Mamiya Press lens problem

[nick dawson]

I've just bought a Mamiya press lens imported from Japan, 65mm, f6.3. The focus ring is almost impossible to turn. Are there any repairs in London. Took it to one in sout london today but they dont have the technicians to cope with 'vintage' lenses.

[orsetto]

You may need to just live with the very stiff focus feel. My experience with four examples over the past decade suggests the helical Mamiya employed in the short 65mm Press lens barrels tends to be extremely stiff and hard to turn. Several very respected camera techs advised me that such incredibly stiff helicals (including the notorious older Hasselblads) are often very difficult to smooth out for a nicer feel. You either learn to work around it, search for an elusive smoother example, or opt for a different / newer lens design. The last is not available for the Press cameras in 65mm focal length: Mamiya unfortunately decided to replace the 65mm with a 50mm and 75mm (both very well regarded, with modern helicals and coatings, but shorter/longer than the ideal compromise 65mm).

Of the four 65mm f/6.3 Sekor examples I've owned, two were extremely stiff to focus (almost immobile), one was annoyingly firm but usable, and one was perfectly smooth and damped. The one with best focus feel had scratched elements and a bad shutter, so I kept looking for a replacement. In retrospect, I should have just bought one donor to harvest glass from and have my tech replace the glass and repair the shutter of that smooth-feel example. But at the time I did not know this lens design tends toward really stiff operation. After importing three replacements from Japanese eBay dealers over a period of five years, I settled on one pristine-looking example with perfect glass. Unfortunately it seems to use gorilla glue as lubricant, so not the most pleasant lens to shoot with. I just stop down as much as possible and use hyperfocal distance settings for most shots, using the the rangefinder only when absolutely necessary.

If you decide to let a tech try to loosen the focus, you might want to ask them to also remove the lens aperture limiter when they take the lens apart. The 65mm f/6.3 Press lens can actually open up to approx f/4.5: Mamiya mechanically prevents this by gluing an easily removed pin on the internal aperture setting ring. They factory-limit the lens to f6.3 to ensure consistent performance wide open, but overriding the limiter gives the option to let in more light for the reflex viewing adapter and/or exploit "dreamy" visual effects (aberrations increase dramatically if the 65mm is opened wider than f/6.3).

 

[David_Shanley]

I know this thread is a little old, but I want to describe my experience with the Mamiya-Sekor Press 65mm f6.3 lens.  Late in 2021, ealy 2022 I bought a gorgeous 65mm F6.3 from Japan on ebay.  When it arrived, the focus was a little stiff, but rapidly became stiffer until it reached the point of "if I could get it back to focus at infinity, I am going to only use it for landscapes anyway".  My repair guy,  who was swamped as usual,  recommended I put a TINY drop of Marvel Mystery Oil on the helical focusing threads that are visible from the back of the lens with the point of a toothpick, and try to work it in by moving the focus.  One drop did not do the job, but one drop each day over the course of a week DID!  If you don't have that brand oil, I would not recommend the usual form of penetrating oil. Marvel oil is  a little thicker than that and takes its time to move around. Hopefully you would have something similar after a search   The focus remained smooth for the next year or so that I used that lens until I sold it and my Mamiya press outfit.

[John Seaman]

I've freed up many stiff focusing 35mm lenses by introducing a little light sewing machine oil on to the helicoid threads where visible. With rangefinder lenses you can often do this without dismantling. With SLR lenses you have to unscrew the rear group.

[neil_grant]

My exprience of vintage 'Press' lenses is similar to that of D_S.  I also recently bought and Mamiya Press lens from Japan - a gorgeous 100mm f/ 2.8 c/w Universal 6x9 camera body. From the start, focusing was rather rough and unplesant to use and then the lens almost seized completely. I encouaged/forced it back to infinity - and then left it like that to contemplate the situation, and check the web for ideas about sorting it out. In the end I was able to re-grease the, almost completely dried out, helicoid 'in situ' - without totally dismantling the lens. I removed the lens's rear baffle plate, revealing the tail end of the helicoid, and then dabbed tiny amounts of 'thin' helicoid grease into it with a fine brush. I left the lens face down for a period of days and then started to gently exercise it - focusing it a little closer and then back to infinity. Now and then i gave it a bit more grease. Eventually, over a period of weeks i was able to get the lens to focus smoothly all the way through it's range from infinity to 1m. I also have a 'Press' 50mm f 6.3 with stiff focusing needing attention - but that should be the subject of another post.

[orsetto]

Thanks to neil_grant for his idea of removing the rear cap, and David_Shanley for the tip re Marvel oil! I replied to your other Mamiya Press 65mm thread with my experience trying to loosen up my own stiff 65mm: results weren't quite as successful as yours, but I didn't have Marvel oil at hand when I tried.

Edited March 29 by orsetto