As allready has been mentioned, you might keep an eye on the K-series as well.
Many if not most of the above mentioned stellar Takumars were transfered from M42 to K-mount.
Also the K-mount version may not resume the mechanical quality of the Takumars it allways lightyears ahead of what most modern lenses show.
The K-mount versions have in general a better version of the SMC multi coating and are sometimes easier to get.
Of the above mentionde Takumars available as K-mount are for example:
15mm / 3.5
17mm / 4.0 Fisheye
55mm / 1.8
85mm / 1.8
125 mm / 2.5 - view test
Pentax SMC-K 135mm f/2.5 - Review / Lab Test Report
Please be aware, that the Takumar lenses often have different optical designs despite having the same designation in focal length and maximal aperture. For example the Auto Takumar 85/1.8 and the Super-Multi-Coated Takumar 85/1.8 (the one mentioned above) are of different optical design. The same is true for the 135mm/2.5.
The later Super-multi-coated and smc variants being the better one from optical design and coating in general.
On the other side there is the 55/1.8 which never changed it's optical design.
I recommend you to have a look at the forum database if you located and object of desire.
Pentax Lenses - Pentax Lens Reviews & Lens Database
---------- Post added 01-24-22 at 03:10 AM ----------
Originally posted by Rbonn thanks......clearly, today's lenses are tremendous on so many levels. But the fun is shooting with something that didn't cost $1000 or more, is 50 years old and still yields really nice results. I"m sure many of us used MF lenses for a long time......it's second nature to me and slows me down. One thing digital, mirrorless cameras with AF lenses speeds me up, way too much.
William Eggleston only took one shot of a scene he saw. Digital is like a semi automatic......keep shooting and you'll hit something.
I love the old stuff for slowing me down.
Many bread and butter Takumars are quite affordable, but expect the sought after not to be cheap. The 135mm/2.5 is still available at reasonable prices but you should not think you can get a 85mm or 17mm for under $300. Try to guess in which price regions you might locate a 15 mm.