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Thread: DSLR Scanning - Signal / Noise

  1. #21

    Re: DSLR Scanning - Signal / Noise

    Quote Originally Posted by interneg View Post
    Anyone who spends their time quoting 1951 resolution charts while dismissing MTF and information capacity has clearly had no useful engagement with the peer reviewed literature of imaging science since about 1952. The 1951 chart is popular because it provides simplistic answers for camera fondling amateurs suffering from sub-Freudian pathologies with no apparent understanding of where real world imagemaking places demands on imaging systems.

    The D200 sensor has better MTF than the Epson scan array, lower noise, & is designed to be able to take sharpening well - to the point that the Nikon delivers sharpness performance more in line with its sensor resolution, while the Epson gets rapidly bogged down beyond about 7-8mp for a 4x5.
    He's trolling. Don't feed him.

  2. #22

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    Re: DSLR Scanning - Signal / Noise

    Quote Originally Posted by sperdynamite View Post
    He's trolling. Don't feed him.
    only telling the truth, and countering missleading information, this is the truth: https://www.largeformatphotography.i...=1#post1479178




    Quote Originally Posted by interneg View Post
    Anyone who spends their time quoting 1951 resolution charts while dismissing MTF and information capacity has clearly had no useful engagement with the peer reviewed literature of imaging science since about 1952. The 1951 chart is popular because it provides simplistic answers for camera fondling amateurs suffering from sub-Freudian pathologies with no apparent understanding of where real world imagemaking places demands on imaging systems.

    The D200 sensor has better MTF than the Epson scan array, lower noise, & is designed to be able to take sharpening well - to the point that the Nikon delivers sharpness performance more in line with its sensor resolution, while the Epson gets rapidly bogged down beyond about 7-8mp for a 4x5.
    All that you say is missleading and false, the reality is this one: https://www.largeformatphotography.i...=1#post1479178

    This is the reality, the truth, the fact.

    If you cannot get perfect LF scans with the V700 it's your fault, the machine is perfectly able, the results in that test are the truth, real facts.

    Pali was able to match performance and color of the V700 with the drum even at pixel peeping level, me I'm also able. You are not.


    PD: the information you have about V700 MTF is totally wrong. The 35mm holder takes 4 strips, place something opaque under the 3 unused strips and you are to remove 95% of the flare, resulting a perfect MTF like the one you have in the X1.
    Last edited by Pere Casals; 14-May-2020 at 17:31. Reason: PD:

  3. #23

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    Re: DSLR Scanning - Signal / Noise

    Quote Originally Posted by Blackmarxz View Post
    Hello,

    How many images can i stitch from a 4x5 negative - before signal/noise ratio drops significantly?

    The more images you stitch the better, but with the A7R4 in particular you would have to stitch 3 overlaved horizontal images in a column, taken with the sheet vertical to take most of the resolving power a 4x5 sheet may usually resolve.

    An ultra sharp 4x5 sheet may slightly improve if stitching a 2x2 or a 3x3 mosaic, a 4x4 mosaic would be usually a plain overkill (with the R4) if your lens is really. A bad lens requires more crops for the same.

    If you are interested in performance measurement just buy a usaf 1951 glass slide: https://www.ebay.com/itm/1951-USAF-G...cAAOxymiVRAhWE

    This will tell you what lens at what aperture works the best, if you have DOF / alignment / focus issues and what real improvement adds pixel shifting. Many times the lens itself would be the limiting factor, pixel shift is not to add much when the lens itself is the limitation, you won't find a commercial lens resolving 240MPix over 35x24mm sensor, by very far, and instead you may have several factors degradating the glass work.

    So, let me advice to purchase that glass slide that it will help you to quantitatively refine your scanning. It will tell you what it's worth and what it isn't and when: The perfect tool to overcome urban legends around about glass, etc.


    Quote Originally Posted by Blackmarxz View Post

    Subject to DOF restrictions would seem I can do a fair amount, however expect at some point the DSLR images dont get any better at picking up details

    DSLR scanning requires accurate alignment and focusing, also a lens that has a very flat focus field may help when crop is small.

    An excellent setup for that is using a reversed enlarger lens, with the lens reversed and close to the film your focusing should be easier, but a regular lens may work easier with the camera.


    If you have to buy a decent stand and a good illumination source, or to inverst in an expensive DLSR then an old/used V700 would be better, because it takes most of the Image Quality the sheet has without having to stitch crops and without the many DSLR complications. Also the V700 has an infrared channel to detect dust and scratches, this is specially useful for color film and it would save a large amount of time in the edition, with perfect results. Manually removing dust in Ps will never deliver a perfect result and it's an extremly nasty job when a sheet has that problem. Also the V700 sports a very good color conversion. Epson is a world class company in color management, for example they have leading position in Pro inkjet printing, so they sport a very proficient color managent from scratch that otherwise it would be not that easy to reach by other means.


    Anyway an stitched DSLR can deliver amazing image quality, I checked that personally: https://www.largeformatphotography.i...e-DSLR-scanner , obtaining best results with a reversed enlarger lens, now I've a new USAF 1951 slide reaching Group 9 and I can tell you that with DSLR scanning you may obtain more resolving power than you may want, still I would recommend you not using DSLR scanning for LF to avoid stitching and other nightmares.

    DSLR scanning is very good for 35mm and quite good for MF if having a very expensive last model DSLR, but for LF you have to stitch crops to get a sound perfomance, and a lot of crops if your DSLR is not a very expensive one.

  4. #24

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    Re: DSLR Scanning - Signal / Noise

    Quote Originally Posted by sperdynamite View Post
    He's trolling. Don't feed him.
    I know, I know - especially when it's very obvious that a lot of bricks are being thrown from inside a glass house.

  5. #25
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    Re: DSLR Scanning - Signal / Noise

    I've reached my limit. I've blocked a number of people, but that doesn't really work. I'm going to stop checking in here, at least for awhile.
    “You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
    ― Alexander Den Heijer, Nothing You Don't Already Know

  6. #26

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    Re: DSLR Scanning - Signal / Noise

    Quote Originally Posted by Peter De Smidt View Post
    I've reached my limit. I've blocked a number of people, but that doesn't really work. I'm going to stop checking in here, at least for awhile.
    I have you blocked since years ago, but anyway I click "View Post" when I feel it contains plain missleading and false information or an slander. This time it was the case.


    See this: https://www.largeformatphotography.i...=1#post1505192

    Your lies, slanders and personal attacks come from far. I removed from my ignore list several times but no more, so you reached my limit long time ago.

    Anyway, when you throw missleading information or an slander then I may tell the truth.

  7. #27

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    Re: DSLR Scanning - Signal / Noise

    For reference material look here:

    https://www.largeformatphotography.i...=1#post1479178

    There you have a well made side by side of 2 Creo machines, a Scanmate 11000 drum and a V700.

    This is a test made with a proficience level you only can dream with, you don't have that level, sorry. So it's ridiculous you try to discredit that evidence.

    Epson flatbeds have been attacked with false information by people having commercial interests: selling problematic pre-press obsolete gear... wanting to sell expensive scanning services not better than the Epson ones...

    The truth: the V700 is a very, very good scanner for LF, rivaling in results with top notch gear in most of the practical situations, as that exhaustive test shows: not more, not less.


    Lachlan, here you have it, learn something: https://www.largeformatphotography.i...-Drum-Scanners

  8. #28

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    Re: DSLR Scanning - Signal / Noise


    LOL, Lachlan is that discrediting the "Scanner Comparison 2019" ???

    Look, this is a MF Fisheye shot, with the lens just nearly touching the hub of the propeller (twin-engine plane), see how small are the large propeller blades seen compared to the hub. Nothing is in focus, man... only the tip of the rotor hub is slightly focused.



    Click image for larger version. 

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    https://www.flickr.com/photos/125592...posted-public/

  9. #29

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    Re: DSLR Scanning - Signal / Noise

    Pere - your image is actually a better actual test of a scanner's MTF than Pali's (which is a better test of colour rendering than the optical performance of scanners). It has large areas of mid-tones where the granularity of the film should be crisply visible at the approx 2400ppi resolution you claim, if the MTF performance wasn't as bad as the Epson's is. It clearly shows that the Epson is incapable of accurately rendering a fair representation of the negative's granularity at anything even vaguely approaching 2400ppi, let alone 1200-1500ppi. There should be sharp apparent granularity, not blurry weirdness.

  10. #30

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    Re: DSLR Scanning - Signal / Noise

    Quote Originally Posted by interneg View Post
    Pere - your image is actually a better actual test of a scanner's MTF than Pali's (which is a better test of colour rendering than the optical performance of scanners). It has large areas of mid-tones where the granularity of the film should be crisply visible at the approx 2400ppi resolution you claim, if the MTF performance wasn't as bad as the Epson's is. It clearly shows that the Epson is incapable of accurately rendering a fair representation of the negative's granularity at anything even vaguely approaching 2400ppi, let alone 1200-1500ppi. There should be sharp apparent granularity, not blurry weirdness.
    That "The Nose" scan was made at 2400dpi hardware with effective performance at around 1800-2000, it is an image for internet, I did not waste any effort in it. To get those 2900 dpi effective HOR with the Epson you scan 6400 hardware and later you sharpen (avoiding overshot) and downzise with bicubic "ideal for reductions".

    Hasselblad X1 won't show any good grain, for LF: for 4x5 it resolves only 1800dpi effective in the horixontal axis and 1600 dpi effective in the vertical axis, when the Epson resolves 2900 dpi effective in the Hor and 2300 in the Vert axis, way more than the X1 for 4x5".

    Look, the "Scanner Comparison 2019" shows that the Epson is an very good scanner that takes most of what a LF negative may have. It is true that the Epson does not depict a coarse grain, but you may be aware that in LF you don't see much the grain, in special if it's tabular (epitaxial D100 in The Nose).

    I guess that you are not proficient with the Epson... but if you want I challenge you: Make a 4x5" scan with your hasselblad X1 (if you have it operative) and send me the negative, I'll scan it with the V850: I'll show you an slightly better scan.


    Don't speak more, send me that negative, take the challenge.

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