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Thread: Epson V850: better optics, *really*?

  1. #21

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    Re: Epson V850: better optics, *really*?

    Quote Originally Posted by Doug Fisher View Post
    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
    This can be noticed perhaps with 35mm film, with new height adjustable holders (of with betterscanning holders ) most of variability should cancelled. I Use a V750 and a V850, both performs equal but the adjustable holder has to be click moved from the V750 to the V850 for same good results in 35mm film.

    But I find that difference totally irrelevant for LF, even for MF...

  2. #22

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    Re: Epson V850: better optics, *really*?

    Quote Originally Posted by williaty View Post
    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.
    V850 and V800 are ME compatible, but used Silverfast version must support ME. Silverfast SE does not support it, but Silverfast SE Plus does support ME.

    ME and Multi-pass are totally different features. ME makes two exposures with different exposure time before moving to next row, to extend dynamic range. Multi-pass make the scan several times and averages a result.

    I find ME really powerfull, but I don't use Multi-Pass.

  3. #23
    Pali K Pali K's Avatar
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    Re: Epson V850: better optics, *really*?

    Quote Originally Posted by Pere Casals View Post
    I find ME really powerfull, but I don't use Multi-Pass.
    Pere, can you post some comparative scans of a dense E6 image with and without ME using Silverfast? Vuescan has this as well and I find that it does absolutely nothing other than add digital gain and brighten the shadows but not really increase detail.

    Pali

  4. #24

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    Re: Epson V850: better optics, *really*?

    Quote Originally Posted by Pali K View Post
    Pere, can you post some comparative scans of a dense E6 image with and without ME using Silverfast? Vuescan has this as well and I find that it does absolutely nothing other than add digital gain and brighten the shadows but not really increase detail.

    Pali
    It will depend on whether your scanner allows software control of the hardware exposure. With VueScan on the Coolscan, for example, I can actually adjust the brightness of the RGB LEDs per channel plus adjust the exposure time. That sort of ME is more helpful though I can't say I think it's actually useful enough to take the time to turn it on. On the Epson, there's no way to alter the physical exposure so it doesn't do much of anything.

  5. #25

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    Re: Epson V850: better optics, *really*?

    Quote Originally Posted by Pali K View Post
    Pere, can you post some comparative scans of a dense E6 image with and without ME using Silverfast? Vuescan has this as well and I find that it does absolutely nothing other than add digital gain and brighten the shadows but not really increase detail.
    Pali
    I'll prepare it, it will take me a while, I've a series of deliverately underexposed shots of this roll https://www.flickr.com/photos/125592...posted-public/ where an awesome difference is seen with ME.


    Quote Originally Posted by williaty View Post
    It will depend on whether your scanner allows software control of the hardware exposure. With VueScan on the Coolscan, for example, I can actually adjust the brightness of the RGB LEDs per channel plus adjust the exposure time. That sort of ME is more helpful though I can't say I think it's actually useful enough to take the time to turn it on. On the Epson, there's no way to alter the physical exposure so it doesn't do much of anything.

    You really are not aware of what ME does with Silverfast. With ME V700/850 scanners deliver a very decent performance for challenging Velvia. With ME V700 improves practical readable density from 3.1 to 3.4, this is in logarithmic terms, in linear terms this is reading half of the light level. These numbers are from LaserSoft web site, IMHO published measurements based in ISO 21550 method are pretty fair.







    IMHO no high end flatbed can deal with dense Velvia without using multiexposure, because Dynamic range of CCD simply comes very short in front of PMT sensors. But this can be solved easily with HDR technique. IMHO high end flatbeds use ME without saying it, but for cheap scanners like V series this comes at a price, (some extra $50, IIRC). When bundled software is the "Plus" or "Ai" version then it comes included, but you also pay for it. For this reason having or purchasing ME feature closes the gap between V700/850 and high end flatbeds.


    Velvia may deliver +3.6D, so contrast can be 1:4000, this is x4000 more light in the transparent areas than in the shadows. If the sensor delivers (top) 14 bits DR this is some 16000 levels of gray, so this will leave 2 bits to describe detail in the shadows (and a lot of noise), if the adjusted exposure also has to describe higlights... This imposes taking the reading with to separate shots, one with more exposure integration time than the other.


    In the digital chain front end, it is very difficult for the A/D converter delivering those 14 bits in a short conversion time from the pixel photosite integrated voltage. High end cinematography cameras, like Arri Alexa, use DGA: each analog photosite is connected to two different amplifiers working at "different ISO", so this shortcomming is adressed by building an HDR frame from two A/D conversions comming from a single shot.

    For a flatbed electronics, best industrial solution is taking 2 consecutive shots per row, as we do when processing HDR images from multiple shots in PS.


    By using ME a CCD sensor may surpass PMT nominal dynamic range, but drums still have another major advantage, this is being exent of stray light problems.

  6. #26

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    Re: Epson V850: better optics, *really*?

    Quote Originally Posted by sharding View Post
    Epson V850: better optics ? [/B]
    V850 vs V800 lenses difference is coating. A better coating delivers less stray (parasite) light. This may make a difference in the deep shadows of contrasty slides, I see little impact with negatives reaching 2.3D, to say a number.

    Most of the effect can be compensated in post, in the same way PS can make mostly match a shot taken with an uncoated lens to same subject taken with a coated lens. Digital filtration makes wonders.

  7. #27

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    Re: Epson V850: better optics, *really*?

    Pere thanks for the detailed info on the V-series scanners and your expertise in it all. Its' interesting reading, thanks for sharing.

  8. #28

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    Re: Epson V850: better optics, *really*?

    Quote Originally Posted by EdSawyer View Post
    Pere thanks for the detailed info on the V-series scanners and your expertise in it all. Its' interesting reading, thanks for sharing.
    Not at all, thanks for reading it. Sharing allows own knowledge organization, and to find own missconceptions.

    I'd like to point that the more I learn on digital processing the more I appreciate darkroom wet printing. Digital tools are amazing, something to use and love, but IMHO a photographer can also be measured by his ability get a sound print with simple tools, by understanding original light comming from subject, and treating that light with respect.

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