Upload & Sell: Off
Thanks to recent lens acquisitions, I've got the chance to try out the Leica Elmarit-R 135/2.8 and Zeiss Contax Sonnar 135/2.8 side-by-side. For anyone who is interested, I'll be sharing my results in this thread.
To begin, here are the two contenders:
The Leica is the "second version" (designed ~1968, my copy from ~1974) of the Elmarit-R. The Contax is an AEJ version, with a "ninja star" aperture at f4. Both lenses are very similar in weight, with the Leica feeling a bit more dense in the hand.
Build quality is highly admirable on both, and would be familiar to anyone who has used similar-era Leica R or Contax lenses. Both have engraved focus scales, "clicky" aperture rings (in 1/2 stops on the Leica, full stops on Zeiss), and ~240° of turn to go from infinity to MFD (1.5m for Leica, 1.6 for Zeiss). Both have 55mm filter threads and similarly-sized pull-out hoods (common for Leica R, unusual for a Zeiss Contax lens).
The focus ring on Leica has a light touch; while moving, it is buttery smooth and near silent. However, the Leica focus ring has an issue that I have observed in other Leica lenses from the same era, which is a tiny hint of binding whenever you first start moving the lens. This makes fine adjustment tweaks of the focus difficult, because the focus ring tends to start with a tiny "jump" as you overcome the initial friction. I think this is the result of "too precise" helical manufacturing --- the focus mechanism is very tightly coupled together, with no gaps/slop between the threads.
Zeiss has made different design choices for their focus ring. The focus is a bit more damped, and with a hissing feel and sound as if sliding two pieces of paper together. There is no starting stick, so the focus ring can be turned very finely. However, this is at the expense of a tiny amount of backlash: whenever you reverse the focusing direction, you can feel a slight "hiccup" a tiny fraction of a turn later, as the helical shifts from pushing on one side of the threads to the other. This is a tradeoff, adding a little "slop" to the focus, against the potential "stickiness" of Leica's near-backlash-free more tightly matched helical.
More to come later.