Photax — budget manual-focus 200mm f/4.5 telephoto prime, M42 and bayonet SLR fittings
Photax was a UK house brand of the 1970s-1980s, used by photographic retailers to sell budget Japanese-made optics alongside own-label cameras and accessories. The 200mm f/4.5 was sold as an affordable long telephoto for extra reach beyond a 50mm kit lens.
Focus and aperture are set by hand via knurled metal rings, with a click-stopped iris diaphragm typical of manual optics of the era. It was offered in universal M42 screw mount and bayonet versions fitting major SLR systems of the time. Element count, coating, weight and filter thread are unconfirmed and omitted rather than guessed.
A modest-aperture 200mm of this vintage is slower to focus and dimmer in the viewfinder than faster telephotos, with softer contrast wide open that firms up by f/8-f/11. It suits static subjects such as distant landscape detail or casual sport more than fast-moving wildlife.
Examples circulate mainly through camera fairs and online auctions rather than specialist dealers, priced low given the house-brand origin. Check the aperture blades move cleanly, mount threads or bayonet lugs are undamaged, and glass is free of fungus or haze before adapting to a mirrorless body.