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I have read on numerous websites that the V800 in reality only produces an effective resolution of around 2400ppi. This I can accept but I also stumbled across another article which claims that in order to arrive at 2400ppi, you really need to be scanning at 6400 and then down-sampling in say Photoshop.
Has anyone done any testing to confirm this. personally, I havent seen much difference when I have tried it but I am curious to hear from others who may have.
I would not be surprised if this is true, it seems the limitation with many of these scanners is the optics. Quite some other scanners have the same issue.
For 35mm have a Plustek 8200 scanner and it behaves the same, i scan at full reso (7200dpi iirc) and then downscale the resulting image afterwards to 4330x2880 (largest 3:2 image on a 5k monitor). The resulting file is noticably sharper then having selecting a lower resolution directly in Silverfast
What method are you using to downscale
Trust your own eyes.
Quote:
Originally Posted by IanBarber
filmscanner.nfo tested the V800 and found that it achieved its maximum resolution of 2300 when scanned at 4800. Scanning at 6400 increased the file size but not the actual resolution. I trust the testing rather than my own eyes because I do not have a USAF resolution chart to conduct my own testing. I don't downscale my files until printing. Storage is cheap.Quote:
Originally Posted by Alan Klein
Just a simple downscale in GIMP.Quote:
Originally Posted by IanBarber
AFAIK the test method for scanners simple takes the effective size between pixel, and divides it by 1 inch. In the case of V800 the sensor size is 1/3200 inch and then by overlapping two rows of sensors you get 1/6400 on an inch.Quote:
Originally Posted by IanBarber
The 2400dpi or what ever is just some made up test using a target and your own eyes, not a bad idea really :-)
For my own tests with my 4990 scanning at the "highest resolution" 4800dpi results in the best scan, but 2400dpi is actually very close, and is much quicker.
When I do scan at 4800dpi I use the Lanczos resizing algorithm, to resize, there is definitely a small difference.
The manufacturer's resolution numbers are just the resolution of the CCD chip, and do not include the optical and mechanical systems. The actual test resolution is always lower, typically 50% lower.Quote:
Originally Posted by Ted Baker
I think that's kind of what I just said... ;)Quote:
Originally Posted by faberryman
However in order to get that 50% lower amount, it is necessary to use the system as it best. If you use it slightly less than its best you might end up with 55% lower amount...
Quote:
Originally Posted by Ted Baker
Quote:
Originally Posted by faberryman
You said that it was a "test method". I was just pointing out the it is not a test method, but a recitation of CCD sensor specifications by the manufacturer. Some manufacturers add insult to injury by also adding software interpolation to the CCD sensor specification. It is how Reflecta (Pacific Image), for example, gets to a resolution of 10,000 from a scanner that is only capable of an actual resolution of 4100. (Still very good for 35mm, but not as advertised). That is why it is important to seek out actual test results when selecting a scanner, to determine 1) actual resolution, and 2) scan resolution to achieve actual resolution. I think we are in agreement of these points.Quote:
Originally Posted by Ted Baker