Expanded ISO Settings: Why I Don’t like’em

by | Feb 11, 2021

Today’s Post by Joe Farace

Some of the following text originally appeared in a print edition of Shutterbug for a review I wrote about a Nikon DSLR. Since people are always asking me my feelings about “expanded” ISO settings and why I don’t like them, I’ve excerpted some material from it along with some new, car related photographs, that explain why.

Although the DX-sized image sensor found in cameras like the Nikon DSLR that I tested, eschews the full frame of its more expensive siblings, the image quality this format—please don’t call it a “crop” sensor—pumps out has me rethinking the whole idea that “I gotta have a full frame.”

Sure there’s that whole 1.5X lens multiplication factor that comes along with a smaller sensor but I found that most new APS-C sensor DSLRs deliver extraordinary image quality along with relatively low noise throughout their ISO range.

As DSLRs and mirrorless cameras get better and better, they are offering higher and higher ISO settings. The Pentax K-1 Mark II has a high, not extended, ISO of 819,200. That’s not a typo. (You can see some images of that and read my review of this camera here. Spoiler: that high ISO is not so great.)

A DSLR, like Nikon’s D7200, has a standard ISO range of 200 to 25,600. If you choose the Lo-1 option, that low number changes to 100 just as when using the Hi-1 setting it increases to 102,400. And before I’ll get e-mails claiming that some DSLR have a lower (than native) ISO of 200 and a high that’s higher than native, let me share me what a Nikon engineer told me about using these expanded modes.

The engineer told me, “Our engineers carefully study and design sensors and associated circuitry to minimize the effects of noise that is introduced with each increase in ISO setting. The expanded settings are just that, expanded beyond the range that is considered optimal or acceptable by our camera designers and engineers. These settings are labeled differently to indicate that these are for emergency purposes (italics mine) and clearly identify where noise and color distortion will affect picture quality.” He goes on to say that “application of in-camera (and post-production) noise reduction can mitigate some of this noise but some will inevitably still remain at the very highest ‘expanded’ settings.”

How I made this shot: The image was slightly cropped and shot with an APS-C sensor Canon EOS 7D with EF-S18-135mm f/3.5-5.6 IS lens (at 18mm) and an exposure compensation of +0.33 stops. Exposure was 1/5 sec at f/3.5 and ISO 1250 but even at that relatively modest ISO there is some fine grain noise from the RAW file. The image was color corrected using iCorrect Portrait from PictoColor to minimize color pollution from the daylight coming through the blue colored roof. I know it’s not a portrait but the useful plug-in works for all kinds of subjects.

And now you know the rest of the story…

If you enjoyed today’s blog post and would like to treat Joe to a cup of Earl Grey tea ($2.50), click here.

Along with photographer Barry Staver, Joe is co-author of Better Available Light Digital Photograph that’s available from Amazon for $21.77 with used copies starting around four bucks. For some reason, the Kindle price is really high, not Barry or myself.