Sigma — compact manual-focus 35-70mm f/3.5-4.5 standard zoom for multiple SLR mounts
Sigma's 35-70mm f/3.5-4.5 belonged to the large family of compact standard zooms the Japanese independent maker sold through the manual-focus SLR era, aimed at photographers moving up from a fixed 50mm prime without paying camera-brand prices.
The lens covers wide-angle to short telephoto with a variable maximum aperture of f/3.5 at 35mm narrowing to f/4.5 at 70mm, focused and zoomed manually. Sigma built it in parallel for Canon FD, Nikon F, Pentax K, Minolta MD, Olympus OM, M42, Konica AR and Contax/Yashica mount bodies, using the multi-coated optics typical of its catalog zooms.
Against Sigma's longer 35-135mm and 28-80mm options, this lens trades reach for a smaller, lighter barrel that suits compact manual bodies. Centre sharpness holds up reasonably well stopped down, while contrast and corner detail soften toward both ends of the range.
Copies surface cheaply across most mounts, often bundled with film bodies. Worth checking the zoom and focus rings for stiffness, grease creep onto the aperture blades, haze or fungus in the rear group, and confirming the exact mount before buying an adapter.