BREAD AND BUTTER… WITH JAM AND CREAM

With Canon’s fullframe mirrorless camera system still relatively new, there’s a likelihood that only a few of you are actually in the market for the new RF mount 70-200mm f/2.8 L series zoom, but this lens is significant for other reasons. It’s a great example of what’s achievable when lens designers no longer have to worry about the mirror box in a reflex camera. With this assembly out of the way, the rear of the lens can be much closer to the focal plane thanks to a shorter flange distance. For Canon, it’s 20mm for the RF mount as opposed to 40mm for the EF mount on its full-frame DSLRs.

The key benefit is a shorter back focus distance that makes it easier to achieve more uniform centre-to-corner sharpness. There’s also more scope for what lens designers can do with an optical construction, especially for wide angles, particularly with the smaller format sensors. Moreover, there’s the potential to make a lens more compact, which is quite dramatically illustrated by comparing the RF mount 70-200mm f/2.8 with the current