Auto Rikenon 55mm f2.8

     Back in 1967 this lens was sold as the budget option for the Singlex TLS.   It's big brother, the 55mm f1.4, is well known.   They do share one thing in common......Tomioka.    Tomioka made lenses for Ricoh, Yashica, Sears and others.   They eventually went on to make lenses for Contax.

     Mechanics are very well tuned.  Focus dampening is perfectly balanced.    Aperture clicks softly but firmly.    The aperture ring is two sided.  One side is manual and the other is auto.   Aperture clicks are full stop with every other stop labeled.    

     On the 6D. the image through the prism is a bit dark, which made it difficult to focus.     Luckily my M42 adapter has an AF confirm chip that actually works.    I also found that I has to use center weighted metering to get an accurate reading.   

     Is it any good?   YES.   It is sharp at the center from 2.8 with only a slight diffusion of bright edges.   Corner sharpness is average at f2.8 but becomes quite good by f5.6.   At f5.6 it is razor sharp in the center.   

     Contrast is quite high and perhaps at the sacrifice of shadow detail.  

     Fringing is practically non-existent.

     Vignetiing can be seen at f2.8 but it's gone by f4.  

     Barrel distortion is noticeable and a bit more pronounced than most standard primes.   It is simple and correctable.  

     Black and white tonality is very good.   

     The best characteristic of this lens is its imaging.    Pics have a 3D feel which is reminiscent of EBC Fujinon's and Konica Hexanon's.