Maybe this has been asked before, some higher end scanner provides very high resolution, but is it really needed? I mean, if the lens used to take the picture has resolution 80 lpmm, which is 80X25=2000 lp inch, if you scan over 4000 dpi, it shouldn't provide more details, am I right?
You are right. This has been discussed many times before, including on this site. Search around and you'll find it. This very question was asked earlier this year I think.
It's a simple question with quite complex answer(s). The search function is your friend.
Bruce Watson
I would like to search for that, can you suggest what key words to search?
If you're getting 80 lp/mm, odds are you're not shooting LF... most LF lenses top out much lower than that, and those that don't tend to be stopped down enough (f/22, 32) to erase their advantage.
Oh, I dunno. How about Max scanning resolution? That'll turn up this thread anyway.Originally Posted by Songyun
There are few questions one can ask that haven't already been answered. Happens to us all. Search is your friend.
Bruce Watson
Hi Songyun,
In my opinion, regardless of how much resolution you get at the capture stage, one would be wise to scan at the highest resolution the scanner is capable of. Capturing and scanning are two different things. Scanning resolution dictates what size you can print at. The higher the resolution, the bigger you can print. Maybe you don't need big prints at present time, but what if you do down the road? Scan once, print many sizes.
bernal
Numbers don't tell the whole story. There are flatbeds vs drums, which scan very differently and need to be treated differently in the post-scan stage. I think the resolution numbers fall apart when you compare 4x5 to 8x10. If you scan them at the same resolution you still get a better print from the 8x10. (Annoyingly.) It isn't all about resolution...
One fellow suggested that the max one could get off an 810 is 72 mgpxls. His numbers for the lens and all may be right, I can't dispute it with my limited knowledge of optics, but the results on the prints are clearly far in excess of that.
I prefer to get plenty of extra pixels just in case the output needs to be larger. I don't like to re-scan, and most of my clients don't like to pay for a second scan, much less do all the photoshop work again for a larger print. I usually scan larger. But there are limits, I don't usually scan an 8x10 to a 24 Gig file. It just isn't needed unless to want to make a huge print, say larger than 10 feet.
There is certainly no reason to scan at a higher resolution that the optical resolution of the scanner. For my drum, that's about 8,000 ppi, for a consumer flatbed, that's in the 2000-2400 range, the lower, in my opinion.
Lenny
EigerStudios
Museum Quality Drum Scanning and Printing
When what you scan compares to what you see on the film through a loupe, then you are at the maximum usable scanning resolution. To go beyond that can sometimes help tonal transitions and large areas of colour. The downside is that scanned file sizes can become quite large, which will slow down the entire process.
One work-flow method is Scan Once, Output Many (SOOM). To do that, you always scan at the maximum hardware scanning resolution of the scanner. Then you archive that result. When you need to send out an image file, or have an image printed, you size the file for the best output match. This can be efficient with high end scanners, but not might be practical with more consumer oriented gear due to their slower speed of operation.
Ciao!
Gordon Moat Photography
Bruce, thanks a lot, now I have something to read first.
Not to be argumentative, but I actually slightly disagree, perhaps it's only rhetorical. The preferred scanner resolution (difficult to actually wrap up in a single term like that) has to do with how much of the detail on the film written to file is desired. This also is difficult to apply a singe term to, because what constitutes "good", or useful detail? Do you want to resolve the optical image, or down to the grain? Rarely the same.
Anyway, accurate description of the film character, including the grain, requires scanner specific settings, rarely not more than 4000ppi in my experience, usually less. Now we have the issues of ccd vs pmt, and aperture... too much for now...
Anyway, describing the film, and print size, are separate issues.
Then, over particular print sizes, more ppi is required to hit printer resolution than is required for accurate film description at the scanner stage. So non-descriptive pixels are going to be manufactured one way or another, and this needn't be a bad thing, in fact it's more often than not a simple unavoidable fact.
Now the question becomes how to get there... make a bigger scan then necessary for the film? Is this done with true optical ability of the scanner or oversampling? Res up various methods, Photoshop or plugins? Or simply let the printer driver/RIP make the larger matrix of dots how it sees fit?
Often we are making scans far bigger then what is necessary to define the detail yielded by our lenses on the film. This may be the best way to get to the desired print sizes, sometimes it makes no difference in my experience. I'm only trying to point out that resolving film image and getting to print sizes are separate issues.
Tyler
http://www.custom-digital.com/
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