Dpreview's OM-D E-M5 Review, Second thread

Started Apr 30, 2012 | Discussions thread
Richard Butler
dpreview AdminPosts: 1,929
Re: Question on Auto Gradation
In reply to assaft, May 1, 2012

assaft wrote:

A related question I have is whether you noticed a significant difference between (a) - applying Auto gradation at exposure time; and (b) - applying Normal gradation at exposure time and then changing the setting to Auto in the development of a raw file using the Oly Viewer 2 developer. I know that option (a) sets a higher shutter speed in order to protect the highlights, so as far as I understand, this option has more lifting work to do and probably introduces more noise. But regarding DR - does the tonal range scale you published for the Auto setting on page 18 is approximately the same for both option (a) and option (b)?


The difference between (a) and (b) is that you'll get more highlight detail in (a) than (b), but also more shadow noise. This should only happen if the camera detects high contrast in the scene (Grad Auto is relatively clever about whether it uses a different shutter speed). I've not shot the two back-to-back, so I don't know how significant that difference is (I'll have a go later).

The example shot given, at ISO 800, was exposed with Grad Normal and then re-converted in-camera so, as you say, the shadows might not have been pushed as much as if it were natively shot with Grad Auto (depending on what exposure it chose).

The tonal range seen on page 18 is based on allowing the camera to change the shutter speed - that's where the extra highlight range comes from. The fact that the tail of the curve goes on further than for Grad Normal suggests noise isn't excessive, but I'll look into it.

Richard - dpreview.com

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