Originally posted by tuco The 645D is a "miniaturized" frame of medium format. FF 645 film cameras were barely considered medium format due to its small size in many circles in the film days. And now we have a cropped version of a 645. And to give you an indication its size, look at the approximate normal lens for a given format:
35mm format = 50mm
cropped 645 = 55mm,
645 = 75mm
6x6 = 80mm
6x7 = 100mm
I concur. I'm actually a 6x6 & 6x9 shooter, but I don't talk about that much on the Pentax forum.
I was responding to someone's notion that APS-C was a digital format invented because a 24x36 sensor would have been too expensive to make at the time. APS-C is a film format designed to make smaller cameras with more features than could be offered for 135 film cameras. When digital came about, APS-C format already existed as the "wave of the future". For a digital camera, smaller and more features is what the people wanted. Attempts to approximate a 24x36 digital sensor were/are an attempt to cling to an anachronistic format, for what sake I shall not speculate publicly.
To condense my usual rant: APS-C is not illegitimately cropped from 135 unless 135 is illegitimately cropped from a "legitimate" or "medium" format, which used to be just "normal" format until 135 "crop" came about, earning the name "miniature format". I have all the digital I need in APS-C without digitally simulating film's middle step-child.
Perhaps I should say I will not buy the Pentax Full-Frame if Ricoh sells me a real digital 645 instead, but they won't make one.