Sony, Too, Aims for Lens-Shortening Fresnel Tech

With Canon’s extremely successful 400mm F/4 DO II and a couple new cheap-and-cheerful superteles that also use the “diffractive optics” technology, Sony is now getting in on the game, according to SonyAlphaRumors. In fact, Sony has been researching this for some years. Canon’s “DO” technology is what everyone else calls a Fresnel lens. Nikon calls its equivalent technology “PF.”

Fresnel lenses (think those concentric lighthouse lenses that allow for super-large elements to be made smaller by chopping them up into concentric pieces) have become the major factor in shortening some longer focal length lenses in the past few years. Early models showed poor contrast and “busy” background blur, but Canon, and now Nikon have been hitting the mid-market super telephoto lens category out of the park. Lenses that would previously go the length of your arm, now with some designs can reach only to your elbow.

That Sony is patenting a method of reducing flare for Fresnel lenses is interesting because Sony does relatively little basic lens research. Many of Sony’s lenses are manufactured by third parties, and – while Sony does appear to have a lens design shop – its patents tend to be focused on specific lens designs and not the technology going into making them. It is possible that Sony needs to develop at least a minimal lens patent portfolio in order to better negotiate the use of important technologies invented by others.

Canon upset the lucrative super telephoto market recently with the launch a 600mm and an 800mm pair of “DO” lenses that cost only about 1/10th the price of their large aperture cousins. While they are excellent under certain (bright) conditions, they are relegated to a non-adjustable f/11 aperture, and have a few other compromises. That said, the most expensive part of the lens market is now in flux, and one of the main causes is a set of technologies that – so far – have been limited to the OEM manufacturers Canon, Nikon, and – now – Sony.