Rapid Omega 100 infinity adjustment

[OAPOli]

New to me camera, with 90mm and 58mm lenses. Not tested with film yet. Checked the lenses with a pseudo autocollimator (85mm f/2 lens on live view, glass plate on film plane) and found the lens board needed to be recessed a bit further to reach infinity.

I found there were 3 (!!) stops to limit the focusing movement. 1) behind the screw on the name plate; 2) on the focus knob; 3) set screw under the leatherette, bottom right. I adjusted all three but something is still preventing the lens board to go deeper. It's somewhere under the bottom section of the lens mount: for the final little bit of movement the upper part of the board tilts rearwards but the bottom stays put.

Wondering what is preventing the movement?

 

[OAPOli]

Answering my own post. I think the issue was that the lens board/tube piece was tilted to begin with.

Next to the infinity screw under the name plate is where the tube assembly is attached to the focusing rack via four screws. Repair manual states that one must shim the attachment to fix the tilt. Of course they didn't make it easy: there are two pressed pins preventing you to easily swap the shim. I made a short shim and slid it under the rear screws (tilt was like this - / -).

Tried a few thicknesses and checked for parallelism and length with calipers. It looks OK but I should get a gauge stand. Still some issues with the focusing but I'll check with film.

 

[ic-racer]

Moving the lensboard back? Make sure you have the specs for that camera. There is a current thread on optimum focal point for 120 film (may not be at the level of the pressure plate.)

 

[OAPOli]

Moving the lensboard back? Make sure you have the specs for that camera. There is a current thread on optimum focal point for 120 film (may not be at the level of the pressure plate.)

Yes I was trying to move the board back but something was preventing it. I have the specs (66.8mm) but without a gauge stand it's a tricky measurement. I started that other thread: repair manual states that focal point is at 66.6mm. I adjusted the camera to the best of my abilities and tested the focus. I think it's good enough?

While on the topic of servicing the Koni-Omega. The film back was giving me a bit of grief: it was sometimes failing to pull film and the frame counter was sometimes skipping a frame. I rebuilt the clutch following an online guide. The old grease was very stiff. For the counter skip, see below (picture courtesy of flickr).

Claw on plunger pushes on the tooth (blue) to increment the frame counter. The plunger has a bit of play and would sometimes ride a bit high, allowing the claw to catch the next tooth instead. I removed the screw assemblies in red. The right one is accessible after removing the cover and leaf spring under the take up spool. The washers with two holes are threaded and have a guide post under for the plunger slot, and the posts have flats. When I reassembled the posts I located the flats on the side to reduce the amount of play.

 

[ic-racer]

I really like press cameras. I hope you get it working and focusing. Have you tested the focus with film yet?

 

[OAPOli]

I did! (see here). Looks like there are RF issues depending on the lens but I'm tempted to call it "good enough".

 

[ic-racer]

Those look pretty darn good for finiky 120 and an old camera. I'd be happy.

 

[OAPOli]

Yes. Since I mostly shoot handheld and outdoors it should be within operator error.

At any rate, I find it difficult to adjust a RF for close distances, due to parallax. If you have adjacent vertical lines within the RF patch they will register at different distances despite being in the same plane.