Rare Sun Optical Co. Sola 90mm f4 short telephoto lens in SM34 Ø34mm mount, serial number 82453, with front cap.
The company appeared soon after WWII as Sun Koki K.K.. Early lenses had the brand names Xebec and Sola. In the 50's or 60's the company adopted the English name Sun Optical Co..
The company seems to have disappeared in the late 80's.
Sun made high quality interchangeable lenses in various mounts, and binoculars.
This is quite a rare version of the 90/4 in SM34, Ø34mm, for ALL cameras, any brand any era, with 34mm lens flange.
It appears that Sun used a special alloy metal, that actually can be appreciated by the very distinguished appearance of this lens.
The lens is in pristine condition showing almost no wear.