Today is Ash Wednesday, on which we celebrate the partial combustibility of plant matter, and begin 40 days* of sacrifice and all-you-can-eat fried seafood. I’ve decided to observe Lent by simplifying my photography. I will use a single lens, forsaking** all others: the smc PENTAX-A 28 mm f/2.8. And though I’m not making a firm commitment, I intend to make and post a photograph with the lens each day of Lent.
There is one small problem with starting the project today. I don’t have that lens yet. I just bought it from a fellow PDML member, and it’s not going to be delivered until tomorrow. This leaves me with a photograph to make, and no lenses to use. What to do?
I made a pinhole aperture. I have a set of manual extension tubes that consist of a camera-facing K-mount, a set of inserts of different sizes, and a lens-facing K-mount. The parts all thread together. I put a sheet of heavy-duty aluminum foil between the threads of the two mounts, mounted the assembly to the camera, and poked a hole in the foil with a pin. The 0.5-second manual exposure above, at ISO 100, is the result. I inadvertently switched the camera to JPEG mode instead of my usual raw format.
Based on Fred Parker’s Ultimate Exposure Computer, I estimate the focal ratio of the pinhole to be about f/90. The image was visible through the viewfinder, though I had to shade my eyes from outside light.
Some of the other exposures were less successful photographically, but interesting:
I’m not sure what causes the colored streaks when shooting into the sun. My guess would be diffraction around irregularities in the periphery of the pinhole.
* For large values of 40. Easter is actually 46 days after Ash Wednesday. Apparently they don't count Sundays. I was going to title this project 28 | 2.8 | 40, but since I plan to photograph on Sundays, I thought it would get confusing when the image numbers exceeded twoscore. [back]