Making a Large Format Camera

[S. Heslop]

My uncle asked me if it wouldn't be too much hassle to make a pinhole camera that takes 5"x7" film, and was probably thinking of just a box with a hole in it. But I can't seem to help but make things as unnecessarily complicated as possible. I spent a while thinking about what features I myself would want in a camera, and decided the two big ones i'd want would be a way to take more than one shot without needing to use a changing bag/ dark room to replace the film, and also the ability to change the focal length. So after deciding the best way to take multiple shots would be large format style film holders, and a bellows extention would be the best way to change the focal length, I effectively ended up with a design for a chunky over-built large format camera.



Most of it will be made from wood, but to try escape the monotony of wood I'm going to have a go at casting the parts for the round rail it all mounts to.



I'm a little unsure about the mechanism for focussing. I'm sure i've seen something like this before, with a tapered wheel driving a bar. No idea what they call this sort of thing though.




Today I got some of the wood cut. I really made a mess of the process and wasted more oak than I'd have liked.

I've got to be honest i've really gotten tired of woodwork lately. After i'm done with this project i'm thinking I might try sell a bunch of the tools I could live without and then buy a milling machine.

[DavidA]

Just thinking.

Couldn't you use A4 photographic print paper to produce a large negative image.
Then use a modern printer to convert it to a digital positive for viewing ?

Dave.

[S. Heslop]

Just thinking.

Couldn't you use A4 photographic print paper to produce a large negative image.
Then use a modern printer to convert it to a digital positive for viewing ?

Dave.

That's my uncle's plan actually, using A3 photographic paper. It'd be a hell of a lot cheaper than trying to use regular film, that's for sure.

[efrench]

Xray film is another inexpensive option.

Have you visited http://www.f295.org?

[chipenter]

An enlarger lens is another option .

[SwarfnStuff]

Hmm,
   Just me thinking here. 
  Uncle asked for a large format pinhole camera and we are making a far more complicated jigger. Bit like the camel being a horse designed by a committee??
                       
   Anyway, if you can get a suitable lens (cannibalise an old instamatic perhaps) it would let more light through with shorter exposure times. I envisage uncle standing, bent with his head under a black hood focusing an upside down image before putting the paper /  film substitute in and exposing his masterpiece.
Good exercise for the grey matter though.
  So next will be the tripod??
John B

[efrench]

http://www.f295.org/main/forum/ will get you to the forums which appear to be still active.

[Alan Haisley]

If it's a true pinhole camera it doesn't need a focusing mechanism. Pinholes have near infinite depth of field.

[Will_D]

Xray film is another inexpensive option.

Suggest you Google "Panchromatic versus Orthochromatic film emulsions and their responses".

Pan: Sensitive to most of the visible spectrum
Ortho: Sensitive to one base frequency
Xray: Sensitive to Xrays !!
IR: Sensitive to IR end of spectrum
UV: (If you can find/afford it) Sensitive at tother end of spectrum
Litho: Specialist films sensitive to bright ligt, no spectral curve used for phot engraving and also "Tone sparation techniques and Solarisations effects. (Note all these can be done digitally!)

[efrench]

Xray film is another inexpensive option.

Suggest you Google "Panchromatic versus Orthochromatic film emulsions and their responses".

Pan: Sensitive to most of the visible spectrum
Ortho: Sensitive to one base frequency
Xray: Sensitive to Xrays !!
IR: Sensitive to IR end of spectrum
UV: (If you can find/afford it) Sensitive at tother end of spectrum
Litho: Specialist films sensitive to bright ligt, no spectral curve used for phot engraving and also "Tone sparation techniques and Solarisations effects. (Note all these can be done digitally!)

Recommend you visiting the Large Format Photography forums: http://www.largeformatphotography.info/forum/index.php.  Many of the posters there are using X-ray film very successfully.

[PK]

X Ray film is placed behind an intensifier plate coated with a material that fluoresces when x-rays hit.  So XRay film is visible light film. Not sure about it's contrast curve, but I suspect it would be a high contrast film which would make it good for landscape shots....

[NormanV]

It is possible to buy direct positive paper from Ilford (Harman Group) that saves all the messing about scanning a negative print.

[S. Heslop]

Thanks for the suggestions.


Got the rear and front standard partially made. They're pretty shoddy and not as square as i'd like, but it shouldn't be too much of a problem.




Also got the front... thing clamped up.



I think next i'll be trying to make some patterns, which should hopefully be a bit more interesting. At this point I wish I just made a box and got it over with, but alas~

[RotarySMP]

Nice work, cool project. I made a 4x5 back in the 90's. A copy of a Tachihara, flat bed of wood with brass fittings.

Since your uncle will only be contact printing paper negatives, almost any lens will give an improvement on a pin hole. Before I picked up a scratched rear element Linhof/Scheider 150 for a song, I used a brass plate with a 1/8" hole drill in as an aperture, and a pair of Rolleiflex close up lenses double sided taped to each side. The black plastic cover from the close up lens sticking to the tape was the manual shutter. work surprisingly well, and shortened the exposure times from the pin hole considerably.

Not sure what this will go to, but could be a very cheap solution.
http://www.ebay.co.uk/itm/Carl-Zeiss-TESSAR-250-4-5-5632-Large-format-plate-mount-Great-condition-/122191048020?hash=item1c73276d54:g:bXQAAOSwImRYCH42

Often shutters are more expensive than lenses.
Mark