Hi all,

I was watching a video by TNG (http://www.youtube.com/watch?v=MA_8U...&feature=g-u-u) where he discusses ISO in detail. Specifically, he talks about the dynamic and tonal ranges for example on the D4 are widest at around ISO 75 despite base ISO being 100.

He also suggested in a comment the only disadvantage to using an ISO below base is the affect on shutter speed. I've done some research and apparently others believe ISO 50 for example is created artificially (apparently the same as ISO 100 +1 compensation, then artificially reduced) which reduces the ability to recover blown highlights in PP.

Eh I'm not following to be honest. DxO Mark (http://www.dxomark.com/index.php/Pub...or-performance) seems to suggest for the D800 the best dyanmic range, SNR and colour depth is around ISO 75. So, should I where ample light is available use ISO 75 rather than ISO 100 (base)? What's the disadvantage in doing this besides the affect on shutter speed?

Cheers