Focusing a mamiya k/l lens.how do i use the floating element ring? thank's

I noticed quite a few of the used mamiya 140mm macro lenses have a stuck scale. In this case you would need to get it repaired, or repair it yourself (which is doable but can be annoying, I have done it myself). If you are willing to go with repairing it, you can contact me: hi [at] alexorsholits.art

Normally I would advise against opening up a lens to clean it. You are likely to get more dust in than you get out, and it can be extremely difficult to get the bits back together again. However, if all you want to do is remove the front element, without disturbing the aperture mechanism and complex stuff at the back of the lens, then it is pretty straight-forward.

The front element (probably two or more pieces of glass cemented together) is held in place by a retaining ring that can be unscrewed. Often this ring will have two little slots on opposite sides of the lens with which to grip the ring and unscrew it. You won't have a suitable tool for this around the house, so will have to make or improvise. I have got away with using the points of the blades of a pair of scissors, but take great care, as a single slip will put a scratch across the camera lens that is much more serious than a bit of dirt. Sometimes the ring (at least the outer one, which is merely a cosmetic cover) can be shifted with a jeweller's screwdriver in just one of the slots, pushed around the circumference with your thumb. If it has no slots, you can often grip it with a disk of rubber cut from a bike innertube. This may expose a further, more businesslike retaining ring that actually holds the element in place, which you treat in the same way.

Except that I have been disassembling an old lens as I write this, and while struggling with the second ring, the glass of the front element just fell out and landed on the floor. Apparently the second ring holds something else. Oh, dear. At least it didn't break. I expect I may have disturbed the fine tuning of the focus by shifting the second ring, but I would never do this with a lens that was worth anything.

If you have a lens collimator and other equipment required to ensure the proper alignment of the lens elements when you reassemble the lens, then go for it. If you don't have the gear needed to reassemble the lens properly, then I strongly suggest taking the lens to a good camera shop and have a trained professional do a clean-lube-adjust. It won't do you much good to have a focusing ring that turns if the lens elements are out of alignment so it doesn't focus properly.

You might have an earlier rb pro S ( not pro sd ) version.
The later pro sd lenses have a larger diameter rear element.
The rb67prosd extension yube is clearly marked pro sd the older version just has-
mamiya no.1 45mm.

I googled around and came up with this:

http://photo.net/medium-format-photography-forum/00PND1

You'll find the pdf. file there

bw

SMP

These lenses arn't designed to be taken apart.

A camera specialist may help but they should alwys be kept dry and at room temp never warm and humid. Silicate gel in your storage bag also prevents this from happening.

Good luck

Marc

most likely some of the gears are offline or collapsed. when that happens it gets difficult to turn. you could send it to mamiya for an estimate or to mackcam.com

The lens has a lever marked A/M near the aperture ring. If the lever is in the 'A' position, the lens will stay wide open until you trip the control lever at the back of the lens next to the rear optics. In the 'M' setting, you can see the aperture move as you change the f-stop setting on the ring. Set the lens to anything but wide open and move the control lever with your finger. You should see that aperture move.

Any luck with the lens?
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This will need technical service eventually. Try temporary solution with Sellotape or similar