The penalty of raising ISO
We talk a lot about the great ISO performance of the D800, but its easy to ignore the tradeoffs.
The D800 is particularly good at not creating noise in the shadows when you raise ISO. I'm pretty comfortable at ISO 800-1600, and readily go beyond that level.
But as we increase ISO, we lose dynamic range. Based on Bill Claff's data, for every stop ISO is increased, we lose nearly 0.75 stops of dynamic range. So in essence, the EV is largely fixed based on shutter and aperture selection, and increasing ISO is simply adding amplification for all exposure values.
I find we are a bit too free to increase ISO at the expense of dynamic range.
This has some practical application. With a D800, if a scene has a difference of 8 stops between the brightest and darkest areas, we need to keep ISO at 1200 or lower to have 8 stops of dynamic range. Above ISO 1200, the dynamic range of the scene exceeds our ability to record the image. The results are about the same for a D4.
With a D7000, you would need to shoot at ISO 500 or lower to capture the 8 stops of dynamic range.
You might use spot metering to estimate the difference between brightest and darkest areas of a scene, but that probably will take some practice as most of the time bright and dark areas have some variation.
This suggests that expose to the right is a good strategy at base ISO, but less so if you have to increase ISO since it decreases dynamic range.
By the way - has anyone heard from Bill Claff? I sent him an email recently because he has not been active here. I got no response.
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#1. "RE: The penalty of raising ISO" | In response to Reply # 0
#2. "RE: The penalty of raising ISO" | In response to Reply # 1
#4. "RE: The penalty of raising ISO" | In response to Reply # 0
Eric, I had never seen this data before! If Bill Claff collected this data, he did a wonderful job. WRT the D800, I looked at a number of different models and couldn't find anything that exceeded the DR of the D800 at any particular ISO (which made me happy), and even my OM-D E-M5 was listed (quite a surprise) with fairly good results for a "miniature" camera!
So Thanks for posting this thread, and thanks to Bill for creating the chart (amazing interactivity by the way).
D810, D750, N1-J5, N1-V3 (and a few other cameras) and a BIG handful of lenses.
#5. "RE: The penalty of raising ISO" | In response to Reply # 4KnightPhoto Nikonian since 18th Dec 2006Sun 12-Jan-14 12:47 AM
Bill has been a great long-time contributor here at Nikonians and glad to hear he is fine and busy!
Huge contributor to many peoples understanding of ISO and Dynamic Range,
Best regards, SteveK
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