I'm thinking about picking up a Jupiter-9 85/2 for use with my NEX-6. It will give me a longer portrait lens, which is not something I've used much, but also an 85/1.4 equivalent with my Speed Booster (assuming I can use an M42>C/Y adapter to mount the lens on my C/Y>NEX booster). Any thoughts on this lens? It's not pricey, at $150ish, but not dirt cheap either, so I figured I'd ask for some first hand feedback. Tried to search it but came up empty. Thanks!