Hi, Bob, I'd be happy to use those 170mm at least. Seems to behave like any modern single-coated Tessar type. Very similar, probably just a little bit tighter, to a 150mm Xenar in coverage, behaviour and look: Excellent in the middle, still very good at the edges even wide open. All of this is somewhat conjecture anyway, right? YMMV. I've not been overly scientific about it, apologies, just reporting first impressions and making the comment that it is indeed fine for general 4x5" use, if you like the look, and don't need great movements, or e.g. Sironar-S awesomeness. I like it, but I'm not sure if l'll keep it long term; I like not having too much gear as I seem to move a fair bit and usually just own 6 or 7 LF lenses at any one time (Jim Galli, Chris Perez and others will laugh :) ) but as I mostly do 5x7" with the occasional a 617 Canham back shoot, I may actually pass this one on soon-ish anyway; it was a nice surprise though.