S, P, and A/S modes, and probably other combinations thereof, as well. Sensor technology will continue to improve, hopefully adding a few stops every 5 years. At that rate, it will just be 10-15 years before we’ll have the same range of stops available to us in aperture or ISO priority mode (assuming Moore’s Law doesn’t speed up that evolution even faster)… just think of the possibilities!

I’m still trying to flesh out the ramifications of a 50% increase in exposure parameters that are fully flexible…

When you consider these ISO advances along with the advances being made in the dynamic range of sensors, the potential convergences ahead of us get pretty exciting, pretty quickly!

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*I first put this whole ‘Future of ISO’ idea into writing as a discussion thread in a private Flickr group.

One respondent mentioned that “Most high end cameras have AutoISO…”, to which I responded:

“I wasn’t aware of that… well, that’s the first step, isn’t it? Now it’s just going to take all of us continually thinking about ISO in terms of an equally adjustable element of the exposure. And, AutoISO, I would imagine, is a setting reached via the menu? To put my concept into camera terms, this “shift” (in thinking) would involve moving that from a menu setting to a mode on the exposure dial.”

Another said: “You’ll notice that on all the non-automatic modes, the consistent thing that you can adjust throughout is the ISO. For film SLRs, typically the fastest film you could buy was 800 ISO. ISO no longer has the same meaning it did with film.”

My response: “Agreed. But what I’m suggesting is that we haven’t fully adopted the ISO as an adjustable parameter on par with aperture and shutter speed. Sure, we think about it, but I would argue not nearly as often as the other two.”

Anyway, this was just a random thought and I’m sure it will evolve over time… I’ll be sure to comment back here with updates!