small additions. 1. there's also no such thing as zoom lens for rf. 2. i think you can avoid the 'seeing around the periphery' problem somewhat by shooting with both eyes open. 3. i always imagined smaller glass area is always a handicap. the bigger the glass the sharper it ought to be. works even better if there's bigger film to capture the bigger image. i.e. using ever larger format cameras...the larger the sharper... 3.1. larger glass is usually also brighter. i personally always wonder about people who care about sharpness..like unless they always shoot on tripod, how does it work? they get sharp motion blur?