Originally posted by edd1388 Without the glass element, there is no degradation, but there is no infinity focus.what does he mean by no infinity focus?should i just find a pentax lens 50mm f1.2 instead?need some advice and opinion..thank[/I]
I say you'd only be able to focus maybe 1 meter or less, because without the glass elements you just add extra space between the lens and the sensor.
I'm not by any means recommending you to do this, but I have modified this lens and use it with my K20D. I removed the FL mount and glued a M42 flange adapter instead. This way I think I've reduced the distance to the sensor for 1 or 1.5 millimeter (FL mount is slightly thicker than the M42 adapter), but this is still not enough to get infinity focus. I can only focus up to 3 meter away. Since you're adding more distance with the hollow adapter, that means even closer max focus distance. 1 meter is just my guess. And 1 meter is not enough for portrait IMO.
So my point is, I don't think using it with glass-less adapter is very useful. Just get an actual Pentax 1.2 or Chinon 1.2