When deciding which system to settle on, the variety of lens mount types and formats can be overwhelming. However, while having cameras with different-sized sensors can be problematic, it can also be advantageous. Buying a full-frame lens for your APS-C or Micro 4/3 camera will mean the image circle is considerably larger than the sensor area. This effectively eliminates the frame edges – where any lens, even a pro model, performs at its weakest, and as a result vignetting is reduced, centre-edge sharpness is more consistent, and distortion is minimised. You have the additional weight to contend with and, potentially, adaptors to consider, but ‘buying bigger’ than you need also future-proofs subsequent upgrades to a larger-sensor camera. The grey areas in the image show zones of weak sharpness.…