A DIY Pentax Light Meter Shade
I attended a John Wimberley photography workshop this spring. I learned a lot about film exposure and developing and fine B&W photography controls. To help with exposure accuracy, especially in backlit situations, John uses a custom-made lens hood for his Pentax Digital Spot meter. I decided to replicate his shade for my meter (which is also a Pentax Digital Spot meter). Here's a photograph of the end result.
The Recipe
- Get a B+W 40.5mm --> 52mm step-up adapter.
- Get 4" length of 2" OD 6061 aluminum tube from onlinemetals.com. They'll cut it to length for you if you choose. The cut they made for me wasn't 100% square, but close enough for my needs.
- Get a package of JB Weld.
- Get some self-adhesive black flocked paper from Edmund Optics. (Smaller quantities available here.)
- If you drink caffeine, stop for long enough to regain steadiness in your hands.
The Procedure
Use the JB Weld to glue the aluminum tube inside the 52mm threads of the step-up adapter (that's the grey stuff you see in the photo above). Other epoxy products should work fine; JB Weld worked well for me. Be careful to avoid getting any epoxy on the 40.5mm threads of the step-up adapter. Allow this assembly to cure fully.
Cut a piece of the black flocked material to fit inside the tube. Carefully (this is where the steady hands come in) install it inside the tube. I accidentally ordered the non-self-adhesive version of flocked paper from Edmund Optics. I used double-sided tape sold for securing carpeting to adhere the flocked paper to the inside of my shade. I had several unsuccessful attempts at attaching the paper, and several spoiled pieces of flocked paper. Finally, I used several bits of the waxy backing paper from the carpet tape to keep the flocked paper from fully adhering to the inside of the tube until it was positioned correctly. Then I removed the bits of backing paper one by one using tweezers and got the flocked paper installed the way I wanted.
The Result
The result of this is a lens shade for the Pentax Digital Spot meter (the concept should also work for the Pentax analog meter) that blocks out all the extraneous light you can without vignetting. Now it's my understanding that the lens flare of the measuring system (the meter) should match that of the recording system (the camera+printing system). With my dandy new meter lens shade, I probably have a mismatch in my system. Time will tell.
Another idea from John Wimberley: That 4" of gleaming aluminum makes a great place to apply a cheat sheet of useful data like: film speed vs development time; bellows compensation; a zone scale; filter compensation data. In fact, here's a beta of the data sheet I plan to laminate and tape to my lens shade: Pentax Lens Shade Data Sheet