The Olympus Zuiko AF Zoom 35-70 mm f/ 4 is a lens with a built-in automatic focusing. The Zuiko AF Zoom was designed for the Olympus OM camera and it was issued together with the OM-30 camera, which was sold under the trademark Olympus OM-F.
As different from competitors, focusing detector of the Zuiko AF Zoom was phase, the image came to it through a beam-splitting prism It is not only made focusing more accurate, but also it enabled a photographer to be sure that the Olympus Zuiko AF Zoom 35-70 mm f/ 4 focuses at the chosen subject.
Indeed, additional prism did not make image quality better, but the possibility of 'real' (including AF tracking) autofocusing on a non-autofocus camera was worth the effort.
Posted by: nukemall Date of publication: 06.03.2011