Originally Posted by wjlapier
I'm in need of some caps for two lenses. I think I saw a rear cap for the Mill 50--I'd like one of those. And I'm in need of front and rear caps for a 3.5cm f/3.5 without the threaded filter ring. Any suggestions on what to look for--where to find? And finally, hopefully, not to expensive!
The only inexpensive source for rear caps for the 5cm & 50mm internal mount Nikkors that I have been able to find are from an eBay seller with the handle of nobbysparrow from Japan. His price is $10.00 per cap and a single flat rate of $3.00 for worldwide shipping. His caps are a pretty good approximation of the Zeiss Ikon #727 cap, but without the felt lining. Moreover, his caps do not mount to the bayonet lugs as does the vintage Nikon "S" cap. Instead, his caps are a friction fit with the back of the lens.
Link to Nobbysparrow's Listing for inexpensive rear caps for the 5cm & 50mm internal mount Nikkors
However, if you want a vintage Nikon "S" rear lens cap, they can be a bit pricey. Although they do occasionally appear on eBay.