Page 1 of 5 123 ... LastLast
Results 1 to 10 of 50

Thread: Epson V800 2400ppi Only After Down Sampling From 6400ppi

  1. #1

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    569

    Epson V800 2400ppi Only After Down Sampling From 6400ppi

    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.

  2. #2

    Join Date
    Sep 2014
    Posts
    189

    Re: Epson V800 2400ppi Only After Down Sampling From 6400ppi

    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

  3. #3

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    569

    Re: Epson V800 2400ppi Only After Down Sampling From 6400ppi

    What method are you using to downscale

  4. #4
    Alan Klein's Avatar
    Join Date
    Jun 2015
    Location
    New Jersey was NYC
    Posts
    507

    Re: Epson V800 2400ppi Only After Down Sampling From 6400ppi

    Trust your own eyes.

  5. #5

    Join Date
    Dec 2013
    Location
    Nashville
    Posts
    506

    Re: Epson V800 2400ppi Only After Down Sampling From 6400ppi

    Quote Originally Posted by IanBarber View Post
    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.
    Quote Originally Posted by Alan Klein View Post
    Trust your own eyes.
    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.

  6. #6

    Join Date
    Sep 2014
    Posts
    189

    Re: Epson V800 2400ppi Only After Down Sampling From 6400ppi

    Quote Originally Posted by IanBarber View Post
    What method are you using to downscale
    Just a simple downscale in GIMP.

  7. #7

    Join Date
    May 2017
    Posts
    232

    Re: Epson V800 2400ppi Only After Down Sampling From 6400ppi

    Quote Originally Posted by IanBarber View Post
    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 haven’t seen much difference when I have tried it but I am curious to hear from others who may have.
    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.

    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.

  8. #8

    Join Date
    Dec 2013
    Location
    Nashville
    Posts
    506

    Re: Epson V800 2400ppi Only After Down Sampling From 6400ppi

    Quote Originally Posted by Ted Baker View Post
    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.
    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.

  9. #9

    Join Date
    May 2017
    Posts
    232

    Re: Epson V800 2400ppi Only After Down Sampling From 6400ppi

    Quote Originally Posted by faberryman View Post
    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.
    I think that's kind of what I just said...

    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...

  10. #10

    Join Date
    Dec 2013
    Location
    Nashville
    Posts
    506

    Re: Epson V800 2400ppi Only After Down Sampling From 6400ppi

    Quote Originally Posted by Ted Baker View Post
    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 faberryman View Post
    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 View Post
    I think that's kind of what I just said...
    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.

Similar Threads

  1. Epson V800 - VueScan - MAC OSX Question
    By IanBarber in forum Digital Hardware
    Replies: 2
    Last Post: 24-Jan-2017, 09:25
  2. Epson V800 Scanner Capabilities
    By IanBarber in forum Digital Processing
    Replies: 11
    Last Post: 11-Dec-2016, 13:03
  3. Epson V850-Epson V800, what is the next step up.
    By Smorton in forum Digital Hardware
    Replies: 21
    Last Post: 1-Jul-2016, 10:31
  4. Epson V800 - Epson Scan Vs Silverfast
    By alanmcd in forum Digital Hardware
    Replies: 67
    Last Post: 4-Apr-2016, 09:21
  5. Epson V800 & V850. thoughts?
    By yuexiachou29 in forum Digital Hardware
    Replies: 10
    Last Post: 28-Mar-2015, 11:47

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •