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View Full Version : Lens board for my Rapid Rectigraphic 8-12-17 in a speed tested Gundlach shutter



Mike in NY
12-Mar-2019, 09:34
I've been making my own lens boards for about seven years now. I got my start in LF through platinum/palladium, wet plate, and salt printing at the Center for Alternative Photography in NYC around 2011. I enjoyed it so much that I invested in an old ANSCO 8x10 camera to work on my own, beyond the studios at the Center. And that took me down the path of acquiring some very large and unusual lenses, which led me to make my own boards. I build Stickley furniture reproductions, so making my own lens boards wasn't difficult.

I typically use Mahogany or Cherry, but yesterday I took the day off to enjoy my birthday and used the time to make a masonite board for a sweet little 8-12-17 inch Rapid Rectigraphic lens in a Gundlach shutter. I've been shooting 8x10 film for about five years now, and am eager to see if the 17 inch configuration will give me a large enough image circle (the lens was primarily promoted for 5x7); if not, I'll use it on 4x5, which I'm just getting into. Anyway, the glass is pristine, although there is some balsam separation on the far edges. It's been sitting on a shelf in my darkroom waiting for me to test the speeds ever since I cleaned the shutter a year ago. I tested the speeds this past weekend with my simple electronic tester, and was pleased to see that the shutter's 1/50 setting consistently fired within an acceptable tolerance range between 1/47 - 1/55. Once in a while it would creep down to 1/42 or up to 1/57, but there were no crazy outliers. The slower settings are a different story, and I'd probably need to have the shutter professionally CLA'd to use those speeds. But at least I can count on 1/50. As for the masonite board, I know it can chip, but I don't plan to use this lens very often; or if I end up loving it, I'll re-make another board for it in Mahogany.

Now, as far as shutter speed testers are concerned, mine is very simple. I don't like assuming something is accurate unless I have a way of calibrating it with another tool known to be accurate, or benchmarking it in some other fashion. But I haven't been able to think of a way of testing it, so I've just made-do for now. So here's a question: does anyone know of a way of testing or calibrating a shutter speed tester to gauge how accurate it is, using something available to the layperson? In other words, I'm talking about something someone could do at home as opposed to using equipment they might have access to through an industrial shop or optical lab.

Edited to add the frequency distribution of tested shutter speeds at 1/50.

Thanks.

188692. 188693. 188695. 188694

Jim Jones
12-Mar-2019, 11:41
Long ago a phonograph turntable with a white radial line was one way to test between-the-lens shutters. The turntable accuracy can be checked by counting the revolutions in a minute. Using this turntable test can be inaccurate with focal plane shutters. In the pre-digital age I sometimes used the image on a TV screen for a quick rough test. Using an known accurate audio signal generator and step-up transformer to light a neon or other gas discharge lamp also works if you have a means of recording and counting the number of light pulses the shutter passes. The best way remains an oscilloscope, which can also check the flash sync delay.

malexand
13-Mar-2019, 08:08
I just purchased a used commercial shutter tester - still in transit from a less popular auction site, but was thinking about the same calibration issues. My plan was to use my modern 35mm SLR and DSLRs. If they matched reasonably well, I'd call it good.
As for lens boards, I've been making mine out of high quality baltic birch plywood - for a nicer look I can get cherry (or other hardwood) veneered.

Jim Galli
13-Mar-2019, 09:02
A reality check of sorts with apologies. The 17 will undoubtedly cover 8X10 and produce an interesting enough signature. But wide open it will already be at f18 and stopped down a bit you'll arrive at f32 - f45 rather quickly. With everyday film you'll never get to use your 1/50th. In fact you could use a top hat quite as effectively as all the testing. But again, apologies, and carry on. Would love to see some pictures made.

Mike in NY
13-Mar-2019, 09:14
Jim, thank you; you're right about the 1/50th at the 17" setting (actually, its f/22 wide open at 17 inches!). I should have paid better attention to the three-tiered aperture scale; this is the first reversible I've worked with. Perhaps I'll be able to use it when shooting the 8" configuration on my 4x5 with a shallow depth of field, since the lens would be at f/11 wide open.

Can you educate me on the use of the top hat?

Jim Galli
13-Mar-2019, 09:26
Jim, thank you; you're right about the 1/50th. Can you educate me on the use of the top hat?

Place a good black felt hat over the lens. Open the shutter in B. Move the hat out of the light path. Say One ansel adams, two ansel adams, 3 ansel adams, stop and replace the felt hat at the "stop" Close the shutter, and so on. ;~'))

Jim Galli
13-Mar-2019, 09:30
Also, I'm infamous for this (https://www.photrio.com/forum/threads/the-jim-galli-shutter-for-barrel-lenses-drum-roll-please.13953/) bit of nonsense, and this (https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwjsp_XUxP_gAhUQip4KHc0bAoAQwqsBMAB6BAgGEAQ&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DICLG3HCDlhk&usg=AOvVaw1PXirT7OMr4ikNRlyg1mDW). Very best regards.

Mike in NY
13-Mar-2019, 10:04
LOL, I thought you meant there was some way of testing it with a top hat lens board, and I was racking my brain trying to figure out how one would do that!

In New York, we say one-Mississippi, two-Mississippi... except I talk a little slower than most New Yorkers, so I have to abbreviate it to one-Mississip, two-Mississip.

BTW, those full plate holders I bought from you a few years ago are being put to good use.

Mike in NY
13-Mar-2019, 10:21
Jim and Max, thank you both for the tips.