02-26-2015, 03:31 PM
Let's do the math then: 4/3 = 1.33. What is 6/4.5? 
You're right, there were many different aspect ratios for medium format film. However, 645 was pretty dominant in the film days and is also the dominant format in medium format nowadays. The most common "crop"-sensors in medium format are 44x33mm, which is obviously also 4:3. In fact, I think the only medium format camera that doesn't use a sensor with a 4:3 aspect ratio is the Leica S.
I guess 4:3 is more than common in medium format
You're right, there were many different aspect ratios for medium format film. However, 645 was pretty dominant in the film days and is also the dominant format in medium format nowadays. The most common "crop"-sensors in medium format are 44x33mm, which is obviously also 4:3. In fact, I think the only medium format camera that doesn't use a sensor with a 4:3 aspect ratio is the Leica S.
I guess 4:3 is more than common in medium format