New to FSU - occasional capping or shutter stuck?

[Kingsly]

Hi all! Big thanks to these forums for all the info that got me through a major CLA of my new (to me) FED-2/J-3 combo. 🙂

I just burned through a test roll to work out any bugs, and while it's 90% great - I LOVE this lens - there are still a handful of issues:


During the CLA I did uncover a sticky second curtain - I had lowered the curtain tension on both curtains to get rid of some nasty 2nd curtain shutter bounce, and in speed testing (using a 5D in bulb mode) all speeds are a tad slower than advertised. After painting some naphtha and then lube onto the roller axles the stickiness seemed to go away.
However: On three of the frames the right ~1/4th of the image is black. All the other exposures, as well as the other 3/4ths of the affected ones, agree with my metering expectations. Two of the affected frames are def. at 1/500th. The third is, I think, 1/250 if I remember correctly.


The J-3 seems to focus a tad closer than the RF at close and mid range distances. Other times its spot on. This is odd because I shimmed for infinity and tested with a ground glass and loupe and found it to be accurate at 1m and infinity. The amount of front focusing is consistent, so I think the lens. Or I'm just very consistent in my lack of technique... 😱

One thing I can say for sure is the FSU bug has bitten me BAD!
Cheers!

 

[PRJ]

Did you really clean the snot out of it before you relubed it?

I have a Zorki 5 that I redid about 12 years ago. I completely dismantled it. Every screw. IIRC it was packed with Yak poop. Terrible stuff! I put new curtains in it and underwound the shutter because I thought having 1/15 is better than 1/500. Basically all the shutter speeds are halved. It still purrs like a kitten. My point is if you didn't get it completely clean, it won't work well. If the shutter is capping then one spring has more tension or there is something holding a curtain back. If you want it to work perfectly, it needs to come apart completely and put back together with modern synthetic lubes.

If the lens is out, and you say it is on according to your method of checking, then you need to check your method of checking.. What kind of ground glass did you use? The problem probably lies there.

Hope that helps.

 

[Ko.Fe.]

CLA means Cleaning, Lubricating and Adjusting.
Dumping naphtha into has absolutely nothing to do with cleaning.

Dumping into the naphtha absolutely disassembled parts of the shutter is the cleaning. You have to hold each of the spring in your hands and dump it to the naphtha. And if it is not done this way, all of your questions and tests are totally irrelevant.

It is easy with FED-2. Here is no extra parts like in FED-3 and later. FED-2 is like Zorki with timer.

 

[wolves3012]

What's been said above is right, if you didnt dismantle the parts and clean them it's not really a CLA. I know that sounds a bit harsh but it's true. If you put a solvent onto the roller pivots, plus lube, you'll probably improve things only until the solvent has evaporated fully (however slowly that might be).

Partially black frames means the two curtains have met and there's no travelling slit - it's called capping. It tends to happen at higher speeds and could be caused by too slow a first-curtain or too fast a second-curtain. With a shutter that's not thoroughly clean that usually means the former.

With a properly cleaned and lubricated shutter it's actually quite difficult to tension the rollers so badly that capping occurs, although "tapering" can happen - that's where the exposure is uneven due to a closing-up or opening-up slit-width. However, when I messed about with shutter tensions (for experiment, with a freshly CLAd shutter), I found that even tapering needed a deliberate and clearly wrong tension. If they're properly cleaned and lubricated, these shutters just want to run right.

EDIT: I forgot to say: don't bother trying to get the shutter speeds exact, it just won't happen. If you can get them reasonably close it'll be plenty good enough for the real world! Not sure whether you have an early or later FED 2 but if the 1/25th or 1/30th (whichever it has) is about right, you'll have to live with the other speeds as they are.

As for the focussing, I've never used a J-3 but the lens is a Sonnar design and I have heard of the "Sonnar shift", which is an aperture-related shift in focus point. Might you be experiencing this or might it be upsetting your technique? Something to investigate.

 

[Kingsly]

Thanks everyone.
I disassembled and thoroughly cleaned the camera internals, relubing with greases and oils (depending on the part), but I stopped short of removing the shutter box itself. The curtains are in very good condition and I figured I'd rather burn a test roll - since it otherwise in days worth of testing and firing at all speeds seemed to be operating reliably - than pull them apart and risk damage. Heck, I even set up my digital cinema camera and filmed tons of hi-speed (240fps) tests of the shutter curtains at all speed settings!

Obviously if it's capping every once and a while something is gumming up in the rollers. It's coming apart again anyway so I can service the beam splitter (bad balsam separation) so I'll pull the shutter crate.

My questions for the pros:

When pulling out the crate, is there latent tension in the rollers (obviously firing the shutter as the first step)? Do I need to completely remove tension first using the adjuster screws?

Does the assembly want to pop apart or does it just drop out of the camera as a unit? Mentally preparing here...

I'd rather not remove the curtains from the rollers - am I out of luck at this point?


As for the lens, I used a focusing screen laid flat against the film plane... The lens needed .20mm of shims - cut from the same shim stock we use on cine lenses - to hit infinity. I tested close focus w/ a Siemens star exactly 1m away from the film plane. Satisfied w/ the results I tested a few random distances getting the rangefinder sharp and then checking the projected image of the lens. Granted, there's only so much detail to be seen w/ a loupe, I suppose what looked sharp to the eye could have been front focused a bit. Is it possible that it's hitting infinity and wrong at 1m or are the focus barrels/hard stops reliably calibrated? If forced to choose I'd rather sacrifice infinity for reliable focusing at portrait distances...

 

[Ko.Fe.]

You don't have to remove curtains from the rollers. Inner part of rollers is usually not this dirty and not so critical. You'll see the most of gunk on the springs.

Take as many pictures as possible during assembly. Put some non removable marks on connected parts before taking pictures.

I put it back with slightly pre-tensioned springs. Taking out, doesn't matter, IMO.
For shutter service and putting it back use Fedka pages for Zorki as reference. Shutter and top under the top plate are the same.



To calibrate FSU RF lenses I'm doing it on one meter, wide open. If lens is with original parts it is fine on infinity. If lens doesn't reach infinity (and all parts are original) it is wrong heliciod assembly.

 

[Kingsly]

Good to know!

I'm actually not entirely sure how the springs are assembled - this whole time I've been picturing them constructed somewhat like the motion picture cameras I've worked on, with a wide flat mainspring inside the hollow roller? But now that I think about it...


As far as I can tell the J-3 had never been apart. The issue with infinity was that it would focus slightly past it when hitting the hard stop. I'll concentrate on nailing 1m focus. It's also worth mentioning before tearing into the lens I measured the camera's flange distance against a ground glass taped to the film plane and found it to be exactly 28.8mm. So at least we're starting from good place!

 

[mburns]

After your calibration, you are probably seeing the intrinsic inaccuracy of a rangefinder at intermediate distances. I have measured this before on my rangefinders.