Mamiya RB67 Pro SD focusing

[djwmasbad]

Hello, all,

This is my first post. I had a Mamiya RB67 Pro S for a few years. The mirror started having problems resetting and I planned on sending it away for repair. However, before I did, I came across a "new old stock" RB67 Pro SD, and thought why don't I just have a fresh start. The SD arrived about two days ago. There was extremely light wear, small dings/chips/rubs, that indicate it is not true "new old stock," which I plan to discuss with the seller. Nevertheless, it is still quite mint, so I won't be returning. My question has to do with the focusing mechanisms of the camera. On my older Pro S, the focusing knobs were very slow to turn. It was sometimes a bit annoying, but it allowed generously for fine focusing. I assumed this was how it was designed to function. My new Pro SD is quite the opposite, seemingly extremely loose in comparison. I can put my hand on the front standard (if that's what it can be called) at full bellows extension and push it back to zero position with just a touch of resistance. There isn't anything particularly wrong with this as far as handling is concerned, but it is a stark and surprising contrast to the tar and molasses of my Pro S focusing knobs. Is this how it is supposed to be, how the cameras were when they were new? Or is this something that warrants an adjustment?


Thanks in advance for your responses,
Daniel

 

[chassis]

Welcome Daniel!

There is some variation in the friction mechanisms of these cameras. For example the ease to turn the revolving adapter and as you mention the focus mechanism.

I have an older Pro S where the focus friction is what I consider "typical", but the revolving adapter has always been like "tar" as you say.

Recently I added a Pro SD and the revolving adapter is nice and smooth, but the focus has a heavier feel.

My point is there is some variation.

What happens if you point the camera + lens assembly vertically down (lens toward the floor) or vertically up? If the standard doesn't move then it's probably in the range of normal.

Even if it does move with the test above, you have the option of using focus lock on the left knob.

Run a roll of film through it with the camera on a tripod and a shutter speed faster than 1/125. Be very critical about your focusing. If the negatives are consistently sharp there is probably nothing mechanically wrong.

Paul Ron on this site can comment better than I can about whether focus friction can be adjusted.

Good luck and keep posting!

 

[jvo]

welcome to apug...

 

[tedr1]

There is a service manual for the ProS online free, possibly here http://www.butkus.org/chinon/index.html

If I understand the manual correctly it shows adjustment of focus shaft torque using the very small screw that is located on the right hand focus shaft bush (in front of the shutter crank) the forward facing screw is the one to adjust.

 

[paul ron]

lose isn't bad, leave it alone, you will get use to it soon enough.

Most people complain the revolving backs are too stiff n focusing is tight.
as long as it cranks the front standard out evenly and isn't wobbling is what matters more.

 

[film_man]

I could push/pull the lens on my SD fairly easily. Overall I'd think that these things get stiff over time as lubricants dry up and leak/evaporate/get pushed out via use.

 

[shutterfinger]

Pro S repair/service manual: http://rb67.helluin.org/files/2010/02/Mamiya-RB67-Pro-S-Repair-Manual.pdf
Likely no major differences between the Pro S and Pro SD.
With lens mounted and at infinity point the camera 90° down, focus position should hold with focus lock set.
Focusing adjustment paragraph 6-2 manual page 18, pdf page 27.
Instruction manual: http://www.mamiyaleaf.com/assets/files/documentation/RB67_Pro_SD_v7.pdf

 

[djwmasbad]

Thank you all for your replies! I'm relieved now. The standard doesn't move or fall when I point the camera down, nor does it when I point the camera up, so it's just something I need to grow accustomed to.