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Edwin,Quote:
Originally Posted by Edwin Beckenbach
I use the formula 1800 / f/stop to estimate diffraction limited resolution. That comes to 28 lp/mm for f/64, which is indeed closer to 20 lp/mm than my figure of 40 lp/mm.
That allows approximately a 2X magnification to stay within the limits of the threshold of human resolution when viewing a print at ten to fifteen inches from the eye.
Sandy
Agreed. I use 1500/ f which is slightly more conservative. Regardless, I can't see any good reason for scanning f64 beyond 1200 or 1500 dpi (2x the image resolution) because there isn't any more image to resolve. I get visible softness in 16x20 enlargements from 4x5 at f64, quite acceptable in my opinion but also clearly noticeable.
Quote:
Originally Posted by sanking
I agree. I was making a distinction, however, based on image feasibility. If I visualize an image such that it would live or die on its sharpness, and if it was true in that case that the aperture I needed to provide vizualized depth of field was too small to support that sharpness, then I would have to conclude that my vizualization was infeasible. I may have to choose between my visualization and my desired print size. My usual choice is to use the smaller aperture and limit print size.Quote:
Originally Posted by sanking
Rick "agreeing with the weakest link analysis but suggesting that one way to address a weak link is to lighten the load" Denney
Quote:
Originally Posted by sanking
There is a lot more to scanning than resolution or sharpness. A LOT MORE. In fact I learned this in part from experience and in part by reading Lenny's writings about this on this and other discussion boards.
I would actually be willing to bet that the drum scan would be much sharper and would require much less software sharpening. And the tonality, especially the separation of mid tones, will be far superior on the drum scanner.
I've noticed this when comparing my drum scans to my Epson scans. And I have a lowly Howtek HR8000, not a fancy-pants Aztek.
I often shoot my 4x5 lenses at f/32. And I print 40x50. Are the results as sharp as when I shoot at f/22 or f/16? No of course not, it would contradict the science. But are the photos better because everything I wanted in focus was in focus and there are no distracting soft areas in the background or foreground? Of course.
Careful Sandy, thinking, in this thread, represents unorthodoxy, and will only invite derision,scorn, and tantrums. I'd reckon 28 lp/mm might represent the very best result possible for f/64, and other factors might conspire to lessen that number. It's possible that a V750, far from being a bottleneck, in this case, could be up to two times overkill.
64.8 mp, as I mentioned earlier in this thread, and that's being generous.
I'm glad some sense is finally being talked in this thread-
It's lonely being a non believer-
Uniform sharpness is a valid ambition for a picture, but at the sizes mentioned, it might end up being uniform unsharpness.
Which is fine too, if that's what you want-
I have a real good idea what scanning is, and the fact of the matter is that there are times when you won't get better image quality with a drum scan than with a lowly Epson V700/V750. Of course there is more to scanning than resolution, but resolution and dynamic range are very important based on my own comparisons, which involves scans with several different drum scanners and several different CCD type scanners. And my conclusion is that if one insists that a drum scanner will always give better final image quality at a given print size, regardless of the characteristics of the negative and scanning parameters, then I am not going to hesitate to remark that the emperor is walking through town naked, because in my opinion that is nothing but BS. It is simply ludicrous to insist that you always need a drum scan for optimum print quality. You don't, and that is a fact.Quote:
Originally Posted by Noah A
Sandy King
I think the drum scan would also have significantly better shadow detail. And less color fringing too.Quote:
Originally Posted by Noah A
Although Lenny did not specifically state this at the beginning of this thread I am fairly certain that he was talking about B&W film, so color fringing would not be an issue. And assuming the B&W negative was not over-exposed or over-developed, which I doubt Lenny would do either, I have my doubts that a drum scanner would give better shadow detail than a V700/V750.Quote:
Originally Posted by Greg Miller
Sandy
This may sound like mumbo jumbo, but.........here goes. I've been using an Epson 750 since they first came out and Imacons for over ten years. I think I am pretty good with them. Now I manipulate the tones in my b&w images allot-I like allot of drama in my prints. Anyway, I have noticed that with good drum scans (I haven't tried them all, but Lenny's are the best I have ever gotten) that I can achieve the look I am after with far less work and more importantly with less artifacts. An example is the enhanced noise at transitions between tones when you darken what were blue skies allot-you get the noise at the edge of the lighter tones along the horizon. With a good drum scan I can get much better transitions than with either the Epson or the Imacons-I've seen this with Imacon scans from pro operators too. That increased separation Noah mentioned above means something real in my world.Quote:
I would actually be willing to bet that the drum scan would be much sharper and would require much less software sharpening. And the tonality, especially the separation of mid tones, will be far superior on the drum scanner.
There is an image I am working on right now that I first scanned on the Epson 750, then I scanned it on an Imacon, then I had it scanned by an Imacon pro at a lab and finally I sent it to Lenny to be scanned and finally then it processed like a dream. Now maybe this is just my weird workflow-how hard I push the tones. But to me the drum scan magic is real.
I will disagree about the shadow detail. If there is detail in deep shadows, a drum scanner will pull it out better. In fact, the only photo in my first book that was rejected by my publisher was a 4x5 transparency that had been scanned, by an Epson, that could not pull out enough properly exposed shadow detail (there were shadows (not particularly deep) and the shadows had detail). That photo was re-scanned by a drum scanner (and did not require any significant or abnormal processing - meaning that the scanned image and transparency looked quite similar).Quote:
Originally Posted by sanking