After buying my Ricohmatic 225 TLR, which takes Bayonet 1 accessories, I didn't want to spend $25 or $50 US for a real Rollei Bay 1 lens shade. So I made one out of a plastic plumbing piece. It's not quite as effective as a real (square) Bay 1 shade but is very affordable.
Go to a store that carries plumbing supplies and buy a 1.5" test cap. At my store they called them "soft poly" test caps and they come in gaudy colours like blue and orange. I paid a little over $1 CDN for my blue one. I later saw the 1.5" ones in black at a different store.
When you get it home carve a circular hole in the end of the test cap using a sharp utility knife. The hole should be about 1.45" in diameter. Try to get the hole centered. Next, you will enlarge the hole in 3 places for the ears of the bayonet. Cut them and the hole until the shade will fit snuggly over the lens bayonet. (Note that this shade just friction fits over the bayonet and doesn't actually turn and lock, though you theoretically could do that also.)
On my camera the viewing and taking lenses are close enough together that the shade hit the viewing lens when I attempeted to install it. So I carved out an arc from the back of the shade, at the top, of about 0.3 by 0.7" to make room. Depending on the spacing of your camera lenses you may have to do the same.
Below is a scan of the back (bayonet) side of my lens shade. It will be life size if your monitor is set to 75 dpi. You can also see the carving I did at the top to allow it to fit under the viewing lens.
Next you will need to lock your shutter open on B and check for vignetting. You will probably have to cut off about 1/4" to 1/2" to eliminate corner vignetting. The final length of my shade is 1.05" long. This may be different on your camera depending on its focal length and amount of lens recess.
Finally, you will need to finish the inside. If you managed to find a black one then just remove the sheen with some coarse sandpaper. If you have blue or orange rough up the inside and paint it using Testors flat black enamel (model paint). Another idea is to glue blacked flocked paper (that Edmund Scientific sells) on the inside surfaces.
Your sub-two dollar lens shade is now ready to use.
Click here to see the final product and my Ricohmatic 225 TLR.
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