Attempting to Replace Lens on Gowlandflex, Don't Know What I Need

[Don Dudenbostel]

The best solution but most expensive is to send your viewing lens to Schneider / Century Optical in California. They can measure your existing lens specs / FL and hand pick a matching new lens. Very good people to work with.

Second choice, KEH has a ton of Symmar S 210mm lenses. Order one and try it. If it's off order another and return the first. Explain what you're doing and keep trying. You might get one close enough for a couple hundred dollars. KEH has a very good return policy. At the most you're out a little postage.

It's true that the FL of each lens is slightly different but they may be close enough at the distance you'll be shooting.

[JosephBurke]

For what it's worth I wondered how exact the focus was calibrated (by Peter Gowland) was/is on my early 4x5 Gowlandflex. Since you can focus on both the top GG and the GG at the film plane they appeared reasonably spot on visually. In actual testing, if you call it that, with film (polaroid) with the lens wide open and a ruler at a 45 degree angle the focus on the GG up top and the resulting image confirmed that it is just that--spot on.
Regarding parallax correction, both my early model and the later version I have both have this feature.

[JosephBurke]

For the original poster, I think I would just find a Chrome rim 210 5,6 Symmar like Peter Gowland used in a Compur shutter, mount it, and do a similar test. That should do the trick.

[jbhalper]

Just coming back to update:

I bought a Symmar-S 210mm Lens with a Copal 1 shutter. Perfect fit for the lens board taking position.

Mounted the lens, had no problems getting a focus, but major problems getting it in sync with the viewing lens initially. There was about a 1cm difference.

Removed some felt added to the graflok back that looked legitimate, but confirmed that this brought everything closer together. Found that the bump on the original lens board in the picture was the remaining difference. I created a test lens board out of thick card-stock, without the bend or the bump and then both lenses came into focus simultaneously.

I found a local metal shop to copy my existing lens-board to an identical version without the bend or bump, and have installed everything with excellent results.

I'm fine-tuning things now, and may need to shim things up, and possibly to put that bend back in the board for some parallax correction, but I'm not sure that matters a lot. There's a clever sliding frame beneath the viewing glass that outlines the part of the frame which will be in use on the taking glass, and since I can see both, I'm confirming that it's pretty accurate as-is already.

Thanks again to everyone for the help. I'm quite close to a nicely functioning and restored Gowlandflex, and while it had a nice story before it was working, I'm happy to have a little more story of my own to add to it. Just going to test things out, possibly shim a lens, and then clean it up a bit.

[pierre506]

Congratulations～

[Steve Smith]

Since you can focus on both the top GG and the GG at the film plane they appeared reasonably spot on visually.

If you can do that, it would be easy to shim one of the lenses to make them match. If this was mine, I would just get a lens and try it then see where to go from there.


Steve.