Takumar 50mm
The first Asahi reflex cameras used a 37mm diameter screw lens mount. Then came the Asahi Pentax using M42x1. Several generations of lenses have succeeded: Takumar (diaphragm preselection) then Auto-Takumar (automatic closing of the diaphragm, manual reset), Super-Takumar (automatic diaphragm), Super-multi-coated Takumar (multi-coated lenses) and finally, SMC Takumar (the same in a new bodywork). The coupling device for measuring the light at full aperture did not appear with the Super-Multi-coated Takumar as I've read, but during production of the Super-Takumar, anticipating the release of Electro Spotmatic and Spotmatic F. All our lenses are so equipped (including the 28mm and Macro 100mm)1: diaphragm closure pin2: positioning stop for the coupling device3: diaphragm coupling lever4: lock prohibiting moving into manual position for cameras on which it would distort the metering (grip in the screw holes of the Zenit mount, protect it with a small piece of tape!)
Tests: Please note that these tests were made with the means at hand, not in a "scientific" way. See here.
Super-Takumar 1.8/55mm bought with my Spotmatic II october 30th, 1979.
The lens of my first Pentax. The coating is yellow compared to SMC versions.
SMC Takumar 1.8/55mm bought by Christophe with a Spotmatic II december 21st, 2010.
The next generation, multi-layer coating.
SMC Takumar 1.8/55mm bought by Christophe with a Spotmatic F december 21st, 2010.
And the last generation, new look.
Super Takumar 2.0/55mm bought by Christophe with a broken Spotmatic F december 20th, 2010.
Is the 2.0/55mm an "economic" version of 1.8/55mm? This one is probably not the original lens of the Spotmatic F on which it arrived ...According to aohc.it it was produced until 1973, and the Spotmatic F came out... in 1973.
SMC Takumar 2.0/55mm bought by Christophe with a SP 1000 december 20th, 2010.
This last generation one arrived with the SP1000. So economic lens on economic body?According to aohc.it, there was no intermediate "Super Multi-coated Takumar" version.
SMC Takumar 1.4/50mm bought by Christophe with a Spotmatic F january 3rd, 2011.
Christophe already had a 1.4/50mm on his Spotmatic II, here comes a second one. Unfortunately for the interest of the collection it is exactly the same.
On the EOS 400D, quite bad on the edges at large openings, because of the coma*. I have the same exposure time at f: 1.4 than with the Helios 44 at f: 2.0 ...
*It seems that this phenomenon of coma is due to an incompatibility between the lens and the sensor of the 400D, the quality is perfect with the Sony α7.
the mirror of the 5D bumps on the back of the lens!!!