digital 21 megas shot versus 6x9 cm slide film scanned

Scanning takes a lot of time so I don't want to find myself in a situation where I have to scan a negative again to make a larger print. So I scan it the first time at as high a resolution in spi as practical, determined by computer processor speed, disk storage space, etc. so that all (or as much as possible) of the detail is captured. With medium format negatives of 6X7 cm or 6X9 cm one generally has plenty of speed and storage space to scan at the highest optical resolution. What I then do is make all of the corrections on this master file and archive it. I can then downsize it to whatever I want for printing.

As has been mentioned before, some of the high quality medium format optics can resolve 100 lp/pm so even a scan at 4000 dpi will not necessarily capture all of the detail in a negative made on high resolution film like Tmax-100 or Acros.

Sandy King

Scanning takes a lot of time so I don't want to find myself in a situation where I have to scan a negative again to make a larger. So I scan it the first time at as high a resolution in spi as practical, determined by computer processor speed, disk storage space, etc. so that all (or as much as possible) of the detail is captured. With medium format negatives of 6X7 cm or 6X9 cm one generally has plenty of speed and storage space to scan at the highest optical resolution. What I then do is make all of the corrections on this master file and archive it. I can then downsize it to whatever I want for printing.

As has been mentioned before, some of the high quality medium format optics can resolve 100 lppm so even a scan at 4000 dpi will not necessarily capture all of the detail in a negative made on high resolution film like Tmax-100 or Acros.

Sandy King

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Originally Posted by renes

Explain it please: if you want to have 20x28" (50x70cm) enlargement from 6x9 b&w film scanned on drum in 4000dpi (its highest resolution), you will get much bigger enlargement, will you? For 50x70cm size a sufficient ans appropriate resolution is 2300dpi. Is it better to scan it in 4000dpi and to scale the file later to 50x70cm size (with some lost resolution and details) than to scan the film in 2300dpi without scaling? Which scanning method is better and why?

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I scan 6x7's at 8000. I get a 2.2 Gig file. It is better to not scale files at all. I'll keep this all in inches, as dpi is in inches... 2300 dpi x 2.75 inches (7cm) is 6325 pixels. 6325 divided by 28 yields a dpi of 225. This is not sufficient for full quality.

28 in print * 300 dpi would be a total of 8400 pixels. 2300 (6325) is not enough. I agree with Sandy that you don't want to scan again when you decide you want a 37in print, you want to archive it... My file (2.75 * 8000) yields a total of 22,000 pixels. Divide that by 300 and you can make a 73 inch print, or a 36 inch one at 600 dpi. I like more than 300 dpi to the print, for b&w especially.

Scaling up is not a good idea. Scaling down can be, when one is sharpening smaller images. However, for printing a decent sized print it is not usually necessary. I refuse to believe that the printer prints any better at 300 or 363 than it does at 422.5, for example.

I have a Mamiya 7 II and I agree, the lenses are phenomenal....

I hope this helps explain a few things.

Lenny

Thank you all for clear explanation.

One more question: if one flatbed sanner's true attainable optical resolution is 2000dpi (i.g Epson 4990), is it good not to surpass it when seting it in scanner's soft to get best film scan performance?

It's not quite clear to me when the flatbed scanner achieves its highest optical resolution during scanning: when it's set at 2000dpi (same as optical resolution), higher, or at highest resolution available in scanner's soft (i.g. 9800dpi) ?

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Originally Posted by renes

It's not quite clear to me when the flatbed scanner achieves its highest optical resolution during scanning: when it's set at 2000dpi (same as optical resolution), higher, or at highest resolution available in scanner's soft (i.g. 9800dpi) ?

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Depends on the flatbed. The Epson V700, if you use the sharper lens that is engaged when you select film holder, delivers resolution of about 2000 dpi if you scan at 2000 dpi. If you scan at 6400 dpi you will get real resolution of about 2400 dpi. So you do gain some resolution by scanning at the highest possible optical setting, but not much. However, if you have the time and disk space you will get the best scan by using the highest optical setting, then reduce the file size to 2400 dpi.

High end flatbeds, like the Eversmarts and Cezannes, do a much better job in that real resolution is 90% or more of optical resolution. The optical resolution of my Eversmart Pro is 3175 dpi, and tests of targets shows that it delivers almost 100% of that figure.

Sandy

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Originally Posted by sanking

Depends on the flatbed. The Epson V700, if you use the sharper lens that is engaged when you select film holder, delivers resolution of about 2000 dpi if you scan at 2000 dpi. If you scan at 6400 dpi you will get real resolution of about 2400 dpi. So you do gain some resolution by scanning at the highest possible optical setting, but not much. However, if you have the time and disk space you will get the best scan by using the highest optical setting, then reduce the file size to 2400 dpi.

High end flatbeds, like the Eversmarts and Cezannes, do a much better job in that real resolution is 90% or more of optical resolution. The optical resolution of my Eversmart Pro is 3175 dpi, and tests of targets shows that it delivers almost 100% of that figure.

Sandy

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But the higher resolution is chosen, the more USM need to be used for sharp image?

I konw you have tested a few 4990 scanners and got 1800 effective resolution. Did you reach this amount when set-up epson scanning program at 1800dpi or at higher dpi?

Quote:

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Originally Posted by renes

But the higher resolution is chosen, the more USM need to be used for sharp image?

I konw you have tested a few 4990 scanners and got 1800 effective resolution. Did you reach this amount when set-up epson scanning program at 1800dpi or at higher dpi?

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I don't find that more USM is needed to get a sharp image when you scan at high resolution. In fact, I don't use any sharpening when scanning.

Can not recall the details of testing the 4990. That was a long time ago and I apparently did not save ay of the test scans. However, in general all of the Epson scanners work about the same. You get maximum detail by scanning at the highest possible optical resolution, but in many cases there is very little difference in scanning at about 2000 dpi and 4800 or 7400 dpi. As I mentioned earlier, you gain some by scanning at the highest resolution, but the percentage increase is small and may not be worth your time and effort.

Sandy

Question:
- Anyone have experience w/ the Epson Expression 10000XL- Photo Scanner ?
- How much better, or is it? than the Epson Perfection V750-M Pro ?

I have no idea but considering the price for scanner and optional transparency unit I wonder if it might be better bang for the buck to look for a used Eversmart or similar.

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Originally Posted by buggz

Question:
- Anyone have experience w/ the Epson Expression 10000XL- Photo Scanner ?
- How much better, or is it? than the Epson Perfection V750-M Pro ?

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The optical system of the V700/750 is as good, if not better, than that of the 10000XL. But to get the most out of the V700/750 you have to adjust the height of the holder above the glass to make sure focus is correct. You can not adjust focus with the V700/750 with software as it is fixed. The Epson 10000XL can be auto-focused or manually focused through the sofware driver. This is a big advantage since you can get sharp focus automatically regardless of the position of the negative in relation to the base glass.

Sandy