Mamiya 7 50mm Lens: Disassembly Tips to Avoid Damage
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
I’ve seen several Mamiya 6/7 lenses damaged a bit from repair attempts. These are not the ideal lenses to begin repair work on if you don’t have experience.
In this post I will go over a couple of issues that I see and how to avoid them. While this is on the 50mm lens for the Mamiya 7, the other lenses are quite similar and need the same careful attention during disassembly.
The name rings on these lenses can be quite tight. The technique is to have the correct rubber removal tool. The ones that I use are factory Mamiya, but I suppose you could find something similar. They are made from a soft white rubber with a concave surface to avoid rubbing on the front lens element. Sometimes this is not enough to loosen the ring and I use a dry film lubricant to help things along.
The first video shows the application of the lubricant and then turning the lens around so that it penetrates the ring completely. Then, take a little rest and allow the volatile carrier to evaporate and leave the lubricant behind on the threads. After this, the rubber tool should spin off the ring easily.
Next, to remove the front filter ring the screws should be lightly tapped and this will loosen any thread lock and also form the screwdriver tip into the screw head. These screws can be very tight and can easily get damaged without this technique. The rear mount screws are also very tight and easily damaged.
The last video shows the tool that I use to remove the rear element. I use this purpose made tool as using an adjustable spanner wrench here can be risky. I recently had a 43mm in the shop that had chewed up retaining rings and a scratched rear element because of previous careless tool technique.
I’d recommend lots of practice on other lenses before diving into the costly (and sometimes challenging without the correct tools) lenses of the Mamiya 6/7 rangefinder system.
