Mamiya Press Pinhole w/Mamiya 6x7 back --Help, Advice, Comments, Suggestions? Newbie!

[jmarsh]

Hello People,

On a lark, I sent a Mamiya Press (front) body cap to be laser-drilled with a .24mm (that's point two four millimeters) pinhole, with the intention of using 120 film in a Mamiya 6x7 back.

Question being, will a .24mm pinhole on a Mamiya Press camera with a focal length of --best estimate here-- 70mm have enough coverage to utilize all of a 6cm x 7cm negative? I've so far been unable to gather the info from internet searches.

To repeat, it was on a lark --no research (stupidly?), little forethought-- and it's only now that I am wondering, have I simply created something useless and wasted money?

Thanks for ANY help...

joe

 

[Jim Jones]

For a focal length of 70mm I'd use about a .275mm pinhole for optimum on-axis sharpness, or slightly larger to improve corner sharpness. If your pinhole is drilled directly in the body cap, it will illuminate only a small spot in the center of the image area. If so, the hole can be enlarged to accomodate a pinhole made in very thin material. Properly made pinholes have good wide angle coverage: 70mm should be no problem on your camera. Two sites with much information on pinhole photography are http://www.f295.org/Pinholeforum/forum/Blah.pl and Dead Link Removed

 

[summicron1]

yeah, you want the hole in really thin metal so that the light can enter and exit the hole at an extreme wide angle -- if it is there is practically no limit -- my ZeroImage 4 by 5 pinhole camera gets excellent coverage with a pinhole distance-to-film of 50 mm and even does ok at 25, although vignetting is rather extreme at that distance.

But I'd give it a shot in any event, the plastic in ur lens cap may be thin enough to give you good coverage with a .250 mm pinhole. 70mm is pretty far away.

 

[geoferrell]

On the Mamiya Universal press and the pinhole on a body cap, what type of results did you get? I've got one too and have been studying drilling a hole in the body cap and putting a pinhole on. I tried that with another MF camera and got interesting results. I used aluminum from a pop can and made a pinhole and the results seemed creative. Am wondering about the Universal, the body cap I have extends and is not level with the placement of the lens mount.

 

[bsdunek]

I drilled a Mamiya body cap 1/2 in. and used a very thin piece of tooling copper with a 0.40mm hole cemented behind it. I use the shortest extension tube, which gives a more or less "normal" view and covers the 6X7 format just fine. I haven't tried the cap directly on the body for a more wide angle look. Should make a smaller hole for that I guess.

 

[John Koehrer]

I drilled a Mamiya body cap 1/2 in. and used a very thin piece of tooling copper with a 0.40mm hole cemented behind it. I use the shortest extension tube, which gives a more or less "normal" view and covers the 6X7 format just fine. I haven't tried the cap directly on the body for a more wide angle look. Should make a smaller hole for that I guess.

That's the better method, large hole in the cap and a metal insert/section for the actual pinhole.