ISOless sensors, read noise and photography - many questions!

Started Oct 3, 2013 | Discussions thread
RussellInCincinnati Veteran Member • Posts: 3,201
of course we should always include examples

RussellInCincinnati wrote: To recap, in the field when you need a photo above ISO 800, set the camera to an ISO at least 1 and perhaps 2 stops lower than what you think is indicated. Viewfinder will still be usable, and you can fix the ISO in raw post-processing.

WilbaW wrote: Make sure you try this idea before you buy it.

Well am going to restate your comment a tad more diplomatically as "Russell could you show us an example of easily pushing an ISO 800 raw file to ISO 4000, as you so conveniently did in one of your other threads ? " And the answer is, of course why not, when nowadays examples are so easy to post?

A few years ago I did that experiment and found that it was possible to "fix" such a shot using esoteric software and elaborate methods,

Which happily, in 2013 has come down to 15 seconds or so of work in Lightroom 4.x or higher.

...involving sliding the "highlights" control all the way to the left, the "shadows" control all the way to the right, and finally sliding the exposure control to the right as many "stops" as needed to compensate for your too-low-in-camera-ISO-setting. As shown above.

In more detail: You're raising the "shadows" control to make the dark areas as bright as possible. You're raising the "exposure" control to "push" the ISO back to about 4000 or so, since the raw file was exposed at a "too low" ISO 800. And finally you're lowering the "highlights" control because if you didn't, then raising the exposure control would send the brightest parts of the original image through the roof. Just finished a job shown above, involving delivering 125 images the day after they were taken, and almost every "underexposed" ISO 800 image involved reusing just the 3 settings described here. Most of the batch was with exposure set to +1.5 EV or so (maybe ISO 2000 in camera woulda been about right), the above example needed +2.33 EV ISO push in Lightroom.

and while the noise was equivalent the colour in the shadows was never quite as good as the shot with the ISO that gave normal/desirable image brightness. In my case there was no pay-off to justify doing more work to get an inferior result.

Yes, your story reminds me of my own experiments with low ISO done in 2010 with a typical photo editor. Like you, after a bit of playing around with dark raw files, I gave up on the idea of using too-low-ISO in camera until a few weeks ago. When Boardsy started this thread, showing his own great results pushing a "too low ISO" image.

You WilbaW probably did what I did 3 years ago, starting with a low-ISO image like this

...and then you put it in a typical photo editor and slid over a "brightness" control to some high value. And you ended up, as I did, with something like the "brightened" sample below, that convinced you at the time that it was best to leave high-ISO signal amplification to your camera's firmware:

But it's time to re-check the ability of an ordinary $80 dollar raw file processor such as Lightroom 4 or better to make it easier, and less stressful and really better to raise your raw file's ISO in post-processing than in-camera:

Please feel free to check on the ease of getting a great result (well the above batch of work resulted in me being hired immediately as staff event photographer) from a "pushed to ISO 4000" Nex C3 ISO 800 raw file yourself, by downloading the above .ARW file into Lightroom 4, 5, free RawTherapee, whatever:

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