Micro Four Thirds Pinhole "Lens" - 11mm FL by awdemuth

Last crawled date: 3 years ago

Are you tired of your modern lens with it's tack-sharp focus, vibrant colors and incredible contrast? Do you wish your photos had strangely colored areas, hot spots and heavy vignetting? Is f22 entirely too fast for your tastes? Well strap in, folks, I have just the project for you!
When I first started my photography class in high school, I fell in love with alternative photographic methods. Whether making a slit scan camera or playing around with strange processing effects in the darkroom, I was into it. Pinhole cameras were my favorite though: empty film box, some tape, a piece of aluminum foil and a needle: instant camera!
Pinhole photography in the digital world admittedly loses some of it's charm, mostly due to the convenience factor: some of the fun of pinhole photography was wondering exactly how the scene was framed or if you had the exposure right. What convenience takes away, it also gives back in spades: now you don't have to wait until you get back to a changing box to put new film into the camera just so you can take one more picture!
Thanks to hstahl for helping out with the MFT mount!
This STL is just a cap to affix a pinhole aperture to. You will still need to make your own aperture. I followed the excellent instructions on how to make a precision pinhole at (LINK DOWN!!!http://www.withoutlenses.com/articles/how-to/drill-your-own-precision-pinhole-aperturesLINK DOWN!!! read at end of description). Any maker here will probably have most of the tools mentioned and should be able to improvise for anything you don't have (I used my digital calipers instead of a micrometer), so all you need is time and patience. Though, if you lack the patience like I did in high school, aluminum foil and a needle will work, just know that your photos are likely to look even worse than what I posted.
The focal length for this is 11mm: this is as short of a focal length you can have with a pinhole and have an image circle that mostly covers a MFT sensor. Ideally, the pinhole diameter should be 0.14mm, or roughly f80 for this focal length. Calculations for pinhole sizes and daylight exposure estimates can be found at http://www.mrpinhole.com/calcpinh.php
The aperture I used was designed for my 20mm FL pinhole cap (which I'll post later) and is roughly f115, which is why I think I have such poor colors and so much diffusion in my photos. Once the pinhole was made, I cut it and taped it to the backside of my printed adapter with duct tape that I then covered with electrical tape (to avoid internal reflections).
IMPORTANT!!!! Since without lenses is down, here is some supplemental information:
How to make a quality pinhole: this is from user JoeVanCleave on from http://www.f295.org/main/archive/index.php/t-13823.html and is roughly how I made mine
04-14-2009, 11:24 PM
I use 2 mil thick brass sheet, available at hobby stores in the States. K & S is a common brand; it's also available at most True Value hardware stores in their K & S display. I use a sewing needle, the eyelet end pushed into a small piece of round wooden dowel to use as a mandrel; don't push the needle completely through the brass unless the shank diameter is your desired size (for longer focal length cameras, perhaps.)
I spin the needle until it barely penetrates the brass (against a soft surface like cardboard), then sand the bottom side with fine emory paper, and twist/penetrate again, then sand a bit more. Once you think you're in the ballpark of the correct size I'll estimate the diameter using a loupe slide viewer and a millimeter scale. I place the piece of brass against the backside of the scale so that the pinhole is adjacent to the markings on the scale, then backlight the hole, with enough light on the scale side to read the measurement. Using the loupe I can estimate the diameter to within a fraction of a millimeter (i.e. 1/4, 1/3 or 1/2 millimeter.)
It's also important when doing this procedure to look for burrs and other irregularities in the hole; a simple spin/ream of the needle, with little pressure, usually clears the burrs. Also try blowing real hard through the hole, that helps sometimes.
The idea is to slowly ream the hole out, while sanding down the backside dimple, while keeping the hole uniform and burr-free, all the while you approach your target hole diameter (in fractions of a millimeter.) This method is "close enough" in accuracy I feel for all but the most scientific of pinholers.
What happens sometimes is I'll get real close to the ideal diameter, but the hole still has a burr or two; an additional ream and I've gone too wide. I'll just start over again. Sometimes it takes two or three tries to get the correct sized hole clean and circular. It's okay, take your time; the better quality hole will yield higher quality images; the extra time is an investment in your future imagery.
~Joe
PS: I use a pack of sewing needles of various diameters to choose from, but usually the smallest size is what I end up using, unless it's a real long focal length box camera.