Mamiya 7 80mm Lenses: Separation and Fungus in the Rear Group
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
I have had two Mamiya 7 80mm lenses in for service this week and was unable to fully resolve the issues with them. Reason: separation and fungus on the rear cemented group. While some of the fungus was cleanable, damage to the cemented pair was not fixable. I have seen a number of these 80mm lenses with the same type of damage and they seem to be from the early batches of production. The photo of the two lenses in this post show similar fungus on the cemented pair and these lenses were produced within seven months of each other (Aug 1995 and February 1996). Maybe this was a production/environmental issue at Mamiya?
Most of these issues seem to be from early lenses. Mamiya began production around June of 1995 on the Mamiya 7 and the lenses that I often see with this issue were produced from 1995-1996 typically but the date could extend further as I have seen a fairly small sample. If looking to purchase an 80mm Mamiya 7 lens, I think I would prefer one produced maybe late 1990s or 21st Century.
