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View Full Version : 7x17 pinhole camera/box camera help.....



Matt Magruder
9-Jun-2004, 11:03
Im interested in designing/building a 7x17 pinhole camera with the end result being contact printing the images. Im interested in it being a fairly wide angle (of course) and perhaps holding only a single sheet of film at a time or maybe trying to design a way to mount a 7x17 film holder. does anyone have any experience with creating and making cigar box cameras and/or pinhole cameras in the larger than normal formats (7x17 etc)? The basics Ive been able to determine are that a pinhole creates an image circle of about 150degrees therefore an image circle of 20inches would be created if the focal length (dist from pinhole to film plane) is about 6inches. the pinhole (from reading some links and websites) should be about .5mm in size. does this sound correct or even close to anyone? I realize that because of the large size of the film there may be dramatic light fall off and vignetting in the corners and edges of the resulting negatives but this is partly the endearing quality of it for me. I like the resulting look. basically Ive come up with a design that would employ a 20inch wide by 7 inch deep by about 7-8 inch tall box with the abiliity to change out the pinholes on perhaps a removeable holder of some simple design. what are anyones thoughts on this or perhaps similiar experience in creating something like this...... also.... in regards to actually using a lens what are good focal length lenses that might work for a fixed focus box camera like this in the 7x17 format? Im thinking along the lines of barrel lenses and the like because the exposures will like need to be fairly long I would assume. any thoughts on this would be appreciated. thanks in advance.

Moe_4073
9-Jun-2004, 11:27
The website "www.mrpinhole.com" has online calculators which you may find useful as well as links to other pinhole sites. From experience, the mrpinhole's online calculator will give you diameter and suggested focal length to give very even coverage of your negative (which is what I want in pinhole camera). To get wide angle exposures you have to oversize the pinhole for shorter focal length which will lead to a loss of sharpness. For comparison, a wide angle pinhole camera for 8x10 would have around a 3 11/16" focal length and .036"dia (#64 drill) pinhole whereas (from mrpinhole.com) the online calculator would suggest a 6.75" focal length and 0.022"dia (#74 drill) pinhole for a camera to cover 8x10. Buy a fair amount of brass shim stock and experiment. Black 3/16" foamcore board is nice for prototyping boxes by the way. Regards,

Donald Brewster
9-Jun-2004, 13:30
Take a look at Jon Grepstad's very informative web site. I'm enamored with his 20x24 collapsible box camera. Jon designs and builds LF and pinhole cameras. His website is at http://home.online.no/~gjon/jgpincam.htm

tim o'brien
9-Jun-2004, 13:49
To minimize light falloff, make all sections of the film/paper equidistance from the aperture. This is accomplished by using a curved back. I have in mind a 120 based camera that would use 10 inches of film per shot. Think of a baseball field where the aperture is home plate and the film holder is against the outfield wall. Easy to build if you have a router with a radius fixture on it.

Sharpness is a function of perfectionof the pinhole, thickness of the aperture plate, and optimum size for effective focal length. May I suggest...

http://www.mrpinhole.com/calcpinh.php

tim in san jose

Jim Galli
9-Jun-2004, 13:56
For economy you might consider using aerial roll film. It comes in 5" and 9.5" wide rolls and can be cut to your length. There is a seller on Ebay "mrfoto" I think, that always has some. The 9.5 plus x is very nice. I began and never finished a 9.5 X 36 inch pinhole. The curved back stalled me. No good reason really, just one of many projects on the "waiting" pile. Hadn't thought of it in a while..............hmmmm.

Matt Magruder
9-Jun-2004, 14:40
thanks for all the advice thus far. per my hours of reading (ahem.... working I mean) Ive become interested in the pinhole idea more than anything and Im planning on putting together some mockup foamcore concepts in the near future in order to experiment with pinhole sizes and focal lengths. Im interested in perhaps having the film plane be slight curved to help in distributing the light as evenly as possible but Im also still kind of interested in the effects the uneven lighting has on film layed flat. Or even perhaps using two pinholes to create two slightly overlapping imges on the same 7x17 film sheet. Im very intrigued by the panoramic format and love the look of a pano format with wide angle shots. all those online calculators are a huge help.... thanks.

robert colognoli
10-Jun-2004, 23:48
Hi, Sorry,the text in French, but may be interesting for you.

www.galerie-photo.com/stenope.html

cheers, Robert.

Matt Magruder
11-Jun-2004, 09:15
now I really wish I spoke/could read french. that seems like a really interesting article.

Øyvind Dahle
11-Jun-2004, 17:59
I would limit myself to 125° on a flat film, but maybe 150-170 on a curved, unless you want to have really dark corners.

To make the film stick, use a "post-it" glue-spray. (3M and Gepe)

I have bought a suitcase on a flee-market, and I'm going to add black paint inside, pinhole, shutter and a light plate to stick my film or paper on. Even if I get it light tight, I'm going to add black tape on the outside.

I might be using several formats for this, 11x14", panoramic and square.

Not speaking french, try this: http://www.world.altavista.com/babelfish/trurl_pagecontent?url=http%3A%2F%2Fwww.galerie-photo.com%2Fstenope.html&lp=fr_en

Øyvind:D

jongrep
17-Oct-2015, 23:43
Take a look at Jon Grepstad's very informative web site. I'm enamored with his 20x24 collapsible box camera. Jon designs and builds LF and pinhole cameras. His website is at http://home.online.no/~gjon/jgpincam.htm

Please note that my ebsite is moving to: http://jongrepstad.com/

Jon Grepstad