SLR to pinhole camera conversion

[reportsfromluke]

I have this old Canon SLR. I was thinking about using a plastic body cap to

convert it to a pinhole camera. I would use a high 'e guitar string (someone

stole my vernier calipers so I couldn't tell you exactly how thin it it) heated

in the gas stove elements to put a hole through the exact center of the cap. I

would then use a cable release to take pictures with it. Would this work out? If

not, tell me about any holes in my idea and if it's possible to fix them. Thanks

a lot.

 

best,

 

-R

[stephen hazelton]

If you visualize light passing through a pinhole, you want the pinhole material to be physically thin, not thick like a body cap. So consider drilling, say, a 1/4" hole through the body cap, and then tape foil or thin sheet brass or other material over the hole and put your pinhole in that instead. This also lets you change pinhole size without buying a new bodycap.

[pvp]

Several problems. The biggest is that the plastic in those body caps is really thick, so you'll end up with a .012" hole in plastic that's probably 1/16 inch thick. Rather than launch into a detailed discussion of pinhole theory (I'll let you do that research yourself) suffice to say it won't work. A second problem with this plan, is that a hot wire is going to make an irregular hole that is a lot larger than the diameter of the string.<P>

 

A better idea (still not the best) is to get some thin brass shim stock from a hobby store, then drill a hole using a very small drill bit. Make a large enough hole in the Canon body cap to be sure it won't interfere with the cone of light from the pinhole to the film, and mount the brass sheet with electrical tape. I did this with a number 78 drill, .2mm diameter. <P>

 

Here's a photo taken with that pinhole, mounted on a Canon A-1:<P>

 

<img src="http://farm1.static.flickr.com/153/345096588_d830d10256.jpg">

[reportsfromluke]

Thanks a lot! I look forward to experimenting with this (come spring).

[kelly_flanigan1]

The way the Nikon School back in 1969 did it was to use a black body cap with a big 1/4" hole; then the hole was covered with a piece of aluminum foil with the homemade pinhole. I think it was John Slack that had one then at the school. There is an optimum pinhole size for best sharpness.

[kelly_flanigan1]

Then one can evolve to getting a simple lens with the focal length equal to the body cap to film plane; and open up the pinhole way way more!

[kelly_flanigan1]

I think both old Spiratone and Cambridge at one time in the 1960's had a spy bodycap with a lens tacked under it; something like F 45 rig. Also there was the sideways shooting filter attachment rig too. Even with Exakta VX slr there was the pinhole bodycap from Seymours Exakta too.

[jason_cook1]

http://www.freestylephoto.biz/sc_prod.php?cat_id=2203&pid=5639

[stephen hazelton]

Kelly, something like what you describe is still available- have to order from overseas. I remember it described also as a "pan focus" lens.

[justin_thornton1]

I have found this "Lens in a cap" That is sort of like a pinhole in a way.

At http://www.loreo.com/pages/products/loreo_lenscap.html

 

You can stop it down to f/64. other selectable ones too. I won't go into detail about it just read the full discretion above link

 

Personally I use this as my dust cap when I actually don't have a lens attached. Its small only 1.5cm from the lens mount. So its really small. (the rear dust caps are bigger.) it's a handy little lens that's about 35mm.

 

I have also tried the taking a dust cap of the camera and burning a hole like you though and Alan davenport is right it makes a irregular hole. Also if you use a small drill bit, clamp the cap down tight on a press drill or else you have the same problem.

 

The best solution I have found is drilling a 1 cm (~2/5 in) or what ever hole dead center in the cap and tape a peace of tin foil or other thin mettle and poke a whole in there

 

Hope it helps, and I recommend the Lens in a cap its neat.

Justin

[lemastre]

People who use brass stock often make the hole by tapping a dimple into the stock with an

icepick or other small point and then filing the bump that's formed on the other side until a

tiny hole appears.