[Leica] Re: the dynamic range of digital

[schneiderpix at mac.com (Robert Schneider)]

Here's where I think panties are getting in a bunch.  George's  
testing idea is correct IF a few elements are sorted out.  First one  
needs to know the correct ISO to expose for.  Many digicams,  
professional and point & shoot, do not expose at their rated ISOs.  A  
camera set at ISO 100 actually may be recording, for instance, at ISO  
80 or ISO 160.  Fortunately with digital it's  quick to determine.   
The bigger issue is making sure to evaluate the resulting histograms  
in your RAW converter, not on the camera's LCD screen.  As all of the  
previously cited articles state, the LCD histogram is adjusted to  
display the JPEG histogram in your working color space, with a  
contrast curve applied, regardless of whether you're shooting RAW or  
not.  The linear RAW histogram would be all bunched at the low end  
and the screen image would look nearly black.  Where the camera  
histogram is showing saturation at 255 and flashing (blown)  
highlights, the RAW reality may be different -- from 1/3 to a full  
stop different depending on the situation, the camera, etc.

I have never seen a DMR on the hoof.  Based on Doug Herr's  
observations, it is conceivable to me that Leica has employed a JPEG  
algorithm that leans toward slight overexposure.  Thus, to keep from  
looking at blinking highlights, it's necessary to use negative  
exposure compensation.  But if the histogram IN THE RAW CONVERTER  
program shows data in the right-hand fifth, then we're all saying the  
same thing.  If anyone is looking at RAW converter histograms that  
consistently lack data in the right-hand fifth, then they are  
underexposing their images and omitting up to 50 percent of the  
potential capture data.

Unless I'm missing something basic, that's the way silicon capture  
devices work, whether made by Kodak, Panasonic, Canon, or the  
wandering ghost of Oskar Barnack.

On that, I'll let this one go.  Doug Herr and B. D. apparently have  
issues with each other with a dynamic range far exceeding the chips  
in either of their cameras.  Though it is completely accurate to note  
that from the E500 to the E-1, Doug's IS bigger than B. D.'s.

Rob


or George Lottermoser wrote:

In reality: I believe that we're all saying the same thing; achieving
the results we're pleased with; with the equipment we've chosen;
given our economic condition and goals. As I said in my last post run
the test with your equipment, use 2 degree spot meter and you can
place values exactly where you want them each and every time.
However, in the field, with in camera metering (matrix or otherwise),
and quickly changing conditions, one cannot always use the zone
system. Most of the conflict in this discussion seems more about
personal chemistry than photographic science. ; ^ )

Regards,
George Lottermoser
george@imagist.com