Archived posting to the Leica Users Group, 2006/09/20

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Subject: [Leica] Re: the dynamic range of digital
From: bd at (B. D. Colen)
Date: Wed Sep 20 05:48:12 2006

Hoppy - Unlike some, I claim neither to be an expert, nor an instant expert
on the technical side of digital. But I find a great deal of what's on
Luminous Landscape to be both helpful and accurate. That said, what the
article says is that in order to extract all the useable information from an
image, one needs to expose in such a way that the histogram is shoved right
up to the far right side of the scale, without going over; anything that's
over the edge is lost. What the article also says is that the further one
moves toward that right side, the higher the proportion of useable data, and
underexposing by a stop - or shifting one stop away from the right edge -
throws away - fails to capture - at least 20 percent of useable data. Now as
Don notes, in the 'real world,' it of course comes down to the accuracy of
one's meter and one's preferences. It is of course possible that Doug's DMR
metering has a built-in one stop over bias, and that to get accurate
readings he needs to shift dial in a stop under. On the other hand, I assume
Doug is also taking incident readings on occasion, and I also find it
extremely hard to believe that the DMR's metering system isn't the most
accurate ever built in to any camera, film or digital.

On 9/20/06 12:03 AM, "G Hopkinson" <> wrote:

> B.D. I'm not trying to muscle in here, and I've never used a DSLR. I really
> want to understand better. I don't follow your
> reasoning, here. I'd read that article before and reread it on your post. 
> It
> seems to me that it supports what Doug is saying. By
> slightly underexposing, are you not helping to preserve detail in that 
> first
> lightest stop which has the most information? Then you
> can adjust the tonal range later but you must preserve the detail in those
> highlights, those that aren't specular? Isn't Doug's
> approach going to preserve more tones in the highlights and potentially 
> lose
> less in the shadows? That is lose much less information
> because of the linear performance of the sensors. Now just how much of that
> information you can actually reproduce in a print,
> either near pure white or black is a different issue. As a practical matter
> your system obviously works for you and Doug's for his
> subjects. There are clearly other factors at work.
> I'm looking forward to learning more.
> Cheers
> Hoppy
> -----Original Message-----
> From:
> [] On Behalf Of
> B. D. Colen
> Sent: Wednesday, 20 September 2006 12:58
> To: Leica Users Group
> Subject: Re: [Leica] Re: the dynamic range of digital
> Being the digital expert you are, Doug, I would have thought that you'd 
> know
> that by under exposing a stop, you're throwing away everything at the top
> end of the range - in the highlights - not the shadows - and 20% of the 
> data
> is in that top stop. But I don't use a DMR, so of course I know nothing
> about digital ;-) - so don't listen to me, but do try reading this...from
> the Luminous Landscape site....
>> In my experience with the DMR, setting exposure comp to -.5 or -1
>> sacrifices very little deep shadow detail if any.  It's not what I'd
>> call a 20% loss of data.  The histogram (yes it's RGB) is nowhere near
>> clipping at either end aside from specular highlights.  Perhaps B.D.'s
>> 20% estimate is based on his experience with the E-1?
>> Doug Herr
>> Birdman of Sacramento
>> _______________________________________________
>> Leica Users Group.
>> See for more information
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> Leica Users Group.
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Replies: Reply from hoppyman at (G Hopkinson) ([Leica] Re: the dynamic range of digital)
In reply to: Message from hoppyman at (G Hopkinson) ([Leica] Re: the dynamic range of digital)