Originally published by yours truly in the April issue of Medium Format Magazine.
The use of any nomenclature of size already implies some degree of relativity. If a cellphone sensor is ‘small’, then arguably even APSC might be considered ‘large’. Yet there is a legacy expectation that medium format necessitates a recording area of at least ‘645’ (in itself misleading, usually being a bit smaller than 60x45mm at around 54x40mm or so) or larger. At some point – usually 4×5” – this becomes ‘large’ format. The digital sensor size of 44x33mm has challenged this somewhat, being much cheaper to produce than 54×40 (as low as a quarter of the price, due to finite wafer sizes, yield rates, etc.) whilst still offering about 68% more area than 36x24mm ‘full frame’.