Digital BW, The Print

Hi Steve,

Hope Clayton doesn't mind my jumping in on this discussion, too...

Yes, sensors do display a linear response to incoming light, but that response is more like negative film than slide film. Additionally, because the sensor doesn't have a "toe" or "shoulder" to its "characteristic curve" you actually realize better results on both ends. I'm not sure about the prosumer cameras like the Canon Pro1, but with high-end equipment like the Phase One P25 back, Betterlight scan back, and probably the new Canon 1Ds you're looking at 10 - 12 stops of dynamic range. Throw in the fact that you have very clean images to work with (no grain, etc) and our old measurement factors start to crumble. FYI, from what I've read the new Phase One P25 back (22 megapixels) is seriously challenging drum scanned 4x5! I don't know this for fact because I don't own one, but it certainly gives us an idea of where this technology is header. Hopefully, someday this top-o-line equipment will be affordable to the average consumer.

Alan Huntley

> 
> From: "Stephen Kobrin" <kobrins@...>
> Date: 2004/12/09 Thu AM 08:36:30 EST
> To: DigitalBlackandWhiteThePrint@yahoogroups.com
> Subject: [Digital BW] Re: Digital camera again
> 
> 
> 
> >  We must try to achieve the desired results with software after the
> > fact.  I was a dedicated Tri-X user, and found I could not get the
> > Tri-X "look" no matter how hard I tried.  I could emulate the 
> spectral
> > sensitivity, but could not imitate what the Tri-X grain gives an
> > image.  BUT, I also found I could "get over it" and learn to like 
> what
> > I do get.  So basically you have to let go of the past. 
> 
> 
> Hi Clayton,
> 
> Resolution aside, I worry about two problems with digital capture for 
> B&W.  First, as I understand it, a digital sensor reacts much like 
> slide flim: a range limited to about five stops and a need to expose 
> for the highlights.  Second, again as I understand it (and I may not!)
> the chip's sensitivity is linear while the progression of f stops is 
> not. Thus, close to half of the chip's "range" (not a technical term) 
> is taken up by the widest opening and by the time you get to the 
> fifth and smallest stop, not much is left.  The net effect of both of 
> these issue should be a constraint on tonal range and a loss of 
> detail in the shadows, vis-a-vis film.  
> 
> Am I wrong?  Have you found this to be a problem?