Originally posted by RobA_Oz The Tri-Elmar has a very good reputation. I almost envy your combination, there.
Some Leicaphiles look sideways at it... It's slow, no RF has the correct framelines for it*, it isn't particularly sharp at wide settings and you can't use filters on it without an adapter as the front element has pronounced curvature. Also it has a weird distortion characteristic that isn't consistent between focal length settings. On the plus side it's a very convenient lens to have in the bag, and substantially cheaper than the Leica Summilux 21mm f/1.4 ASPH - though I own a copy of that lens too.
Pentax K10D - FA77mm f/1.8 Limited ISO 400 f/5.6 1/100th *an external viewfinder with matching frame-lines does exist, and it's one the most expensive viewfinder accessory I have ever seen and would be exceedingly annoying to replace if you ever have the misfortune to lose it. As well engineered as it is, the
frankenfinder isn't the most aesthetically pleasing piece of kit.