----- Original Message ----- From: "Jens Bladt" Subject: RE: all about the glass
> In the days of no digital photogrphy, the lenses would set the limits to > resolution, sice film can resolve more than 100 lp/mm. Not many lenses can. > Today, as digital technology gain market shares, the sensors seem to be > setting the limits to resolution. The sensors cannot yet utilize very high > quality lenses. The sensor technology still have to develop further in orfer > to reach 100 lp/mm, or whatever is equals 35mm negatives (3600 linepars > across the long side of the image = 3x3600 = 10.800 pixel). This should > mean, that in digital photography - it's all about the sensors, not the > glass! This debate, of course, ignores all lens qualities other than resolution, and has to ignore resolution vs. subject contrast to work. Since you cannot ignore subject contrast when discussing film and lens resolution, the numbers stated are deceiving. Pray tell, what film can resolve more than 100 lp/mm? I haven't found one yet that will do it without the help of a 1000:1 target. Velvia 50 does 80, I expect that's about as good as it gets, maybe Tech Pan can do a bit better, but it's not well suited to colour photography. Lenses, OTOH, when used for pictorial purposes, don't usually get much more than 60 lp/mm resolution. One thing I have never seen answered definitively is this: Do digital sensors also lose resolution as measured in lp/mm when subject contrast drops? And if so, by how much? It seems to me that sensors wouldn't be as sensitive to subject contrast, but I don't know for sure. Anyone? I believe Rob calculated the istD sensor resolution to be somewhere around 43 lp/mm or some such. If sensor resolution can be brought up to 60 lp/mm and made full frame, then you are pretty much at a film equivalent for raw resolution, and have a tremendous advantage over film WRT granularity. This takes the lenses out of the equation, and ignores colour aberrations. No comparison is really perfect. William Robb
