Like all medium format cameras, the mirror on the mamiya 645 is pretty large and heavy. the mirror lockup lever takes it out of the equation once you've composed and focused your image, so that the vibration its action causes doesn't blur the final shot. it's pretty much essential if you're taking exposures longer than 1/60.
A Mamiya 645 film camera can be purchased through eBay for about $150-300. Specialized camera/photo stores may also carry this specific camera. Amazon, also appears to be carrying the Mamiya 645.
0.645 = 645/1000= 129/200
The factors of 645 are: 1, 3, 5, 15, 43, 129, 215, 645.
645 kilolitres = 645 000 litres1 kL = 1000 L
The divisors of 645 are: 1, 3, 5, 15, 43, 129, 215, 645.
645 + 50 = 695
A 645-gon
645 - 19 = 626
1006
645 = DCXLV
137 + 645 = 782.
30% of 645 is 193.5