I just uploaded a series of test scans with my Epson V700 of a 4x5 picture of a railroad bridge, taken with my Nikkor-SW 90/4.5 at f/16 or f/22, probably f/16. This is an exceptionally sharp lens. Hence, my tests might not be indicative, as the resolution of the 4x5 is so sharp. I've read that the 1/R formula underestimates final resolution when one component has much more resolution than another, and works best when both components of the system are of nearly the same resolution.
In any event, from my eye, at least when given a very sharp 4x5 to begin with, it seems from my scans that the V700 can produce very good 10x enlargements as seen on screen (this is about in line with estimates of the true optical resolution of the V700 being about 2400 dpi, which would suggest 8x enlargements at 300 dpi if you don't have much loss of image quality due to 1/R). But that's just from what I see; maybe those scans don't look nearly as good to you guys.
Given a negative that has exactly the same resolution as it seems the V700 has, about 2400 dpi (47 lp/mm), we can expect the final scan to be of a quality of about 23.5 lp/mm (1193.8 dpi, which can produce about a 4x enlargement, or 20x16 print). This is in line with what I've usually seen as suggested for the capabilities of the Epson V700.
Just a parenthetical note, I've seen Lenny Eiger claim that the V700 or V750 has a resolution of about 1100 dpi or something like that, and others argue that such is wrong, and the resolution is 2400 dpi. I think I remember Lenny saying he'd seen those estimates of 1100 dpi from prints made from a V750 or V700 scanner at an Aztek lab. The preceding paragraph would explain the discrepancy between 2400 dpi and 1000 or 1100 dpi. The actual resolution of the scanner component is 2400 dpi (47 lp/mm); however, when scanning in something that is also 47 lp/mm, the 1/R law is probably pretty accurate, so final resolution drops to 23.5 lp/mm (1194 dpi). If that's the case, it explains the discrepancy between Lenny's estimates of the V700 / V750's resolution, and estimates made by others.
I will be sending another copy of the 4x5 that I scanned in to Lenny to scan in at the beginning of December (after I find out if it was accepted in a photo-show). Then I will upload a crop of the same section. If I make a print for the show, of course I'll print from the drum-scan.
It is not that complicated to roughly estimate resolution of a lower end scanner like V700 or Microtek M1/F1 - just take a nice sharp 35mm slide, have it scanned by a good lab with something like Nikon Coolscan 5000 at 3000 - 4000 spi (drum scan is not necessary I think). Then make a scan with you flatbed at whatever spi you think is MORE than the scanner will deliver (2400 spi may be a good start). Make the scan the best you can - then resize the lab scan to the same resolution (2400 spi assumed here) and compare. Do not hesitate to post process both images. If your flatbed scan is obviously less sharp - resize now both scans to 2000, 1600 ,1200 and keep comparing. At some point the difference will start to disappear.
Of course - the best is to make few prints from both scans at different sizes - just find the border when the flatbed scan will not deliver the same as lab scan or it just will not be good enough for you (I assume that happens faster than the slide runs out of data - somewhere about 8 - 10x enlargement)
Once my Microtek F1 is back form service - that's what I plan to do.
Matus
I think you are being too kind. If Aztek lab tested the V700 or V750 and only observed 1000-1100 ppi they either had a defective machine or conducted a faulty test. My testing of the V700 with a high resolution target, after adjusting for plane of best focus with the document type selected, returned a resolution of 45 lp/mm (2286 spi), where resolution is determined visually with discrimination of both horizontal and vertical lines, and about 65 lp/mm (3300 spi) when discrimination is seen in only the horizontal or vertical line pairs.
Sandy King
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Sandy,
Have you ever tested the resolution of your Eversmart Pro scanner?
Bruce
Bruce,
Sure, see the attached file. In my test of the Eversmart Pro I got effective resolution of about 65 lp/mm (3300 ppi) with line discrimination in both the horizontal and vertical, and about 90 lp/mm (4500 ppi) with discrimination of the pair lines in only one direction.
Sandy
Last edited by sanking; 23-Nov-2009 at 21:05.
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I make the scans and postproduction for Massimo Vitali.
Take a look:
http://www.flickr.com/photos/castorscan/
I've done a lot of scanning on both my Howtek drum scanner and on rental Hasselblad scanners. I was recently hoping to sell the drum scanner since I thought renting the hassy X1 would leave me with less overhead expenses. But upon close inspection there is a big difference between the scans so I'm hanging on tight to the Howtek.
There is a slight resolution advantage to the drum scans. I'm using an HR8000 and scanning at 4000dpi for a 1.5gb file. It's no surprise that the drum scan is sharper, the X1 maxes out at a claimed 2040 dpi for 4x5 film. But resolution is the easy part.
The drum scanner tends to minimize film grain. This is partially due to the wet mounting but has more to do with the fact that you can vary the scanning aperture. If you choose the correct aperture, it will make the grain less obvious while still maintaining sharpness and maintaining the character of the grain and the inherent look of the film.
Even more importantly, at least in my experience, the drum scanner is better at capturing a full range of tones and colors. As I said, resolution is the easy part, but getting a scan with good separation of tones throughout the range is more difficult.
A Hasselblad/Imacon scan is certainly good enough for a 40x50" if it's all you can afford. But after you consider the high costs of printing, mounting and framing a 40x50" print, it doesn't make sense to cheap out on the scans.
Last edited by Noah A; 7-Feb-2012 at 05:04. Reason: Typo
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