Mounting a lens on a Gowlandflex

[feppe]

I think making the lens board is the easy part...

[feppe]

Any idea how I could remove the lens board from the Heliar lens/shutter assembly? Pictured below, it is the square metal piece, along with the silver ring attached to it. It rotates freely, and there are no screws that are clearly keeping it in place.

There's not enough room in the existing lens board hole to bring the Heliar lens assembly into place from the rear, so I would have to remove the lens board to figure out what my options are going forward.

An alternative solution I considered is to just mount the lens as is (below) to the front of the existing lens board, and it would work. The only "minor" issue is that it brings the image plane too forward, so I wouldn't be able to focus at ranges I need to (3-5 meters).

Heliar lens:
Attachment 84971

Gowlandflex without a taking lens:

[feppe]

I finally figured out at an always helpful local camera shop that there was a retaining ring in a deep recess, which I was able to unscrew without a spanner wrench, which didn't reach deep enough. The lens was then separated from the lens board (pictured on the left). I did the same with my old lens (middle) with a spanner wrench, and now I have a round aluminum lens board which fits the Gowlandflex (right). It mounts to the camera using threads on the outside edge of the lens board, and the lens itself is held in place only by the retaining ring.

The only problem is that the board doesn't fit the Heliar - it has slightly wider barrel. I've been to two metal shops, and they can't widen the hole because they don't have big enough of a drill bit (!), and they didn't warm up to the idea of grinding it. Using some kind of grinder on my drill appears to be ill-advised on aluminum. Something about explosions and fire Looks like I'll have to widen it by filing it away with a metal file.

Fortunately it doesn't have to be exact, as no threading is needed on the inside edge of the lens board. So I should be ok as long as I file the hole large enough to fit the Heliar, but small enough so there are no light leaks around the retaining ring.

You probably knew all this already, but I'm recording this for posterity for those working on Gowlandflexes in the future.

Anything I'm missing? Does anyone have experience with filing 2mm thick aluminum lens board; the widening needed is 2-3mm? Will I be spending a whole day on this? Any tips?

[cowanw]

If you can get something like this
http://www.globalindustrial.ca/p/too...FUNgMgodyAkADw
You can enlarge the hole carefully

[Gundlach]

This is a simple job for a machine shop, all that is required is a milling machine and a rotary table or mounted on a lathe and bored.

[Gundlach]

Aluminum does not grind well because it clogs the grinding stone immediately as the metal is so soft.

[feppe]

This is a simple job for a machine shop, all that is required is a milling machine and a rotary table or mounted on a lathe and bored.

That's what I figured as well, but I got blank stares at two shops.

[feppe]

Took about an hour with a file. Lens fit perfectly on the lens board, and so did the board on the camera. Eyeballing focus on the rear screen seemed to be spot on.

Tested with instant film, and had some atrocious light leaks. Took a few shots, until I noticed there was a screw hole on the board the lens board mounts to - probably to hold the original lens in place. Covered with gaffer tape on both sides, and the polaroids looked great and in focus, aligned with the viewing lens. Whew.

PC port is a bit temperamental as I have to push gently down on it for it to work, but when it fires it does so on time.

Studio tests tomorrow!

[feppe]

Studio shoot went well. PC port kept being flaky, thankfully my lights didn't break and I didn't get a single bad exposure due to it. I'll have it checked as part of a CLA.

I developed the slides, and they look great Dropping off the keepers to be drum scanned later.

Here detached lens, modified lens board, and retaining ring.


And the Heliar attached to Gowlandflex:

[Otto Seaman]

That little Arcatech head is awfully cute underneath that monster... reminds me of Atlas lifting the world.

You need a better camera technician, it may be worth to send it out of the country. Even the most expensive US repair person wouldn't be close to those prices and they would do it right.