Digital BW, The Print

In a message dated 7/9/2005 2:04:11 P.M. Eastern Daylight Time,  
DigitalBlackandWhiteThePrint@yahoogroups.com writes:

Now  maybe someone will 
concentrate on the sensitivity and dynamic range of the  sensor and 
associated electronics.

Truman
I don't think dynamic range compression has ever been an issue with film.  
Nor is it now an issue with digital capture.
 
I agree with your statement about diminishing returns of the filtering  
technique. While I have been known to shoot over 3,000 jepeg images at a Hindu  
Wedding, when I am doing 'high end" photographs, like commercial/architectural  
work or landscapes fro myself, I shoot RAW.
 
For gosh sakes, the sensor in the Canon 1D Mark II has a linear capture  
range of around 12 1/2 stops with the 20 D sensor within 1/2 stop of that. I  
can't imagine the Digital Rebel sensor is much worse. Or you have the Fuji S3  
with it's single-shot dual layer dynamic range. So what what more can we  
possibly want!!
 
You can then do a luminance compression using dual file processing for both  
ends and layer them together. You can then blend the midtones/highlights  from 
the dark one into the Shadows/midtones of the bright one.....or just do  more 
than one exposure on a tripod to be combined/processed/post filtered later.  
You can then use the High Dynamic Range (HDR) features in Photoshop CS2 to 
make  whatever image you want. Couple that with post processes involving  
Hue/Saturation methods, gradient mapping, curve manipulations, etc. and you have  
more ways of controlling B&W than we ever had with colored filters on  various 
pseudo-panchromatic emulsions.
 
It's the same technique that musicians use to "Get to Carnegie  
Hall".....practice, practice, practice!!
 
Claude







[Non-text portions of this message have been removed]

> 
> ... the sensor in the Canon 1D Mark II has a linear capture
> range of around 12 1/2 stops with the 20 D sensor within 
>1/2 stop of that. I can't imagine the Digital Rebel sensor is much worse. 

For what I do the Rebel is good for about +3 and -3 stops -- 6 stops total.
Sure, the shadows can go on for longer, but the image quality is not up to
what I want (due to noise).  If I want to do any expansion of the contrast
in shadows, I'm making sure those shadows are not lower than -3 stops.

That said, according to my Pentax spot meter, most of the shots I took this
last week with the Rebel were within that range.  I have not processed them
yet to see the results, however.

>... or just do more than one exposure on a tripod 

That was exactly what I did most of the time when the Pentax read more than
6 stops.  The problem with this is that some scenes do not lend themselves
to multiple exposures.

I found in testing just before leaving that the Heliopan KR15 resulted in
better +3 and -3 detail.  I used the KR15 with a polarizer a lot this last
week, so I'll be curious how they compare to the shots with no filtration.

As a practical matter, I found myself using what is essentially an orange +
polarizer just as I would with B&W film, the difference being the KR15
(wratten 85b -- called "amber") has smooth gradients as opposed to the sharp
cutoff of the B&W filters.

>...
> You can then use the High Dynamic Range (HDR) features in Photoshop CS2 to
> make  whatever image you want...

My early experiments make me think manual merging might be better for large
prints.

I'll be reporting on how the little Rebel did in future posts.  It sure was
fun in any case.

Paul
www.PaulRoark.com

> For what I do the Rebel is good for about +3 and -3 stops -- 6 stops
total.
> Sure, the shadows can go on for longer, but the image quality is not
up to
> what I want (due to noise).  If I want to do any expansion of the
contrast
> in shadows, I'm making sure those shadows are not lower than -3
stops.
> 
Assuming the Rebel XT (350) is not very different from the Rebel
(300), you might find some benefit in trading shadow resolution for
dynamic range. Combining (averaging) pixels with your favourite noise
reduction algorithm, but only doing so in the shadows.  (I use Picture
Window's advanced sharpen together with luminance masks, for example,
but each to their own.)  From memory film resolution is so good in the
shadows so trading off resolution against noise may give acceptable
results.  Of course you perhaps tried this and rejected it already.

Ken