I bought this MACROBEL from Spiratone bellows kit cheap online.
There was a lens in the box with it, Vivitar f:1.7 / 50mm, in m42 screw mount.
It all cleaned up nicely.
With a T Mount adapter for Pentax K Mount, I hooked it up to a Pentax K10 D body and looked around the house and yard for small objects for a test, super closeups.
Lighting was from a pair of 60 watt bulbs in desk lamp fixtures. Camera was set to ASA 800, and lens to f:16.