Owners: ISO reports, please.

[PaPa]

yes it is. But my question was more the curiosity as to whether or not lowering the contrast in Neutral would yield the same result as doing a custom profile and lowering the contrast. I would assume yes, as these are just quick presets.

 

[marco0782]

I find that ISO 800 to 1250 can yield a clean image if you are exposed properly and the frame contains a reasonable amount of highlights. When you underexpose the higher ISO's, that's when things get bad.

Also, I have shot 640 ISO and lifted by one stop in post (Magic Bullet) and the image remained clean. I achieved a better result doing that than shooting 1250 ISO.


Marco

 

[USLatin]

I've been getting tons of good info out of Daniel Browning on this REDuser thread: http://www.reduser.net/forum/showthread.php?t=34434&page=27

He is knows so much about digital acquisition he puts my head into a spin when he gets going on a rant.

The following seems very useful if you are trying to squeeze every little bit of quality and dynamic range out of the camera with controlled lighting.

If you adjust ISO, but keep brightness the same by changing exposure, then the dynamic range is highest at ISO 100, stays about the same at 200, then starts going down from there. The dynamic range will vary most greatly by the picture profile settings. With low contrast settings, ISO 200 will have more dynamic range than ISO 400. But with high contrast, the difference may not be noticeable.

The "plus 1/3" ISO settings (125, 250, 500, 1000) should be avoided, as explained above. The "minus 1/3" ISO settings are fine, as long as you know that they have 1/3 less highlight headroom.

Highlight tone priority trades one stop of shadow noise for one stop of highlight headroom. I use it a lot. It should always be enabled for ISO 3200 and 6400, since in those cases there is no noise penalty from HTP, so you get the one stop of highlight headroom for free.

The "acceptable level of noise" varies by exposure, light, settings, and personal taste. A high key shot at ISO 1600 can look like ISO 100 because it has so little noise. Shooting in the perfect magenta light can make ISO 6400 look like ISO 800.

Here's a start. Assuming a floating exposure:

• 100, 200, 400, 800, 1600: normal amount of highlight headroom.
• There is little difference from ISO 100 to 200, because most viewers can't tell the difference in photon shot noise, and the read noise drops by almost a full stop in ISO 200.
• 125, 250, 500, 1000: considered harmful. 1/3 stop less highlight headroom and 1/3 stop more shadow noise.
• 160, 320, 640, 1250: fine, as long as you are aware of the decreased highlight headroom. (Clips 1/3 highlights to get 1/3 more shadows.)
• HTP should *always* be enabled when the ISO is higher than 1600.
• There is a careful balance between increasing shadow detail through ISO (which clips highlights) or through HTP, the picture profile (e.g. contrast, tone curve), or Auto Lighting Optimizer. Generally, the higher you go in ISO, the more beneficial it is to use non-ISO methods to increase shadow detail. For example, ISO 3200+HTP (actually ISO 1600) is better than the real ISO 3200. ISO 800+HTP may be better than the real ISO 800, but it depends on how much highlight headroom you need.

Hope that helps.