i have been shooting large format with lenses for years, and was interested in making a large format lens-less (pinhole) camera. right now i regularly shoot 4x5 and 5x7 and i wanted to go maybe to 7x17 or 8x20 and shoot paper negatives. i have micro drilled shims, and plans for making the "box" ... has anyone every made a really BIG pinhole camera? will i have any problems with image circle / coverage ?
thanks in advance! john
John:
I built an 11x14 Pinhole several years ago as a bridge to larger format cameras. My 11x14 pinhole has a focal length of about 5" and uses a .016" pinhole. This arrangment covers 11x14 although you do get the light falloff characteristic of pinhole shots.
If I remember correctly, the relationship between focal length and image circle is approxiately 1:3.5. Thus, a 1" focal length pinhole camera will produce an image circle of 3.5". For the larger film formats you will need a minimum FL starting at about 5-6 inches.
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Dave:
Out of fascination, can you remember what the length of exposure was under "sunny 16" conditions?
thanks dave - if / when i build it i'll post my results- john
Go to:http://home.online.no/~gjon/pinhole.htm. Jon has alot of useful info. If you also plug in "homemade cameras" into your browser, you will get so many sites!!!!
I built an 8x10 pinhole a while ago. It has a focal length of 8.25" and an f/346 . I purchased a laser-drilled pinhole from Lenox Laser - they drill these in 1/5000th stainless and mount them on a 3/4" disk.
The camera itself is a plywood box with an 8x10 spring/back from an old Kodak. I have only used film so far, but you could use paper in the holder as well. I initially had recessed the disk (with pinhole) and made a 1.4" hole in the wood, but the edges of the wood showed on the negs.(the disk with pinhole is mounted on the inside surface of the box), so I had to enlarge the hole to about 3/8" -
I like it alot!
To combat light falloff you might consider building the camera with a curved film plane. I made a 4x5 out of a coffee can that works beautifully, and I recently completed a 5x7 version. See the 4x5 at http://unblinkingeye.com/Articles/PinCam/pincam.html.
This does not answer your question, but I thought I would chime in. I am a LF in focus kinda guy. But, a while back I purchased a 4x5 and 8x10 Leonardo(used) and I must say they can be a kick in the butt. I carry the 4x5 with me most of the time and I find playing with the pin holes to be a great break. There is no dissatisfaction in a soft focused finished print because it's "supposed to be that way" so a lot less pressure.. And I have a lot of fun trying to play around with motion. It's also a great way to introduce a kid to photography at a very basic level. And you really can have cars and people go by and not get in the photo. I purchased my 4x5 at almost new price and the 8x10 for $15.00 with a holder. Check out Eric Renners(sp?) Book and site.
Good Luck,
Mac
There's a great pinhole discussion forum at www.pinhole.com
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