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Thread: question about using the 4x5 Epson scanner lens to scan 5.9" wide and stitch 8x10

  1. #31

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    Re: question about using the 4x5 Epson scanner lens to scan 5.9" wide and stitch 8x10

    Quote Originally Posted by Sasquatchian View Post
    but what evidence do you have that Howtek did anything like this in firmware?
    With all user level sharpening disabled, we have found shots that are sharper in the howtek scan than in the microscope inspection of the film, me... I've no doubt, but it can be checked by producing a set of CMS20 negatives portraying edges at different contrasts, and with different CoC, and cheching when edges are improved.

    I fact it would be stupid not implementing a certain degree of sharpening in firmware because this allows a huge speed vs quality benefit in the machine to computer communications. This allows an oversampling_the_medium+sharpening+ downsampling_to_required_size cycle that improves quality a lot and it does not not overload the computer and the communications.


    Look, "in firmware" sharpening has huge technical benefits, and this is one of the strong points of very Pro hardware.


    In the same way one has to understand that the not Pro V700 scans have to be optimized in Ps before they are compared to result of a Pro scanner, because Epson does not that process with that efficiency.

  2. #32

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    Re: question about using the 4x5 Epson scanner lens to scan 5.9" wide and stitch 8x10

    Quote Originally Posted by Michael Roberts View Post
    I've been reviewing the scanning threads but have not found any posts from anyone who has actually done this--so if you have experience with it, I would appreciate hearing from you.

    From what I've found, the actual resolving power of the 8x10 film area guide lens on the Epson 4990/V7xx/V8xx scanners is only around 1,600-1,800, but the dual higher resolution lens used for 4x5 and smaller is about 2,300. The higher rez lens only scans 5.9" wide, however.

    A few have suggested the higher rez lens could be used to scan two sections of an 8x10 and then the two scans could be stitched together in PS to achieve a 2,300 8x10 scan.

    I have also shot quite a few 5x8 and 4x10 images--two of each on one 8x10 sheet of film--and theoretically could scan these with the higher rez lens in one pass if it's possible to rig up a holder to position the film for the higher rez lens. Similarly, I could do a 60% crop of an 8x10 in one pass (5.9/9.8).

    Anybody have experience using the higher rez lens with an 8x10 sheet of film? If so, would you please share your process? Is it even possible to "trick" the scanner into scanning part of an 8x10 sheet of film using the higher rez lens? Doug indicates in this post that it is possible simply to select the high rez lens with the software, but that still leaves open how to get the correct calibration: https://www.largeformatphotography.i...=1#post1487198

    I have an older 4990 that only has the lower rez lens. I'm wondering if it would be worth it to upgrade to the V700 or later model. I would only want to upgrade if I can use the higher rez lens for scanning 8x10 in sections (assuming stitching).

    Thanks!
    Michael
    I have a 4990 I found the optimum focus is slightly above the glass. Mine was about 1.5m, I think, FWITW... With a wide lens, the depth of field is not as critical as the longer lens that the v700/800 have.

    They had to achieve some compromise in any case because the film holders can not be at 0mm. The V700/800 have two lenses so you have two focus plans for different tasks to choose from. But you still have the same problems just more choices to help solve it, just not all choices to solve all the problems...

  3. #33

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    Re: question about using the 4x5 Epson scanner lens to scan 5.9" wide and stitch 8x10

    Quote Originally Posted by Sasquatchian View Post
    whether something happened in software or firmware?
    Every development team is a different world. What is clear is that in those designs Image Quality would be a concern of different development departments and even of different companies, for example SilverFast is a 3rd party software interfacing scanners.

    From this perspective it is very important that the machine itself makes the sharpening that can be optimally done at that firmware level and it would be difficult to perform optimally in the following processing layers (software development team).

    For example the firmware in the Hasselblad X1/X5 can make a different optimal sharpening depending on the lens magnification, sure the Linos Rodagon inside has a different CoC depending on magnification, and it requires a USM mask with higher radius/factors in the Y direction than in the X direction.

    Also a drum has motion blur that depends on the physics, so it's the machine itself that knows how to do it optimally. Delegating that job to next layers is a mess, not mentioning the chance we want 3rd party software interface the scanner.

    A Pro machine not having a sound internal optimization is disappointing.

    IMHO, the idea is that the firmware should do a sharpening that is related to the physics of the machine, and the user layer sharpening should do anything else.


    Quote Originally Posted by Ted Baker View Post
    I have a 4990 I found the optimum focus is slightly above the glass. Mine was about 1.5m, I think, FWITW... With a wide lens, the depth of field is not as critical as the longer lens that the v700/800 have. They had to achieve some compromise in any case because the film holders can not be at 0mm.
    Yes...
    Last edited by Pere Casals; 15-Aug-2019 at 11:30.

  4. #34

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    Re: question about using the 4x5 Epson scanner lens to scan 5.9" wide and stitch 8x10

    Quote Originally Posted by Jim Andrada View Post
    Hi Michael. I thought I had responded to your question of how to mount 4 x 10 on the Epson but it doesn't show u here, so here goes again

    Just wet mount the 4 x 10 on the carrier glass (the glass carrier that's part of what they call the mounting station)

    This thread seems to have gone off the rails a bit into the tech weeds - I think you were asking a pretty simple straightforward question.

    I solved the question by getting a bigger scanner with focusing ability. I haven't used a larger Epson but...
    Thanks Jim! What I am seeing is the carrier glass is 7.25 x 9.75in, so the film will need to fit inside this area. Seems like 4x10 could be trimmed slightly to fit w/o losing any of the image; could be an issue with fluid leakage, though.

  5. #35

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    Re: question about using the 4x5 Epson scanner lens to scan 5.9" wide and stitch 8x10

    Quote Originally Posted by Ted Baker View Post
    I have a 4990 I found the optimum focus is slightly above the glass. Mine was about 1.5m, I think, FWITW... With a wide lens, the depth of field is not as critical as the longer lens that the v700/800 have.

    They had to achieve some compromise in any case because the film holders can not be at 0mm. The V700/800 have two lenses so you have two focus plans for different tasks to choose from. But you still have the same problems just more choices to help solve it, just not all choices to solve all the problems...
    Thanks, Ted! Good to have more data on the optimal plane of focus for scanning directly on the lower glass.

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