ISO 1600 vs correcting exposure in photoshop

[Daniel Browning]

Gabor is very deep like you Daniel.

Thanks. That's one of the things I really like about him. (There are some personality quirks of his that aren't as enjoyable, but no amount of faults will make up for the great service he did in building Rawnalyze.)

I'm not seeing the headroom in post that Sheehy shows in his 5D MkII graph for the 40D or 5D.

His chart is just for the green channel. As you know, most light is unbalanced (tungsten, sunset, etc.) so that can make a big difference. It could also be just the way your raw converter is showing things to you. You can eliminate that factor by opening the file in Rawnalyze. That will show you *exactly* where all the values are. (For example, you can drag a square around a card that is supposed to be middle gray, and it will tell you how many stops from *true* clipping it is, such as "-3.5".)

The 40D tweenies are the same as the 30D so if the new 5D MII is configured the same way 160,320,640 etc. would be the tweenies I'd be shooting with.

Yep. They are the same way.

Question: Has anyone done a dark noise histogram plot of the 5D MkII like the one done here?

I did for ISO 1600 and 3200 when I first got it in December, but I can't find them now. I'm sure there are some on the web somewhere. Remind me next week and I'll spend a little time shooting some blackframes. (I was trying to decide if the read noise improvements in ISO 3200 would be enough to sacrifice 1 stop of highlight headroom -- they weren't.)