Canon's radical brainstorming in the field of optics shows no sign of slowing down, as the manufacturer has just designed a zoomable teleconverter for its RF mount lens system.
The manufacturer already has a pair of standalone, fixed magnification teleconverters for the EOS R family – the Extender RF 1.4x and Extender RF 2x. However, this new design boasts three magnification settings: 1x, 1.5x and 2x. This would offer a level of flexibility not seen since the days of film SLR cameras.
Unlike traditional teleconverters, it does not appear that this new 1-2x converter possesses an element that protrudes into the lens – something that prevents the existing Extenders from working with either the Canon RF 70-200mm f/2.8L IS USM or the Canon RF 70-200mm f/4L IS USM.
Rather, according to the report by Canon News, the new converter will work with the Canon RF 100-500mm f/4.5-7.1L IS USM lens. As such, if it does indeed sit completely outside the lens to which it's mounted, it isn't out the realm of possibility that it would also be compatible with one or both of the RF 70-200mms – removing one of the only weaknesses of those optics.
"Will we ever see it? I'm not sure, but it certainly sounds like a great idea to me," says the report. "It's not a complete patent as it does not go into a great amount of detail on the optical formulae, but someone in Canon is certainly thinking about this. This patent deals with the cam movement of the lever and the elements to change the focal ratio of the teleconverter."
Of course, this isn't the first time that we've seen a zoomable teleconverter. In the film days we saw teleconverters like the MT Variable Auto Teleplus 2x-3x for Minolta cameras, so the idea isn't without precedent. And if Canon can resurrect it for the mirrorless era, it would be another fine feather in its cap for this generation.