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Thread: DSLR Scanner: Camera Supports and Positioning

  1. #71

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    Re: DSLR Scanner: Camera Supports and Positioning

    Yes that is true, I was thinking of easily obtainable things one could put on a BOM. Old electric shutters are very different from one to the other in terms of voltage and mounting diameter and opening diamater. But of course it would be best using a camerashutter. Maybe just use a repair part shutter of a popular DSLR, that will be in stock for many years to come. Yesterday I was in a hardware store buying paint and flooring stuff and saw a proxxon kt 70 compound table on a shelf. I tried it out a bit and its a very nice unit! If I get around to making a mediumformat scanner(I dont shoot much LF) I will probably use this.

  2. #72
    Peter De Smidt's Avatar
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    Re: DSLR Scanner: Camera Supports and Positioning

    The Proxxon does look nice. If only it had more than 1-3/16" y-axis travel, it would be a very viable approach
    “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

  3. #73

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    Re: DSLR Scanner: Camera Supports and Positioning

    Well there is also the kt150, it has 150mm X 150mm travel and is probably even better. For a 4x5 you dont really need more than 110mm on a fullframe sensor.

    Its a bit more expensive but still quite reasonable

    http://www.amazon.co.uk/Proxxon-Cros.../dp/B000S6DU94

    You get all sorts of retrofits for steppers to.
    http://www.damencnc.com/en/machines/retrofit-kits/180

    or diy

    http://www.youtube.com/watch?v=7IQz9wOCt7k

  4. #74

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    Re: DSLR Scanner: Camera Supports and Positioning

    Now I'm getting horny...

  5. #75

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    Re: DSLR Scanner: Camera Supports and Positioning

    Read up on the k150, its not as nice as the k70 it seems. The nut and screw is of less precision, ie more backlash. This will not be a problem for us though since we have zero load. Its very easy to compensate for backlash since it is constant, well its constant between the 10 or so movements we make. After time and wear it probably will change a tiny bit, and the programming needs a bit of tuning. At least if zero transformation during stitching is the goal. Its also possible to get a really tight delrin nut. That nut will almost not wear at all and can be made a lot tighter so backlash is almost completely gone. Not sure if that is necessary though. Also the is a zillion compound tables out there best to find one in a shop so one can have a feel.

  6. #76
    Peter De Smidt's Avatar
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    Re: DSLR Scanner: Camera Supports and Positioning

    One issue with the milling table idea is that it quickly comes close to the cost of something like the Microcarve MV3, http://www.microcarve.com/mcMV1.htm , which has much bigger area of movement, as well as an automated Z-stage for photo stacking. Moreover, both approaches would require a very thin light source. This doesn't mean that either approach is a bad one, but there are still some challenges.
    “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. #77
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    Re: DSLR Scanner: Camera Supports and Positioning

    At 1:1, is there any point to reversing a lens?

    I can see at the macro range how reversing would help, but I don't see what difference it makes at 1:1.
    Science is what we understand well enough to explain to a computer. Art is everything else we do.
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  8. #78
    Peter De Smidt's Avatar
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    Re: DSLR Scanner: Camera Supports and Positioning

    Quote Originally Posted by BetterSense View Post
    At 1:1, is there any point to reversing a lens?

    I can see at the macro range how reversing would help, but I don't see what difference it makes at 1:1.
    It all depends on the lens.

    With the F-mount, for instance, the distance from the back of the lens to the sensor is approximately 40mm. In the forward position, Nikon's micro lenses are optimized for greater subject lens distances, and so using the lens reversed, in theory, leads to better performance, where the subject to lens distance is about 40mm. I haven't empirically confirmed this yet with my lens, though.

    If you look at something like the 2x Rodagon d, Rodesnstock says that it works best forward at 1:2 and better reversed at 2:1. With my initial test at 1:1, it worked significantly better reversed.

    If the lens is perfectly symmetrical, then the orientation shouldn't matter.
    “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

  9. #79

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    Re: DSLR Scanner: Camera Supports and Positioning

    About the Microcarve, I think that is a great solution to our problem. It quite cheap, has all axes of movement/adjustment and best of all, its all thought out. If one can find a good flat lightsource this type of design would work very well. If we need a deeper lightsource then the milling table is no problem since we can just put the camera higher. Also If one build a gantry style machine lke the Microcarve from scratch one can just have a higher gantry. Since we abbly no x or y load it doesn´t need to be very strong only vibration free. Also very small motors, drivers and powersources can be used since there is no load Speaking of wich how did the motroshield turn out?

    This is a cheap and small opensource project that leaves the bottom open. http://www.shapeoko.com/

  10. #80
    Peter De Smidt's Avatar
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    Re: DSLR Scanner: Camera Supports and Positioning

    I spent a lot of time investigating CNC rigs, and the Microcarve is the best combination of features, quality and price that I could find. In addition, John has been very responsive to inquiries.

    The pluses of a Microcarve, or similar, for our purposes are:
    1) It is inexpensive for the level of quality involved. When you add up the costs of a diy version using linear bearing rods, x-y milling tables... you quickly approach the cost of a Microcarve.
    2) It has a fairly large range of motion.
    3) It can be dismantled/rebuilt without damaging anything. This also means that it should be easy to modify.
    4) A computer controlled Z-axis would make it easy to focus stack. This could help with our limited depth-of-field, especially with curly film.
    5) If one gets tired of dslr scanning, you'd still have a very capable cnc machine.

    The negatives are:
    6) Cost. With motors, drivers, power supplies...the cost will approach $1000, not including a light source. While that's not an unreasonable amount for such a capable positioning system, it's too much money for me to commit to a project that I don't really need. I've already spent over $500 on this project.
    7) Limited space for a light source.
    8) Z-axis is ideal for CNC, but a finer pitch would be better for a scanner. The main reason is that a finer lead screw will not move with the weight of the camera. With the standard one, you have to use the holding power of the energized stepper motor to keep the camera's z-axis height steady. I'm not sure of there's any vibration when the motor's are energized.

    A few more points: the standard Microcarve comes with a 4" z-axis. John can make a 6", or possibly longer axis, if needed. The MDF platen could possibly be made out of a thick acrylic sheet, which could help with that light source issue. The design could be changed so that the x-axis lead screw would be moved to the side of the platen, allowing more space for a light source. Additionally, one could built a stand to raise the microcarve up, and also replace the end panels for the x-axis, such that there's more space between the drive lead screw and the platen. This would also give more space for a light source. Finally, one could make new MDF sides that raise the gantry up higher.
    “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

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