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Re: [OM] Olympus Viewer, ACR, highlights, distortion and vignetting [was

Subject: Re: [OM] Olympus Viewer, ACR, highlights, distortion and vignetting [was Arrrrgggghhhh. Need sleep.... need sleep.....],
From: Ken Norton <ken@xxxxxxxxxxx>
Date: Wed, 6 Mar 2013 16:55:22 -0600
Using a target (IT-8?) for controlled testing was quite the eye-opener
for me. In the digital world, I believe that the class leader in
highlight recovery has been the original 5D, but I'm pretty sure that
the new D800 is giving it a good run for the money from what I've been
able to extrapolate from people's images.

The E-1 is a pain when it comes to highlights. There. I said it. The
E-1 has a fault. Sue me.

The cause of the problem is not apparent without doing testing with a
calibrated target. Highlight recovery does not work the same on an E-1
file as it does with most "normal" digital cameras. It has to do with
the way the four color sensels are combined. Anything within 1/2 stop
of clipping will start to color shift AND clip. When you do a
highlight recovery, you'll get substantial color shifts. ETTR is fine
as long as you give yourself a little bit of fudge room at the right
side to allow for the sensel merge to work things out.

The name escapes me as I'm not anywhere near my editing computers,
(rawdigger?) but I have a program that gives me the ability to pull
histograms on all four color channels of the E-1 sensor. II'll have to
show pictures for you all of images that are at or near ETTR and what
happens when the RAW file is processed. It's bad soup that will give
you cramps for sure.

Historically, I've gotten my best images when I have a full stop of
headroom. I have multiple RAW converters with highlight recovery and
with many images that works very well. But on other images, there is
no saving it as the colors wonk out. Portraits, especially, seem to
benefit most when I pull the exposure up rather than down.

-- 
Ken Norton
ken@xxxxxxxxxxx
http://www.zone-10.com
-- 
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