A rare Zeiss S-Planar 1.6/50mm lens ...

[kds315*]

here on ebay Click here to see on Ebay which not only makes a fantastic doorstop due to its weight,
but also a very nice conversation piece

Fun aside, it is a 2nd generation chip making lens of very high precision, made for 436nm (deep blue),
very heavy, but since it cant't be stopped down, nor mounted easily, not really a "useful lens".

It's pretty cheap, those sold for $$$$ used not too long ago.

[Orio]

Still curious about what images it would produce with a camera, though.

[kds315*]

I had several of those in different focal lengths, but gave up on them...