more than 50% of the tele-rolleis on ebay have lens separation. It is a comon trait.
Many 2.8 planars have it. It’s simply how they are made, with lenses 1 and 2 being glued together with glue that is now 50-70 years old.
simply put, 100% of the tele rolleis and 2.8 planars will end up with separation somewhere in time, at least those that used canadian balsam. The difference in time is due to the environment/climate of where these cameras have been used and stored.
Look at the lens’ constructions of the Planars vs Xenotar. The planar have glued front elements while the Xenotar doesn’t. Basically, on top of being excellent optics, on par or above the planar (in no case inferior!), the Xenotar is bulletproof as far as lens separation is in question. It simply cannot separate.
The sensible recomendation to anyone in the market for a 2.8 is to avoid the planar when there’s a xenotar right next to it.
—-
if you don’t believe me, do this test: you get 5 minutes to find a planar with separation on ebay.
For the Xenotar, good luck finding one in a decade. They are rare!
——-
here is an interesting discussion onthe topic that I have just found. It highlights the Planar propensity to separation.
https://www.photrio.com/forum/threads/lens-separation-on-rolleiflex.147659/