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  1. #1
    Barry Kirsten's Avatar
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    LF Pinhole - design and building

    Hoping to get some interest in this aspect of photography, and following the demise of that excellent site f295, I thought Iíd set the ball rolling by describing in more detail how I went about building a camera which I recently mentioned here: http://www.largeformatphotography.in...amera!/page324

    A friend on this forum happened to throw in a box of 5x12 x-ray film in a parts swap we did and that got me thinking about a panoramic pinhole camera in this format. The result here followed months of trial and error:

    Click image for larger version. 

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    The camera has front rise and fall of +/- 15mm to allow it to be used level and yet ensuring that the horizon remains straight, since the horizon will be curved in a curved film-plane camera if it is tilted up or down. As it turned out I could only find 15mm as Iíd made the frame for the front too wide top and bottom. I havenít yet tested whether this is enough. The camera has a bubble level in the top and sighting dots made from 1Ē painted nails to aid composition.

    Click image for larger version. 

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    The first hurdle to overcome was bending the plywood back. This was eventually achieved by scoring the inside surface with vertical Vs spaced at 1cm intervals using a router, then soaking and careful progressive bending over several days, using clamps and weights, then eventually gluing top and bottom to hold it all together. It was a hair-raising experience and I felt several times that I came very close to splitting the wood. In retrospect, Vs at 5mm spacing may have made the bending easier.

    Click image for larger version. 

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    I used a 0.5mm EMS (electron microscope) aperture for the pinhole. These are truly excellent - laser drilled precision. Iíve used them before on other cameras with great success. Iíd never think of making my own now. Theyíre available from a guy on f295 at $1 apiece posted. If anyone has contact with Earl, would you mind seeing if heís interested in posting here?

    Mounting these pinholes is tricky, since theyíre very small. Some folk use tape with a 1.5mm hole punched in it to grab the pinhole; the pinhole is then taped to the camera front. I donít yet have a punch to allow me to do it this way, but Iíve ordered a couple from China. Meantime I mount my pinholes in a small brass washer, using a couple of blobs of black paint that find their way by capillary action. The pinhole on its washer is then mounted into a recess drilled into the plate (more black paint).

    As per my previous post (above) I found vignetting on my first test shot, which I immediately thought was an image circle issue. I thought that I may have to mount the pinhole further forward to fix this. However a member (NedL) was right when he suggested that it was obstruction. Sure enough, although Iíd beveled the exit hole in the rear of the plate, there was still a definite ridge, which Iím sure was responsible. Iíve since ground this down, but have not yet tested it as I have a scratching issue with my developing trays and have to get some glass cut to remedy this. The next pic shows the rear of the plate and also a view of the front showing the clearance needed for rise/fall and horizontal field.

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    The 0.5mm pinhole is mounted 135mm from the film plane. I had intended it to be 127mm (5Ē), the radius of the film curve, but things donít always turn out as hoped. Fortunately pinhole is very forgiving, and I donít think any unevenness in exposure will show up. At 135mm the speed is f/270. The one test Iíve done suggests that the image is a little soft. Iíll do a few more tests after I sort out my developing issues, and may yet go down to 0.4mm and f/340.

    A note on bits and pieces: I now get everything from China via eBay. No doubt about it. Over the years Iíve scoured the country from engineering suppliers to model shops and found sourcing small screws and knobs etc, the type of things so vital to DIY photography, next to impossible. For me eBay is the answer, and knowing how to search is very helpful. Terms like M3 screws for 3mm metric, or knurled knobs, case clips etc usually turn up direct hits or lead to further search clues. The two brass pieces in the last two pics are known in eBay speak as "M3 / M4 Brass Knurled Nuts Insert Embedded Nuts"; I used these as nuts to secure the front panel and as embedded nuts held with epoxy for the front panel to bolt into.

    So how about it LF Pinholers? I'm sure there would be much interest in your own pinhole camera building achievements. There is certainly interest in pinhole photography here, as evidenced by the many favourable responses to pinhole images posted here. Love to hear from you.

  2. #2
    Randy's Avatar
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    Re: LF Pinhole - design and building

    Barry, that is quite a bit of workmanship. Thanks for the detailed description. I am afraid the extent of my pinhole camera construction is making a lens-board pinhole for my 8X10, 5X7, and 4X5 cameras.
    https://dl.dropboxusercontent.com/u/52893762/bigger4b.jpg

  3. #3

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    Re: LF Pinhole - design and building

    Hi Barry

    Good idea and thanks for taking the initiative. I'm just starting to explore pinholes so this will help me a lot. Congratulations on your camera by the way - very nice.

    Regards
    Dave

  4. #4
    Tin Can's Avatar
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    Re: LF Pinhole - design and building

    Wacky camera, first try

    Looks like light leaks, shot on 11X14" 2 side-X-Ray 250mm Zone Plate Actual image size 11x11"

    20 seconds f180 hole. 14" extension, Packard shutter

    Copied with cell phone on LED Pad

    Wacky Camera by TIN CAN COLLEGE, on Flickr

    11X11 X-Ray 250mm Zone Plate by TIN CAN COLLEGE, on Flickr
    2022

  5. #5

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    Re: LF Pinhole - design and building

    I like the Spampod.
    Ron McElroy
    Memphis

  6. #6
    Tin Can's Avatar
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    Re: LF Pinhole - design and building

    I don't eat Spam, but will when the time comes

    However I just installed 3/8" floor flange and a bit of pipe for third leg

    Waiting on 0.8mm pinhole to test again

    Mr Pinhole told me so

    Quote Originally Posted by Ron McElroy View Post
    I like the Spampod.
    2022

  7. #7

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    Re: LF Pinhole - design and building

    The quality of so many of these home built projects puts me to shame. I think I linked to my cigar box camera before, but the details are here: http://grahamp.dotinthelandscape.org/pinhole.html
    Much cruder in construction, though I have done some decent work with it: http://grahamp.dotinthelandscape.org/pinholeday.html.

  8. #8
    Tin Can's Avatar
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    Re: LF Pinhole - design and building

    After sleeping on it, I think a lot of my problems with Wacky Camera are internal reflections

    It is made of aluminum sheet metal, painted black long ago

    I am going to buy Scope Flocking to put inside http://www.scopestuff.com/ss_flok.htm

    I also will try different Zone Plates and Pinholes
    2022

  9. #9

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    Re: LF Pinhole - design and building

    Quote Originally Posted by Tin Can View Post
    After sleeping on it, I think a lot of my problems with Wacky Camera are internal reflections

    It is made of aluminum sheet metal, painted black long ago

    I am going to buy Scope Flocking to put inside http://www.scopestuff.com/ss_flok.htm

    I also will try different Zone Plates and Pinholes
    Why would internal reflections only be in a single direction?

    Is the direction the line marks are the same as the movement of the darkslide? I mean could it be you have leakage when pulling the darkslide. That each line is the edge of the darkslide.
    Expert in non-working solutions.

  10. #10
    Tin Can's Avatar
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    Re: LF Pinhole - design and building

    The bottom inside surface is really shiny...

    I never completely removed the DS as 3" of the DS slot side of film is never exposed and both sheets processed totally clear in that area.

    So I think the light traps are sealing the DS, and IDK...




    Quote Originally Posted by Havoc View Post
    Why would internal reflections only be in a single direction?

    Is the direction the line marks are the same as the movement of the darkslide? I mean could it be you have leakage when pulling the darkslide. That each line is the edge of the darkslide.
    2022

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