Back in high school, I designed and built a slide rule exposure calculator to improve my macro photographs:
The base consists of three layers of thin cardboard glued together with Elmer’s Glue. The three slides have three layers of thinner white cardboard glued together, with offsets forming tongue-and-groove interlocks, topped with yellow paper for that true slide rule look:
Judging from the seams, I covered the hand-drawn scales with “invisible” matte-surface Scotch Tape. Worked well, if you ask me, and still looks pretty good:
The reverse side carries instructions under a layer of packing tape (which hasn’t survived the test of time nearly as well), for anyone needing help:
A closer look at the instructions:
The slides still move, albeit stiffly, and it might be usable.
I vaguely recall extension tubes on an early SLR, but memory fades after that. Getting the exposure settings close to the right value evidently posed something of a challenge and, given the cost of 35 mm film + development, it made sense to be careful.
Fortunately, even today’s low-end cameras make macro photography, at least for my simple needs, easy enough, with the camera handling the exposure calculations all by itself:
I’m definitely not on the level of a professional insect photographer!
Randy’s observation to Amy in Neal Stephenson’s Cryptonomicon comes to mind:
“… One of the most frightening things about your true nerd, for many people, is not that he’s socially inept — everybody’s been there — but rather his complete lack of embarrassment about it.”
“Which is kind of pathetic.”
“It was pathetic when they were in high school,” Randy says. “Now it’s something else. Something very different from pathetic.”
“What, then?”
“I don’t know. There is no word for it. You’ll see.”
The Smell of Molten Projects in the Morning 