Mamiya 7 80mm Lens: Bent Filter Ring and Sand in the Focus Helicoid
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
This Mamiya 7 80mm lens came into the shop with a badly damaged front filter ring and stuck focus. Not only was the filter ring deeply bent, but the name ring was also damaged. Obviously it took a hard fall at some point.
While I can usually straighten out dented filter rings with my dropping tools, this was a bit more than practical and I chose to replace the filter and the name ring with new parts. Photo five shows the old damaged parts with the new replacements.
The focus issue was caused by quite a bit of sand in the focus helicals. Photos six and seven show what happens when you take your camera to the beach. This particular camera and lens set belongs to a college on the Pacific Ocean so students may not be as careful with the equipment as a private owner might be when taking photos at the sea shore.
The solution to the sand is a complete disassembly of the focus helicals to remove the sand and re-lubricate. The second to last photo shows one of the final steps in reassembly and that is adjusting focus. After focus is adjusted, the rangefinder cam on the lens gets calibrated. Final photo is of the much happier lens.
