I came across this lens on Gumtree recently. The brand name was SUN and the glass is Japanese. Don't know a lot about these lenses but they're all metal and glass, solid and totally manual. Probably made in the late 70's. At 200mm and a maximum aperture of f2.8, I thought it may be good for astrophotography. Forget about it at f2.8, the CA was atrocious but at f 8 and beyond it seems ok and as I only paid $50 for it, I wasn't expecting too much from it anyway.
I shot this test with the lens last night under a waxing gibbous moon and a bortle 6 sky, using a modded Canon 550d on a Sightron Nano Tracker. 16 x 1 min subs @ 800 iso and around f8 - f11.
