New Lens

I've just acquired another vintage lens - this time it's a Carl Zeiss Jena Tessar f2.8/50mm. (Thank you for the suggestion J.G.!) On first impressions,  I think this one is going to be a bit more challenging to use than my other two vintage lenses.

This is mainly because:
1) the focusing ring is very stiff - stiff enough to unscrew the lens from the adapter /camera if you're not careful.

2) The thread on the lens/adapter means that all the gauge information is on the underneath of the lens.  This isn't a problem for the F Stop ring as that's fairly obvious and there is a stop down preview switch, but it did cause a few problems initially when trying to gauge focal distances. This wasn't helped by problem number 1. 

Hmm.  Any suggestions gratefully received, particularly for safe/straightforward methods of loosening(?) the focal ring a little. 

Still, it does have some nice bokeh at both ends of focal length and when you can get it focused, it's nice and sharp.  Having said that, I also rather like the unsharp, slightly abstract butterfly shot I've posted as an extra. The main shot is uncropped, slightly sharpened and I've just adjusted the colour balance a little.