Archived posting to the Leica Users Group, 2008/05/17

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Subject: [Leica] IMG: Yosemite too... and Raw exposure for dynamic range
From: hoppyman at bigpond.net.au (Geoff Hopkinson)
Date: Sat May 17 18:59:09 2008
References: <200805120220.m4C2KAgp083462@server1.waverley.reid.org> <BLU121-DS3D167B73DE9448543EE95D4CC0@phx.gbl>

Hi Aram, I have been enjoying the Yosemite work from you guys. I'll be
visiting in December. I loved your dead tree as well and credit to you for
showing some textures and alternates as well as the absolutely obligatory
spectacular scenery. 
I looked carefully at your HDR example of the falls. You guys haven't
convinced me yet on HDR. (I haven't tried it for myself). I get that the
principle is that you are trying to increase the recorded dynamic range by
combining exposures and I can see that the falls shots is a very contrasty
scene. Bu the highlights (water) and blacks are still clipped here (as
shown). I don't know which Raw converters you use but I am having success
with the latest ACR bringing back clipped highlights. Try this and let me
know what you think:
Make your exposure for the highlights without any -EV in camera. Ideally as
close to clipped as you can. Keep in mind that the camera histogram is from
the jpg preview, not accurate for the Raw information.
Open in converter and adjust the exposure until you have a full range to
255. Try recovering as needed, one or more channels may not be clipped. ACR
does better there. I think. Excepting for tiny specular highlights, you want
the lightest possible exposure with the highlights JUST below the clipping
warning IN RAW. This way you have the maximum number of original linear
tones in the highlights before the gamma curve to approximate our
perception. Yes I know that we don't differentiate those brightest values
very well. The object is to start with the maximum number of linear tones in
the range. Then when the gamma adjustment is made, as the tones are
repositioned you end up with the range pushed downward, hence the maximum
possible number to differentiate the mid-tones and increases in those vital
shadows. That equals more range (and less noise) in that shadow end. We
already know that the M8 is a superb tool for rendering those darks.

Example ACR processing. See histogram for tonal range.
Default exposure for centre bright area and contrast. 
<http://www.pbase.com/image/97208285>
http://tinyurl.com/6r9vt2



Cheers
Geoff
http://www.pbase.com/hoppyman/e
http://gallery.leica-users.org/v/gh/

-----Original Message-----
From: lug-bounces+hoppyman=bigpond.net.au@leica-users.org
[mailto:lug-bounces+hoppyman=bigpond.net.au@leica-users.org] On Behalf Of
Aram Langhans
Sent: Monday, 12 May 2008 13:25
To: lug@leica-users.org
Subject: [Leica] IMG: Yosemite too...

Bob.  Liked your photos.  I just got back from Yosemite, too.  We were there
from April 28 To May 2.  Wasn't the weather just great?  Here are a few
shots of Yosemite falls I took.

http://gallery.leica-users.org/v/Aram/Yosspr08/Yosemite-falls_HDR2.jpg.html

http://gallery.leica-users.org/v/Aram/Yosspr08/yosemite-falls-4204-Edit.jpg.
html  Just love that dead tree.

http://gallery.leica-users.org/v/Aram/Yosspr08/yosemite_falls-4201.jpg.html

http://gallery.leica-users.org/v/Aram/Yosspr08/yosemite_falls-4194.jpg.html

The first one was using the HDR of Photoshop.

I'll be posting more later.  Just got back 3 days ago from a long return
home.

Comments and criticism welcome.

Aram 

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Replies: Reply from kcarney1 at cox.net (Ken Carney) ([Leica] IMG: Yosemite too... and Raw exposure for dynamic range)
Reply from pdzwig at summaventures.com (Peter Dzwig) ([Leica] IMG: Yosemite too... and Raw exposure for dynamic range)
In reply to: Message from leicar at q.com (Aram Langhans) ([Leica] IMG: Yosemite too...)