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Thread: Making a scanner with a DSLR

  1. #451
    Peter De Smidt's Avatar
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    Re: Making a scanner with a DSLR

    Daniel Moore did a stitch with PTgui for me. Thanks! It was 17 frames covering a 6x7cm negative.



    The resulting file will make just under a 16x20" print at 300 dpi.

    Apparently my calculations were a bit off. It looks like only 6 frames are needed with my Nikon 55m micro at an indicated 1:1.
    “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

  2. #452

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    Re: Making a scanner with a DSLR

    To me, this looks good Peter! A bit low on contrast? From this image, I don't see any artifacts. Are you going to try a larger negative?

  3. #453

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    Re: Making a scanner with a DSLR

    Looks great! Low-contrast is good, that's what we want (more information). You can always tweak contrast later.

  4. #454
    Peter De Smidt's Avatar
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    Re: Making a scanner with a DSLR

    The image presented isn't very good, and it certainly isn't edited extensively. I thought it would be good, though, to see how the stitching handled the lines and concrete surface. With Daniel's help, it doesn't look like this is a problem.

    There are a bunch of tweaks that can be made. In the first place, I'd like a slightly bigger light source. More importantly, though, it'll probably be very important to mask the lens very well, as contrast will suffer with extraneous light. I'll also build a negative carrier that has a cutout on top of the negative. Once those things are done, I'll start comparing the lenses I have. It looks like that for 35mm and medium format 2:1 might be better than 1:1, but only time will tell. Eventually, I'll get to trying bigger negatives, but at the moment that only leads to more work with little gain. Comparison with other scanners wouldn't make much sense until the system is fully tweaked out.
    “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

  5. #455
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    Re: Making a scanner with a DSLR

    Miracles sometimes occur, and I found myself this weekend with some time on my hands.

    So, I've made much progress on my prototype.

    The first picture (sorry for the iPhone pics of limited quality) shows the general arrangement--horizontal with the camera on a precision slide and the negative held vertically.

    I have built two camera mountings (the second and third pictures), because the parts were available and each will provide a different feature. One is built with a Manfrotto hex-clamp, and the other with a Wimberley Arca-style clamp.

    Both the slides came in a lot of laboratory equipment that I bought. The black one (second picture) is a typical adjustable dovetail slide. The nuts on the side are jam nuts for the adjusters, so this can be made to be tight with zero play. The slide had a riser machined into it, which provides a bit more elevated camera position. With the hex-plate clamp, I can use this one for cameras that don't have Arca plates or for when I'm lashing something up and don't have the right plate.

    The camera is clamped to this stand right now--I am still awaiting a long enough Arca slide to allow me to lock down both standards of the bellows to the Arca slide. That will greatly improve the alignment and rigidity of the bellows. The bellows is made for the Pentacon Six, and I have a short extension tube plus a P6-EF adapter between it and the Canon 5D. The lens is an EL-Nikkor 105/5.6 mounted in a body cap and clamped into the front of the bellows. I will be improving that arrangement, but I'm still awaiting parts. The bellows are adjusted for 1:1 with that lens in this picture.

    The bright aluminum slide is a Velmex 2500--very high quality. It's shown in the third picture. This one also provides a zero clearance in addition to no backlash on the focuser. I constructed an adapter to mount the Wimberley clamp using a 3/4" square tube. With this arrangement, everything is held with at least two fasteners, and there are no rubber pads--all surfaces are machined flat metal surfaces.

    I mounted both slides on aluminum spacers to get the adjusters above the deck, and then mounted a couple of spare Sinar boards to those spacers. No actual Sinar board was harmed in this activity--these are cheapie Chinese knockoffs that I have since replaced with Sinar or Horseman-branded boards. I went to some care to make sure the boards are axially aligned with the slides, and I believe they are within 0.0005" over their length. (I have a machinist's square which has a rated accuracy of 0.000063", but I'm not exactly sure I believe it. I know I can't test it myself to that degree of precision.)

    When I mount these on the horizontal bed, I will allow the Sinarish boards to slide between two aluminum angles used as a track. I will also mount an angle on the edge of the Sinar board to kiss those tracks. That way, I can slide the whole thing fore and aft to provide gross focus and then clamp the two angles together to fix the position.

    The camera mounts really benefit from the horizontal arrangement I'm using. All the forces are applied across flat interfaces--very little is in bending. But that made the negative stage more difficult.

    The negative stage uses an Omega D2 4x5 negative holder, which is two aluminum plates that sandwich the negative. One of the plates is attached to two IKO linear way slides, each of which runs on a vertical track on either side of the negative opening. These slides use a row of ball bearings that run in grooves in the track, and despite their small size, they are very precise. The track is machined hardened steel, and it's so hard that a hacksaw couldn't even scratch it. I had to cut the 20" section in half using an abrasive wheel on a Dremel tool. These slides have zero play. I fastened them to right-angle brackets that have machined surfaces used for clamp-ups for precision wood-working. They are machined to a right-angle accuracy of 0.002" over their length--but in practice they are a bit better than that (checked with that fancy machinist's square). Those two brackets are attached to slides on a crossing track for horizontal movement. Everything is true within a thousandth--but until I fasten down that side-to-side track, I won't know how stiff it all is. The holes are spaced on 20mm centers, and I'll put a screw in every hole.

    The vertical negative will be sandwiched in the negative carrier, and being vertical, I hope there will be no tendency to sag. I am not using glass. No need to worry about fluid mountings, Newton rings, or extra layers of dust. Hopefully, I also won't need to worry about film flatness, but we shall see. Any Omega carrier can be clipped to this one, and the sandwich is held together with clips.

    Note that the negative stage is at the bottom of its travel in the first picture, and at the top in the last picture.

    All of this will be fastened down to a piece of phenolic-coated plywood that is made for tool decks, and that will be clamped to a slab of granite from a sink cutout. I will attached measuring strips to all the movements, and use spring clips to hold the negative stage in place at each position. That's the next step.

    Rick "relieved to see some good stitches from Peter" Denney
    Attached Thumbnails Attached Thumbnails stitch_scanner_1.jpg   stich_scanner_2.jpg   stich_scanner_3.jpg   stitch_scanner_4.jpg  

  6. #456
    Peter De Smidt's Avatar
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    Re: Making a scanner with a DSLR

    Looking good, Rick!
    “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

  7. #457

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    Re: Making a scanner with a DSLR

    Quote Originally Posted by Cesar Barreto View Post
    Rick did actually resumed pretty well the whole scene, but I would like to remember to those who already have Sinar P or equivalent 8x10 cameras and don't mind to make the scanning with hands, instead of machines, that X and Y movements works very fine with these cameras and both planes are naturally aligned.

    A mask for holding 4x5' or 5x7' negatives set on the first frame and a nice SLR digital camera installed in the back and that's it. Of course some variations are possible and I made my scans using a Kaiser column for up and down movement and the Sinar for lateral shift, since at this time I just had a 4x5' camera. Aligning was a PITA, as you say, but after some trials it was easy to go along and make a bunch of scans each day.
    If we are looking at doing the scanning in batches, and not for a dedicated unit, why isn't this the way to go? If it is, what is the cheapest camera I could buy that would work? I would love to be able to scan 4x5's in this way, if better quality than a Epson 700.

    --Darin

  8. #458

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    Re: Making a scanner with a DSLR

    A D5100 would make an excellent and modestly priced capture device.

  9. #459
    Peter De Smidt's Avatar
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    Re: Making a scanner with a DSLR

    Quote Originally Posted by Darin Boville View Post
    If we are looking at doing the scanning in batches, and not for a dedicated unit, why isn't this the way to go? If it is, what is the cheapest camera I could buy that would work? I would love to be able to scan 4x5's in this way, if better quality than a Epson 700.

    --Darin
    The challenges with a view camera are:
    1. Having enough shift and rise to cover the negative.
    2. The difficulty in aligning everything.
    3. Sturdiness.

    Cesar talked about using an 8x10 Sinar P (or similar). If you have one, and feel like giving it a try, then by all means do so. I've owned a couple of Sinar Ps, including and 8x10, and they are great cameras. My impression based on that experience is that they would be a PITA to use for this purpose. It's not something I'm going to pursue.
    “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

  10. #460

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    Re: Making a scanner with a DSLR

    Following the comments by Darrin and Peter, I'd say that using a Sinar or similar camera really can be time consuming but when I suggested 8x10' models I was considering bigger shift and rise movements.
    And I always had some faith on Sinar cameras regarding alignment and sturdiness, so if one takes the obvious care, like mirror locking and so on, I don't see much to worry about.

    I'm actually looking for an adapter wich allows to use a small camera right on the top of Sinar stand and I already missed three on the auction site. This way I could use a Nikon camera with it's own lens, but maybe one could make an adapter to fix the body to a lens board and so having the Sinar set with 3 stands: camera, lens and film.

    One of the advantages of this solution is avoiding the use of glass, since the film is easily held flat when vertical, leading to less spoting and flare.

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