Originally posted by DanielT74 According to read reviews and tests all the Takumar and Pentax 50/1.4's are great, wonderful bokeh, good sharpness and better than nearly all other 50/1.4's because it has a group of 2 elements which on the sides they are glued together are curved while other brands have elements with flat sides glued together here.
I read your comparison with the Summilux (alas no images anymore) which is of quite a later date (introducted 1969, produced 1970) than the Super-Takumar (1964-1971 for 7 element, 1964-1966 for 8 element), especially because the one you included is the older 8-element version which thus also has an element more and thus as a result is more vulnerable to flare. Moreover, in 1971 Pentax introduced the S-M-C version. Leica updated their R-50/1.5 from 2-cam to 3-cam during its lifetime and likely had it updated to multicoating too but I can't find when. Your summilux thus may have been multicoated. Now in 1979 updated their 50/1.4 from series vii filter-size to 55mm filter-size and replacing the clip-on hood for a built-in hood. Some count his as the second version, others still as version 1 as the optics didn't change. Another nice twist is that the next version, thus either called second or third version but it is the last one, which has a 60mm filter size and also features a ROM-chip, like the 'Planar-killer' Super-Takumar has 8 elements in 7 groups.
Now the last Summilux-R being considerably better accordng to Leica fans may qualify for 'the one best' 50mm but generally this title has always gone to the Summicron 50/2.0.