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  1. #11
    ced
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    See the link below and maybe jon.oman still has the plans of his very nice 8x10 shown at the link.

    http://www.apug.org/forums/forum62/9...hole-test.html

  2. #12
    Rick A's Avatar
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    I'd go 8x10 and find a couple of cheap film holders. You can use printing paper, direct positive paper, or X-ray film, which is relatively cheap.
    Rick A
    Argentum aevum

  3. #13

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    You can make sharp prints from paper negatives. I suppose they may not be quite as sharp as a film negative, but it won't degrade a pinhole image significantly.
    Note that when you make a print from a paper neg, you place the neg emulsion side to emulsion side with the print. The light is diffused some through the paper, but it isn't much different than what happens in a diffusion enlarger anyway.
    Building it to take a standard holder is a good idea, but you could save that for a V2 since you have lots of material .

    One small problem with using standard holders with paper is that a 8x10 sheet of film isn't quite 8x10 inches, so to use paper you'll need to trim it down slightly. The other problem with 8x10 holders is that they tend to be expensive, though you can get cheap ones that may need some repair and spend some sweat equity. Even with a cheap holder though, it will probably be the most expensive portion of your camera.

    You can process your paper neg just like your prints in the same developer.

  4. #14

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    Paper negatives... 8x10 format... camera making... Make sure you go into f295.org to get all the details you will need. Joe VanCleave (member of f295) is the master.
    Ric Johnson
    Proud member of the League of Upper Midwest Pinholers & f295

    "I think, therefore, I photograph."

  5. #15
    X. Phot.
    Quote Originally Posted by bdial View Post
    . . . One small problem with using standard holders with paper is that a 8x10 sheet of film isn't quite 8x10 inches, so to use paper you'll need to trim it down slightly. The other problem with 8x10 holders is that they tend to be expensive, though you can get cheap ones that may need some repair and spend some sweat equity. Even with a cheap holder though, it will probably be the most expensive portion of your camera. . . .
    Oooooh . . . This could be a trouble spot. I can say from my 8x10 holders that half will accept paper, and others will not. On the holders that won't, the trough on each side rail is too narrow for normal double-weight paper. Film slides in just fine. You may want to ask the forum in advance if a particular make and model of holder will accept a certain thickness of paper. It could save you the heartache of ordering a holder that won't work with certain papers.

  6. #16
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    Film and film holders are more readily available and less expensive than 5x7 or 8x10. The experience gained in building and using the smaller size may be valuable when designing a larger camera. Larger film (or paper) sizes do have a modest advantage in image quality.

    This is because the image blur is proportional to the pinhole diameter. The ideal diameter (for maximum sharpness) increases in proportion to the square root of the focal length. Therefore, if the focal length is doubled, the blur is only 1.4x as large. For the same reason, wide angle pinhole cameras can have better central image sharpness than longer focal lengths. However, edge sharpness and illumination suffer in wide angle pinhole photography.

    I prefer film over paper in the camera. It is easier to capture quality images on film. Paper has limited color response and demands more careful exposure. Exposure errors in film are easier to correct in printing. When printing, images on film can be interpreted in more ways than those on paper. The higher cost of film is small in comparison to the investment of time and energy in making and using pinhole cameras. With care, film can be processed in the same developer as paper. I often do this to increase contrast. It may also increase grain, which shouldn't be important in an image that has little detail and might never be enlarged.

    For well over a hundred years there has been much (and sometimes heated) discussions on the optimum pinhole diameter. For maximum sharpness it is more critical than many claim. I prefer Pinhole Designer with a user constant of about 1.4 for optimum on-axis sharpness with film. With this criteria, the diameter for a 170mm focal length could be about .43mm mm for film and a little smaller for paper. The diameter might be increases a bit to sacrifice a little central sharpness for better corner sharpness with wide angle pinholes. Few lenses make an image as unsharp as a pinhole photograph. Sharpness is not the main goal in pinhole photography. More important is how pleasing or effective a slightly unsharp image can be.

  7. #17
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    Well if you're going to get into the expense of 8x10 holders then you may as well buy and old 8x10 field camera, like a poco or korona or such.

    I would suggest making some nice, low tech wooden boxes and just make a door to slip some film in and clip it into place. You don't need anything fancy like a holder for pinhole- the film can be quite curved and still give a nice result. In fact, a paint can with a hole in it might be just the thing. If you ant to get fancy you could come up with some sort of bellows or sliding mechanism to optimize the effective focal length.

    For film size, let me suggest 5x8- you get two sheets per 8x10 and the print size is quite nice. You might try some ortho film, that should be fine and you can easily develop it by inspection, which is handy with pinhole.

    It's pinhole- be inventive and quirky and you'll get something nice!
    "Only dead fish follow the stream"

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  8. #18
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    Howdy and thanks for your responses thus far. I am going to stick with the 8x10 and a focal length of 170. From there, I will play with different diameter holes.

    As for film holders, it nearly appears that where others live, they are a 5c a dozen! OK, maybe not quite, but around here they are not necessarily gathering dust in every second garage. If there are more cameraís in the future, Iím sure I could come up with one to suit a 4x5 holder (which makes more economical sense if I want to use film). Also, this is kind of an exercise in playing with power tools as much as taking photos (Geez, Iím starting to feel like Tim Allen all of a suddenÖ.must go and find a raw steak smoothie). I must, though, resist the urge to go and buy new materials! I checked last night and found that the majority of MDF I have is 12mm, so itís going to be a chunky unit! (My Ďotherí hobby for a while was slot cars. I built a slot car track out of MDF, hence why I still have a bit laying around)

    So, tonight when I get home from work, Iíll draw up some plans and see about making a start on the weekend.

    I do have many more questions in relation to using paper negís, but I am sure that these can wait (donít want to put the horse before the cart!)

    Cheers

  9. #19

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    I built a pinhole with 4x5 film holders and it works great. I have a 4x5 enlarger so that's what I went with. A resource I used was on YouTube and it was a 10 part series on building a 4x5 pinhole camera. Just type that in and it should show up. Of course everyone modifies the instructions to fit their own needs and intuitions and I made a few myself. Anyways, this will give you an idea on a design for a holder style pinhole and you can just size up the basic concept to fit an 8x10 holder. A lot of the stuff he goes through is just basic woodworking so you can fast forward through some of the parts. Have fun.

  10. #20

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    8x10 is good. I do a lot of work with 11x14 paper negatives, but in a tin can, not in film holders. 4x5 photo paper has to be cut down slightly to fit into a 4x5 film holder. I don't know if the same thing applies to 8x10 or not; but it may be a consideration.

    For paper negatives... I've tried a lot of papers and have settled on two. Oriental Seagull mat surface RC Grade 2 and Foma Variant 312. The Seagull is twice as fast, has incredible detail but is a little flat for some people's taste. Foma Variant has a lot of detail and is more contrasty. Still, the Foma picks up a pretty good tonal range. I've tried Ilford MG RC and found it way too contrast with blown-out shadows and highlights. Most other papers lack a good tonal range as well. I haven't tried Arista RC Grade 2, but a lot of people use it with good results. See what works best for you.
    Pre-flashing the photo paper will reduce contrast and may make Ilford workable.

    Also, paper negative do work better on overcast days; but I've had excellent results in pure bright sunlight when the brilliant sunshine covers the entire scene to be photographed. It is when the scene has sunlit highlights as well as shadows when paper negative don't work so well.

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