Anybody use pinhole lens cap in Medium Format?

harlequin

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Hello Team,

I understand there are companies that make body caps that are pre drilled or laser etched that turn Medium Format cameras into pinhole camera without gorilla glue and gaffers tape, Finney is a brand that seems to accomplish this feat...

Has anyone tried this item?

Any exposure suggestions?

Anyone have an image or two to share?

I have access to Pentax 645 and older Pentax 67, does anyone here know approx equivalent of angle of view images I have seen look like they were shot with 20mm lens in 35mm format.

Thanks for your input on this..

Regards,

Harlequin
 

RalphLambrecht

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DWThomas

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Haven't tried a commercial one, but as an avid tinkerer, I designed and made a pinhole body cap for my Bronica SQ-A. It works. I could probably play some more with pinhole size optimization, but I've moved on to 4x5 and 8x10 homemade cameras using standard sheet film holders. One minor hazard is the lens mount to film distance limits the maximum angle of view you can get -- there are no retro-focus wide angle pinholes! If working with a camera with a focal plane shutter, a pinhole body cap is almost trivial. The Bronica has the shutter in the lenses so I had to deal with a substitution for that.

An overview In the text at the top of that page there are links to three years of Worldwide Pinhole Photography Day efforts. In general, it seems the smaller the format, the softer the image, thus I've gone up to 8x10 (on X-ray film!)

In general, a pinhole camera is merely a box with a hole in it. The pinhole needs to be in a very thin plate, with the pinhole precisely round with sharp, clean edges, and of suitable diameter for whatever pinhole plate to film distance it sets up. There are probably some cameras where there may be a bit of interlocking that requires an extra trick to be able to advance the film after exposing a frame. One can hope a commercial body cap unit would supply suitable advice on such matters.
 

xya

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I have tried different solutions. the diana F+ has a built-in pinhole setting. I had a pinhole cap for my mamiya rb67 and I had the holga wide 6x12 pinhole camera. they all did not impress me, for my taste pictures were too soft and fall-off too important. then I bought a curved film plane 6x17 vermeer camera. that was much better, no fall-off, see http://www.oddcameras.com/vermeer_6x17.htm, there are lots of instructions how to calculate exposure on my page. and, finally, I have a modified pinhole instax camera http://www.instantphoto.eu/other/pinstax_wide.htm which I tested with instax colour film. because of the long exposures times there is an important colour shift, so pinhole photography seems easier with b&w film.
 

Donald Qualls

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DWThomas said:
One minor hazard is the lens mount to film distance limits the maximum angle of view you can get -- there are no retro-focus wide angle pinholes!
Click to expand...

Well, yes and no. I haven't tried this on my RB67 because the shutters are in the lenses (no in-body shutter, just the light seal flap under the mirror, which isn't instant return) so I'd have to black-hat the exposure. However, with this camera, as with most other SLRs, there's considerable clearance inside the body for rear lens elements ahead of the mirror. Some of the 35mm and digital pinhole body caps I've seen have a cone, with the pinhole mounted well back into the mirror box. As long as it clears the mirror, everything will work fine, and this lets you use projection distances (equivalent of focal length for a non-focusing system) not much more than half the film to flange distance. On rangefinder systems like the Mamiya Press, Mamiya Universal, and Mamiya 6, you're still limited to about half the flange to film, because otherwise you'll get nice, sharp images of your body cap rim in the corners of your frame.

Still, with my RB67, that would let me get down to about 60mm, which is fairly wide on 6x7 film (90 mm is normal). With a Mamiya Press or Universal, one should be able to get under 40mm on film up to 6x9 cm (I don't have one, so I'm not certain what the flange to film distance is).

That said, I have a pinhole setup on one of my plate cameras that lets me shoot on 9x12 cm film -- and the camera plus several plate holders weighs less than my RB67 body and a single roll film holder. Guess which one would get out more for pinhole...
 

narsuitus

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Since I was using medium format cameras with fixed lenses and medium format cameras with twin lenses, it was easier for me just to buy a relatively inexpensive dedicated medium format pinhole camera.


Holga Pinhole by Narsuitus, on Flickr
 

narsuitus

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harlequin said:
Any exposure suggestions?
Click to expand...

6x9cm image size
0.3mm pinhole diameter
f/170
51mm distance between pinhole and image plane
ISO 100 Fomopan black & white film

Shutter Speed Exposure Suggestions (corrected for Fomopan reciprocity failure)
2 seconds Bright Sun
7 seconds Slightly Cloudy
21 seconds Cloudy
1 minute Overcast/Shade
2 1/2 minutes Sunup or Sundown
 

MattKing

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Ariston said:
I just made on for myself to try on a DSLR, just for curiosity's sake.
Click to expand...
Be cautious with doing this.
As I understand it, this is a great way to add dust to the screen in front of the camera sensor.
 

Ariston

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MattKing said:
Be cautious with doing this.
As I understand it, this is a great way to add dust to the screen in front of the camera sensor.
Click to expand...
Thanks - I'm already done with the experimentation. I am comfortable cleaning the sensor, also.

It was interesting. I got okay results using a needle into electrical tape and twisting it a lot to try and smooth the edges, but never as good as a laser cut hole would be. I also changed the focal length by using extension tubes - also interesting.
 

Donald Qualls

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Ariston said:
It was interesting. I got okay results using a needle into electrical tape and twisting it a lot to try and smooth the edges, but never as good as a laser cut hole would be. I also changed the focal length by using extension tubes - also interesting.
Click to expand...

I've got a pinhole body cap on one of my M42 SLRs, and I've done the same -- mounted extension tubes to vary projection distance. I've also done handheld pinhole shots; I had a developer years ago that would get the Tri-X available then to EI 5000-6400, which is fast enough to shoot handheld in bright sun at f/180 (if you've got steady hands). Of course, cats have fast enough reflexed to react to 1/4 second shutter while it's still open...



Pentax Spotmatic SP, pinhole body cap f/180, Tri-X EI 1600, Diafine
 
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