I just realized I meant to post this in the Digital Hardware forum and accidentally posted in Digital Processing. Sorry about that! Moderator, feel free to move it if you want.
MODERATOR'S NOTE: done, no problem!
I just realized I meant to post this in the Digital Hardware forum and accidentally posted in Digital Processing. Sorry about that! Moderator, feel free to move it if you want.
MODERATOR'S NOTE: done, no problem!
Last edited by Oren Grad; 14-Aug-2017 at 08:54.
When I started work on a dslr scanner, I had a D200. Cameras now are much better. If you're just scanning large format, then a system that takes 4 or so pictures of the negative should suffice for a lot of purposes. Making a manual positioning system is much easier than building an electronic positioning system. I used a thick glass plate that I slide a negative carrier on to do this, but there are a lot of ways. I recommend anyone thinking about building a dslr system do that first. It's probably all you need. If you need really high quality for 35mm, then a fancier system would be preferable.
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
Epson Expression 12000XL Photo Scanner then Imacon or a drum scanner like the Aztek 8000
In this link there is an Aztek/Howtek HR 8000 for $8800
http://cresimaging.com/filmflatbeddrumscanners.html
but I haven't been able to find anyone who has actually tested the real world performance.
Hello from France
A French photographer living close to where I am has tested (in Dec. 2014) the real world optical resolution of a freshly acquired V850 scanner with two tests targets, a Silverfast target on film and a USAF-1951 type of target, from Edmund optics, metal strips on glass.
Results obtained with the glass target where a bit difficult to understand, probably the reflectivity of the metal-on-glass target is too high for the scanner and tends to generate a lot of parasitic stray light.
Reading with the Silverfast target, he found an actual resolution limit of the V-850 between group 5/4 and group 5/6 according to the USAF numbering, this yields something between 2299 dpi and 2896 dpi i.e. an actual optical resolution limit between 45 and 55 cycles /mm.
As a comparison, similar measurements for the V-750 have been reported here, between 2148 and 2163 dpi, the resolution improvement looks marginal for the V-850 w/respect to the previous V-750.
http://archivehistory.jeksite.org/ch.../appendixc.htm
In both cases, a lower resolution is found in the scanning (vertical) direction.
Optical resolution limits as claimed in the manufacturer's data sheet for the v-850 could not be achieved in this test, this is another question I'll not address here.
Details of the discussion (in French) are here, dated Dec. 2014
45 to 55 cy/mm is not so bad for large format photography!
You can check on this lens test article by Chris Perez, 60 cy/mm @f/22 is not uncommon, but higher resolution figures for lenses covering LF are quite rare.
http://www.hevanet.com/cperez/testing.html
However, this figure of 50 cy/mm is the minimum resolution limit anybody could achieve through a direct optical enlargement, with a good enlarging lens, 40 years ago!!
However, if you consider that 4.5 to 5.5 cy/mm yields a high quality print from a human visual point of view, the Epson V-850 will allow you to print up to a 10X magnification ratio; from a 4x5" image this yields a 40x50" print, which is more than sufficient for many applications!!
A test of multiple units of new V800, V850 and even thrown in some V750 in good condition would be really interesting to see. I believe the amount of variability between the new units would be surprising. Kind of like how good lens tests utilize more than one copy of a lens.
Doug
www.BetterScanning.com
I think most people get the v850 over the v800 because of the second set of film holders, a special mount adapter for keeping film flat (haven't seen this so I dont know what it looks like), and Silverfast SE Plus 8 (vs the Silverfast SE 8 that comes with the v800)
For $160 I would say the holders alone would justify the price but that's if you need them.
What I find more important is to figure out the optimum film holder height for whichever scanner you choose. Especially if you plan on printing.
I think I just plain get better scans with the IQsmart than I ever did with the Epson 750 - resolution is nice but not the whole story. I'd ppossibly do even better with a good drum scanner, but the workflow with the IQsmart is much simpler.
The V850 comes with a Silverfast version that includes MultiExposure, this feature is critical to obtain better deep shadows with Velvia/Provia, this is a major advantage. For the SE (without "Plus") version normally you can purchase that software function separately for V800 as normally it does not include ME.
For BW I see little need for ME, a 2.8D WB negative is something weird, IMHO, and the V800/850 performs excellent at these densities. What's about resolving power I really don't see any need to have more than true 2000 dpi resolving power, a resolving power that V850 reaches easily, this ends in true optical 320 MPix for 8x10, this is 160 times the information a Full HD monitor can display.
For prints beyond 3.3m wide (from 8x10) it can be interesting having a better scanner if prints are to be viewed from reading distance. For 4x5 a better scanner can be useful for prints beyond 1.65m wide (if the shot is technically perfect).
Under those sizes a V850 fullfills printer requirements, being more resolution a waste of 16 bits edition time, as even today's PCs get sluguish, at least my i7.
Is it multi-exposure or multi-scan? The former is taking many readings at one position. The latter is doing multiple scans of the whole negative. The first way is better, as a lack of registration with the other way can lead to a loss of sharpness.
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
I seem to recall the Epson flatbeds are only compatible with multi-pass scanning (regardless of whether the software calls it ME or MS) and do have enough problems with registration to make it basically useless.
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