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Thread: DSLR scanning vs Dedicated flatbed scanning.

  1. #81

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    Re: DSLR scanning vs Dedicated flatbed scanning.

    It's very easy to scan 35mm at 2040 ppi native (not downsampled) in an Imacon/ Hasselblad. Let's see if you can figure it out. If you'd operated the scanner even the most minimal amount you'd know how.

    It is otherwise fundamentally clear you know very little about high end scanning or post-production of any sort at any level other than that of a consumer of the finished scan.

    More importantly, was the person who had you scan those transparencies aware that you were not going to be scanning them yourself?

  2. #82

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    Re: DSLR scanning vs Dedicated flatbed scanning.

    Quote Originally Posted by interneg View Post
    It's very easy to scan 35mm at 2040 ppi native (not downsampled) in an Imacon/ Hasselblad.
    Interneg, in a job I had I designed the PCBs and firmware interfacing a linear sensor. Let me explain that you won't know if the image is downlampled in firmaware or not. When interfacing a linear sensor you can do it in two ways:

    1) Pixel binning, you read the averaged analog value of several pixels in the linear sensor row feeding a single voltage for the bin to the amplifier and A/D. Later you digitally average several rows to have square pixels.

    2) You read all sensor resolution and then you digitally "average" rows and columns.

    My guess is that the X5 uses the second way because it has more room to use a refined advanced processing to get a better output, I cannot imagine the X5 designers using the first approach, as the 8k pix sensor they used can be read very fast.

    In the V850 I've doubts, because the sensor has +40,000 pix so it's slower to clock out all voltage readings from the sensor.

    What I say is that while you won't downsample the image (best guess) the X5 has done it in firmware for you, cooking an optimal result.


    While I've never operated an X5, by sitting at operators side I may see things that I guess you have not realized if never have designed and fielded a high end linear sensor camera for demanding industrial applications.




    Quote Originally Posted by interneg View Post
    It is otherwise fundamentally clear you know very little about high end scanning or post-production of any sort at any level other than that of a consumer of the finished scan.
    Again going to personal attack, and not answering the question in post #78

    Please answer the question in post #78, not answered





    Quote Originally Posted by interneg View Post
    More importantly, was the person who had you scan those transparencies aware that you were not going to be scanning them yourself?
    Me, the artist and the X5 owner are very close friends. I do all the edition of his work for free, we share darkroom and the CPE2. My editions of his work (beyond locally) have been exhibited in several countries, some as distant as Finland vs Canada, and at least nobody complained.

    ________

    Attached, the (area) camera config (made last week) of a system I'm designing know, running at 240 FPS under DCAM Format 7, it has 8 cameras per subsystem totalling 32 in the system, cameras work VIS+IR. Using Intel Image Processing Library to speed up processing. System intelligence uses Genetic Algorithms, Neural Networks and Expert System.

    I show that only to point that it would be not easy for you to discredit my technical understanding about we are speaking.
    Attached Thumbnails Attached Thumbnails ___CAM.jpg  

  3. #83

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    Re: DSLR scanning vs Dedicated flatbed scanning.

    The Epsons use folded optics & likely a similar sized sensor to most other CCD flatbeds - the X5 uses a 72mm sensor. Nowhere in their own materials does Epson claim to use anything other than that system.

    Post #78 is a nonsensical question. It is based on a high contrast edge specifically chosen, then oversharpened until horribly noisy. You've chosen the one part of those tests that can be distorted to make the Epson look better. How about showing us the other bits of those images that clearly show the big flaws in the Epson?

    You might know about aspects of electronic design, but it is clear that the critical optical and mechanical relationships that high end scanners rely on are far outwith your knowledge. The way the sensor reads out is rather less important than the lens being held in a precise relationship to the film & sensor with no transmitted vibration to kill sharpness & contrast.

    If what you state is true about your access to an X5, why have you not been allowed to operate it? They are very popular in higher education because they are easy to teach students to operate & hard to truly break.

  4. #84

    Re: DSLR scanning vs Dedicated flatbed scanning.

    Quote Originally Posted by Pere Casals View Post
    Chester, this is flawed side by side.
    > this looks 35mm film, at least the aspect matches exactly 3:2. Here we talk about 4x5", were the X5 loses 75% of the linear performance while the V700 holds the same.
    Your test was cooked to discredit the EPSON, while it's true that the X5 is extraordinary for 35mm it's close to the EPSON for MF, and inferior to the EPSON for LF.

    My example is from my own 5 x 7 inch negative. The imacon is capable of much more precise focus on the film. The Epson, even if you use the plastic holders (which is not an option for 8x10 or 5x7)' or one of the 'betterscanning' holders, or your own wet mount glass sandwich, simply doesn't have the capability to focus on as tight of a plane. (even if you go thru the trouble of shimming your wet mount 'betterscannning' holder with the supplied shims)

    This goes back to Peter's much earlier comment about how comparing numbers with different types of machines doesn't necessarily line up. A 2000 dpi drum scan can easily beat a 7000 dpi epson flatbed. Just like a 12 megapixel Nikon D700 can easily beat a 20 megapixel micro 4/3rds camera.
    Last edited by Chester McCheeserton; 21-Jun-2019 at 16:40. Reason: typo O's

  5. #85

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    Re: DSLR scanning vs Dedicated flatbed scanning.

    Quote Originally Posted by interneg View Post
    The Epsons use folded optics & likely a similar sized sensor to most other CCD flatbeds - the X5 uses a 72mm sensor. Nowhere in their own materials does Epson claim to use anything other than that system
    My own tests and all information you will find around says that V700 resolves 2900dpi in the 5.9" scan width, so it can see 17000 effective separated pixels in the scan width.

    Look, this is a remarkable technical achievement with folded or non folded optics. An X5 will never see more than 8000 pixels in a row, and it actually sees 6900 pix in the scan width, the epson sees 17000 effective.

    If the EPSON lens covered 3" instead 6" then it would sport 6000dpi effective, even for MF. I don't know if you are able to understand that, but's it's pretty straight.

    The V700 has not more resolving power because it scans FOUR 35mm strips in a single pass, plus the holder margins.


    Quote Originally Posted by interneg View Post
    You might know about aspects of electronic design, but it is clear that the critical optical and mechanical relationships that high end scanners rely on are far outwith your knowledge.
    Again a personal attack. Let me explain you that systems I design and field makes non contact metrology, of course of the subpixel kind. I measure very well system accuracy and I know what comes from optics, from frame vibrations and from product motion blur.


    Quote Originally Posted by interneg View Post
    If what you state is true about your access to an X5, why have you not been allowed to operate it? They are very popular in higher education because they are easy to teach students to operate & hard to truly break.
    If the V700 is as crappy as you say, how it is possible that the samples posted by Pali and the ones in the Collaborative tests are corroborating what I point.



    Quote Originally Posted by interneg View Post
    Post #78 is a nonsensical question...
    LOL, interneg, I have you in the point I wanted: negating facts from reliable sources




    interneg, let's be clear:

    X5 yields under 2000 dpi effective for 4x5, a shame for a $16,000 machine. A 8000pix sensor for a 4" width will never yield more than 2000dpi effective, but well under.

    Of course 4x5 was not a priority in the X5 design, they could have used a 16K sensor.

    _____________________________


    The X5 and the V850 are very different machines, "8k sensor with variable magnification" vs "40k sensor with 2 fixed lenses".

    Sweet point of the X5 is 35mm, sweet point of the V850 is 5x7".

    You cannot say that the X5 is a marvel and the V850 is pure crap, and demonstrating this with personal attacks.


    Look, the V850 beats the X5 for 4x5" and up, you should have some respect for a cheap product doing that, in the same way an X5 deserves respect for taking 6900dpi effective from 35mm film.
    Last edited by Pere Casals; 20-Jun-2019 at 07:20.

  6. #86

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    Re: DSLR scanning vs Dedicated flatbed scanning.

    Pere: how about you show us the results from the Imacon 949 (largely same guts as an X5) in that collaborative scanner test alongside the Epson? Specifically the table edge & the cloth detail. It shows quite a serious difference to what you keep telling us, doesn't it?

    And you might also want to consider the results of an actual teardown and MTF test of a V700, which dismantles your assertions about its useable resolution.

  7. #87

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    Re: DSLR scanning vs Dedicated flatbed scanning.

    Quote Originally Posted by interneg View Post
    Pere: how about you show us the results from the Imacon 949 (largely same guts as an X5) in that collaborative scanner test alongside the Epson? Specifically the table edge & the cloth detail. It shows quite a serious difference to what you keep telling us, doesn't it?
    Once the V750 crop is edited with 2 or 3 clicks it's mostly like all the other crops:

    Click image for larger version. 

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    Pro scanners have a very good automatic digital sharpening in firmware or in software, and the delivered image is optimitzed yet to its best, with the EPSON you have to do it on your own later, this is well known, the Petapixel test also explains it.

    If we could see that negative with a microscope probably we are sharpening the image in the negative that may have some blur there.



    The MTF of the X5 for 4x5 at 1900dpi is zero, while the V700 has a Transfer of Modulation until 2900dpi (in the Hor axis).

    Please see this Pali V700 test: https://www.largeformatphotography.i...=1#post1478033

    Elements 5.6 and 5.4 were resolved, which is 2900x2300 effective.

    https://www.largeformatphotography.i...=1#post1477892

    Remember that the X5 for 4x5 only resolves Elements 5.1 or 5.2. Test you'll hassie and you'll find that.

  8. #88

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    Re: DSLR scanning vs Dedicated flatbed scanning.

    Quote Originally Posted by Pere Casals View Post
    Once the V750 crop is edited with 2 or 3 clicks it's mostly like all the other crops:

    Click image for larger version. 

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    Pro scanners have a very good automatic digital sharpening in firmware or in software, and the delivered image is optimitzed yet to its best, with the EPSON you have to do it on your own later, this is well known, the Petapixel test also explains it.
    No. Wrong. It's because professional scanners don't give severely misleading data about their sensors. They are straightforward 3-line CCD - often available on the open market from Mouser etc - not a 6-line attempting to claim better resolution & their useful resolution limits are by design or mechanical precision limitations. The teardown covers why the Epson sensor design has severe limits in useful resolution before going blurry. And because of its design it gets really noisy when sharpened & the double line interpolation design does really odd things to the grain.

    That's a horrid, noisy thing you posted there, and the fine details are still wooly. It would be really obvious in a print. I know because it looks like every other Epson scan that people try to pass off as being 'good' in some way.

    That you didn't show a side-by-side with the 949's non sharpened results is very telling.
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    When you have that much more detail & less noise, sharpening has a better effect if you wish to add it.

  9. #89

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    Re: DSLR scanning vs Dedicated flatbed scanning.

    Interneg, I don't understand why you are such a hater of the Epsons

    Let's go point by point:


    Quote Originally Posted by interneg View Post
    No. Wrong. It's because professional scanners don't have misleading data about their sensors. They are 3-line CCD, not a 6-line attempting to claim better resolution.
    > The 6-Line sensors are a great improvement over the 3-Line ones, the second RGB row covers the gap between the microlenses of the first row, this is the perfection. This is basic knowledge. Epson literature shows they are proud of the 6-Lines.

    > Anyway if you consider only the first 3 Lines of the EPSON still it has +20,000Pix rgb, 2.5x what the X5 has.

    > You should understand that the High Res lens of the EPSON covers 5.9", this is a lot, this is the weak point of the EPSON for 35mm, while the hassie covers 1" !!!

    > As format is larger the X5 loses its advantage, by 4x5 the Epson resolves element 5.6 (Hor), the X5 resolves the 5.2. By 5x7 the X5 only resolves the 5.1 (or 4.6) while the Epson still holds the 5.6, as it's a fixed lens the Epson always resolves 5.6 from 35mm to 5x7. The X5 lowers resolution as it zooms out, from 6900 dpi at 35mm to 1500 at 5x7".

    > And the Epson also makes 8x10 , here we cannot compare, but the Epson delivers around +2000dpi effective for 8x10 while the X5 with the 5x7 adapter only performs 1500.



    Quote Originally Posted by interneg View Post
    That's a horrid, noisy thing you posted there, and the fine details are still wooly. It would be really obvious in a print. I know because it looks like every other Epson scan that people try to pass off as being 'good' in some way.


    The dB SNR vs D of the V700 is sound, it shows pretty right at 3.1D. Add the multiexposure effect that's not included in this graph, IIRC. With multi-exposure you have around the 3.1D reading of the table for 3.4D.



    This test was made by Pali, with the V700 sharpened by me in two clicks, honestly, do you thing that result from high end flatbeds are better ?
    To me, same noise, same sharpness, if edited also all scanners the same colors:


    Last edited by Pere Casals; 22-Jun-2019 at 02:29.

  10. #90

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    Re: DSLR scanning vs Dedicated flatbed scanning.

    I'd add that another source of performance for the V850 is the fixed magnification of the lens, so the lens is optimized for that exact fixed magnification which is around 1:3 for the HR lens

    Instead the X5 has to magnify 2:1 to 1:2.5, which is a 5 times change, so I guess they use the 1x version of the Rodagon D, which is in the center of the range.

    The lens in the X5 has a retail price that's higher than a whole V850, I know very well those Linos Rodagon D, I've used them for machine vision projects, very fine glass, no doubt, but they are sold in the 1x and 2x versions, each optimized for a particular magnification. Of course, lenses at 1x or 2x miss the optimal performance when you move from the optimal magnification.


    In the case of the V850 they take crazy 5.9" with the lens, which is an insane amount to scan 35mm and even MF, still the optics perform better than expected just because the lens works at the magnification at what it was optimized.

    Some in this forum had been saying that the V700-850 had cheap plastic lenses inside. Not true... resolving those 2900 dpi (Hor) in a 5.9" field is not that easy, those 17000 total effective pixels at extition for the covered field is a remarkable number.

    So, IMHO, every machine has weak and strong points, and a cost.
    Last edited by Pere Casals; 22-Jun-2019 at 10:43.

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