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  1. #11

    Join Date
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    Quote Originally Posted by Murray@uptowngallery View Post
    People call the C-3 ubiquitous (found everywhere).

    I have three and can't find ANY right now. (Another 3 victims of my basement). I was going to measure.

    Using the nominal 24x36 mm frame dimensions, not knowing if they are actual, I get 43.3 mm diagonal. That's why my 41.5 mm distance looked so 'normal'.

    Some people get tired of the very wide angle camera constructions, but I like them (say, an f.l. less than half the diagonal length) because they look so different from 'normal' angle of view.

    I have to break the habit of shooting 'normal' subject matter in a 'normal' angle of view pinhole camera. Due to my choice of subject matter, I get what look like blurry normal camrea pics. Very wide angle solves some that for me (called gimmickery by some, however).
    That's exactly how I got into this to begin with. The pictures from the bodycap pinhole - just about normal focal length for 35mm - look, well, normal. Like they were taken with a crummy glass lens. I guess I was expecting some distortion or vignetting. That's why I want to get the pinhole closer.

    If I was going to attempt this with the C2, do I have to remove the whole lens assembly, or should I try to get something to screw into the inside threaded tube that the lens fits into?

    Thanks,
    Louis
    (Paladin1420)

  2. #12

    Join Date
    Mar 2006
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    Related, but slightly off topic.

    My scenario may provide additional input for the OP.

    I used an Argus C4 for the pinhole I'm casually working on currently. It measured 29mm from the pinhole to the film plane. I also hogged out the 24X36mm frame in the body to 24X52mm for a more panaramic format.

    My first tests showed complete coverage of the new frame, but the center of the frame showed overexposure (more like fogging) when compared to the edges....would this be attributed to too large a pinhole diameter? The correct exposure from the film test indicated about 2 seconds in sunny but high, light cloud cover conditions with ASA 400 speed film.

    The other problem I have is with the film advance. I measured 2 1/2 turns of the winder to give me spacing on the first frame. I thought as the diameter of the take up spool increases, I'd have larger frame spacing....but quite the opposite happened.

    Thanks for your replies, in advance.

  3. #13
    Pitxu's Avatar
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    Jan 2008
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    Hi jolefler. I think your film being over exposed in the middle part is quite normal. The distance from the pinhole and the middle partof the film being 29mm, but from the pinhole to the edges of the film will be much longer, in fact you've exgagerrated the effect by having opened out your body to a more panoramic format. For this type of format a curved film back is used in order to obtain a pinhole to film distance uniform. You ask if your problem could be that the pinhole was too big, I would say no. The size of the pinhole is governed by the focal length, that is, there is an "ideal" pinhole size for every pinhole focal length. There is a table here showing focal length, pinhole size and f numbers:http://cgi.ebay.de/Lochblende-fuer-L...QQcmdZViewItem

    This guys pinholes are very good, I use one on my rangefinder cameras.

  4. #14

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    Many thanks for that, Pitxu! It makes much sense. This is such a new project and interest for me I haven't aquired the knowledge to measure the pinhole. I did guesstimate from a similar table that the diameter needed to be about half the diameter of the smallest sewing needle made....I used a sewing straight pin. It's fun for me, I sweat the small stuff too much in my other photographic endeavors, I'm hoping it won't be like that using the guts of a $5 Agfa! But now.....if I can just curve that filmplane :rolleyes:

    Jo

  5. #15
    Pitxu's Avatar
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    jolefler,
    I've been thinking more about this distance thing, I don't know how they do it , but some guys use pinholes equivalent to very wide-angles on large format cameras where the distances are greater, but still keeping the film plane "flat".

    It must be more complicated than I thought



    Pitxu.

  6. #16

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    Mar 2006
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    In case you were following....

    The "over-exposed center" of my pano-pinhole has been solved. Apparently rough edges of the pinhole were to blame.

    I was chatting with my 83 year old ex-wedding shooter Dad, and he came up with that explaination of what was happening. Sure enough, cleaning and reaming the opposite side from where it was punched has yielded even exposures across the 24 X 52mm frame.

    Lesson of the week....don't dismiss the advice of the aging, even should they be strickened with Alzheimer's disease. Thanks, Dad!

    Jo

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