I purchased some none branded Japanese filters for my Bessa R2 / T RF setup (as Hoya / BW items were not easily available new). I found the glass to be OK but the metal rims were much thicker than Hoya / BW which meant the lens hoods would not screw on with a filter fitted. Have since stopped using them after finding some good used Hoya / BW ones on Ebay. If you wait long enough most sizes will turn up on Ebay. Hope this helps.