SK 47mm XL R mount mechanical problem

[espelancer]

I just bought a 47mm XL in R mount, it seems the mount is not well aligned. I want to confirm whether this is how it supposed to be, or there are something wrong with this lens and I should return?

When the lens arrives, I notice that the gap between the board and the mounting ring (not sure what are the correct names) is larger on right side than on the left side. See the circles in the image below.


I tried to unscrew the board, but found that the depth of the recessed board is actually larger than that of the ring. The board cannot seat completely in the ring. I can try to make the gap even when screwing, however the lens board is loose maybe because it doesn't go all the way to the end.


Given that Arca-swiss R cameras are branded for high precision, this doesn't feel right. I want to check is this how it supposed to be?

 

[Alkibiades]

it must be perfectly hanging, without any gap. Try to remont this board by moving it out and mount it for the second time - for this you have marks on the side of the board and the tube- thay have to be exactly on the same possition.

 

[4x5Australian]

Hi espelancer,

Yes, the components are mis-aligned. The R lens board seats down into the R calibration ring (which Arca-Swiss calls the calibration tube, but let's go with ring) and must sit flush.

The R lens board and R calibration ring don't screw together, they bayonet together.

There is a recessed red dot on the outer perimeter of the top surface of the lens board. When mounting the lens board to the calibration ring, the red dot must be aligned to the pair of notches cut into the side of the brass ring, which is a mating plate for the calibration ring. The pair of notches is visible in your first photo, above your thumb.

To fix the present misalignment, first remove the lens board from the calibration ring by rotating the lens board counterclockwise so that the red dot aligns to the pair of machined notches, then lift it up and away from the calibration ring.

Once the two parts are separated, re-attach the lens board and lens to the calibration ring by:

(a) aligning the red dot on the lens board with the two notches on the brass mating plate - and the red dot that is now visible on the upper surface.
(b) seating the lens board properly onto the brass mating plate, and
(c) rotating the lens board clockwise about 2-4cm until it stops.

 

[espelancer]

Thank you guys for the information and especially 4x5Australian for the detailed explanations. However, I cannot get the board into the place as you explained. I feel the board is deformed.

 

[guphotography]

If you think there is a defect, you can try your dealer to send it to arca for service and recalibration.

All the R mount lenses I bought had gone to Arca directly from sellers for check up and service, I've only paid for one that required replacement parts, which was very reasonable. The rest were serviced under warranty.

If there is no dealer involved, I can send you the contact person and email address, top notch service.

 

[4x5Australian]

Perhaps the R lens board has been dropped onto its edge and deformed. However, in your two photographs it appears to be ok.

Instead, perhaps the recessed R lens board mounted to your lens is not the correct one for the 47XL calibration ring.
There are a few different recessed R lens boards for the different short focal length Schneider lenses, and the one attached to your lens may have been interchanged with a different one from another focal length.

This might explain your initial observation that the lens board cannot seat in the calibration ring.

The USA representative for Arca-Swiss is Rod Klukas, located in Tempe, Arizona.
[email protected]

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[espelancer]

I got it from eBay, I don’t think the seller is an Arca Swiss dealer. I didn’t know such thing can happen

 

[4x5Australian]

I got it from eBay, I don’t think the seller is an Arca Swiss dealer. I didn’t know such thing can happen

No, the seller won't be an Arca-Swiss dealer. Such a thing shouldn't happen, but some people don't look closely at what they're doing.

Did the photographs in the eBay listing show the board as it is now, or seated?

Rod Klukas can order you a new R lens board from Arca-Swiss, or he may have another one on hand that he can send you.

Or contact the seller and either sort it out or return it.