Over the years I have build up an extensive collection of Pentax SMC (first bajonet mount) lenses, Pentax F lenses, Pentax FA Limited lenses and Hexanons. I am very pleased with them and with the camera's as well. But every once in a while I read or hear a raving review about Leica R lenses. The general consensus seems to be that the R camera's are decent, but the R lenses are truly spectacular. Perhaps overpriced, but nevertheless spectacular.
Never ever had any experience with Leica, I sometimes wonder .... what am I missing?
Does someone with first hand knowledge has any thoughts to share?
I work with both the Leica R system and the Contax (Kyocera/Yashica) Zeiss lenses. We share some of these (but we don't advertise this lol) in our public darkroom so I can offer some student feedback.
Perhaps the German optics is what you may be missing out on since the glass which you've described using is Japanese (mostly Hoya) glass; whether it's specifically Leica R glass is another level.
Both Contax S2/S2b manual cameras and the Leica R6.2 are well beyond mere 'decent' cameras. Nothing in the Pentax chassis stable other than the LX will come close to either. We still keep a Pentax Spotmatic for the students and they are always amazed at the Takumar SMCs and the poetic images which the Pentax lenses bring out. Only one of our students has touched a Leica R6.2 with a 80mm Summilux f1.4 lens for her A level college portfolio and was stunned by it. She was fortunate to get a hold of it when one of our battery operated SLRs packed up despite new batteries, needing a mid-roll film change. The R6.2 was rather heavy for her hands and she preferred the smaller Contax cameras like the S2 and the Aria eventually. Other photographers just use the Spotmatic with standard 50/1.7 and the 1970s solidity is a pleasing balance however amazing the Leica R6.2 feels. I don't care for anything automated and thus we have a very limited range of battery dependent cameras. Dampening of the Leica lenses; the build, the weight all feel hefty and substantially superior to the Contax Zeiss build which is outstanding for the students compared to the Pentax glass and rather worn barrels.
Overall, the myth around the Leica brand perhaps is unhelpful; particularly for film photographers discovering Leica R glass way too late in this current climate. I still use the Leica R system for its lenses - particularly 2 lenses: the Leica Elmarit-R 19mm f2.8 (v1 or v2) and the Summicron-R 35mm f2.0 (v1 & v2) - both are peerless lenses. Everything about them - build; its size, its form factor, its optics and its rendering. It's just enough to melt for.
As an SLR comparson, the Contax C/Y Zeiss Distagon 21/2.8 is optically brilliant but completely of the wrong ergonomics and rather unbearable as a regular lens to carry. I relinquished my 21/2.8 and settled for the Leica R 19/2.8 which is less than half the length of the Zeiss. The cost of the 19/2.8 now isn't really worth considering for a film photographer ~ that boat has sailed and if you're not on it, it's probably worth learning to forget. Similarly - the Summicron 35mm f2.0 has such a fantastic focus shift (on SLR this is visible; on rangefinder it is appalling to work with) across the field effect as a landscape lens. The size of the lens is similar to a Contax C/Y 35/2.8 for the extra stop which is indispensible. Whereas the Contax C/Y 35/2.8 was designed as a lightweight mountaineering friendly lens, its plastic barrel suffers significantly over the decades beyond its market intended use. The Leica Summicron 35/2 has such a robust construction it's no surprise to see these distinctive lenses retain their appeal.
When it comes to the 50mm Summicron-Rs and 50mm Summilux-R lenses, I can't say I notice anything outstanding about these Leica R lenses. The Zeiss Planar 50/1.4 and 50/1.7 perhaps I prefer for their stronger contrast and T* coating. The Leica Elmarit-R 60/2.8 shares the same outstanding field correction and incredible MTF and real life usage as the Zeiss 60/2.8. For the 85mm short portrait lens comparison, the Leica Summilux-R is shorter at 80mm f1.4 compared to the Contax Zeiss C/Y 85/1.4. Neither are 'better' than the other. The Leica 80/1.4 unfortunately happens to cost about 4x more than the Contax 85/1.4. Leica R 135mm lenses are prone to delamination (don't ask why - but the problem comes up disproportionately more) for their age. The Apo- versions of the longer 100mm+ Leica R lenses are outstanding but harder worth the cost now. Some of their focal lengths, like the 180mm f2.8, outclass the way older designs of the Zeiss Olympia 1970s derived Sonnar 180/2.8.
As a mostly wide-angle photographer, the Leica-R 19mm Elmarit-R f2.8 and the Summicron-R 35/2 lenses are really stunning to the point of feeling excited about film photography all over again. The Leica-R Super Angulon 21/4 was designed by Schneider Kreuznach of Germany, whose optical advances in the ultra-wide angle field is second to none, particularly in large format photography. Its design is easier to use than the Contax C/Y 18/4 lens with its rather unusual front element filter although the lens suffers in most areas compared to the Contax C/Y 21/2.8 Distagon. In terms of semi-fisheyes, the Leica R 15mm f2.8 I've never tried however this is going to be the spectacular lens for denting the wallet. I use the Zeiss Distagon 16/2.8 which is better than a 3rd party wide angle lens or anything from Yashica (Japan) and enough to repel anyone who doesn't enjoy semi-rectilinear imaging. The optical design of the Leica-R 16/2.8 shares the same heritage from Zeiss (or is that the 15mm f3.5?).
The fine points are nothing to fret over in any case. Perhaps try a Contax SLR with a Zeiss lens if you are looking for something different from the Takumars and excellent Hexanons. If not, taking more images with the lenses and looking beyond the labels and manufacturer - which the students who use film in our darkroom do - puts the camera brands into relief.
Kind regards