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Mamiya 645 Lense Conversion Chart

Wil Ussery , Jan 03, 2008; 07:58 p.m.

Can someone give me the calculation on what is the equivalent lense in 645 format as compared to 35mm. I am interested in a wide angle for the Mamiya 645 Pro and see there is a 45mm and 55mm lense available. How do these two lenses compare to a 35mm lense in 35mm format?


Wil Ussery , Jan 03, 2008; 08:21 p.m.

After further searching I found this website.


Steve Parrott , Jan 03, 2008; 08:38 p.m.

A quick and easy method is to use a factor of .6 when using 645 film. So a 45mm medium format lens on a 645 camera gives an equivalent in 35mm terms of aprx. 27mm. By the way, I have the Mamiya 45 mm lens I use on my 645e. It is a great lens, very sharp and gives you a tad more wide angle than the 55 would.

Dave Redmann , Jan 04, 2008; 09:47 a.m.

Assuming you print at the common larger US sizes (8x10, 11x14, 16x20, 24x30), then the conversion factor from 645 to 35mm is 0.578 and the conversion factor from 35mm to 645 is 1.73.

Obviously, then a 45mm lens on a 645 is like a 26mm lens on a 35mm, and a 55mm lens on a 645 is like a 32mm lens on a 35mm.

By the way, I think there is an even wider lens--maybe 30 or 35mm--for the Mamiya 645 system.

Jean-Louis Llech , Jan 04, 2008; 02:19 p.m.

A comparison between actual dimension of 645 film format (41.5x56mm) and 24x36 gives a 1.61 factor.
For Mamiya 645 lenses it gives : 35=22mm, 45=28mm, 55=34mm, 65=40mm, 80=50mm, 120=74mm, 150=93mm, 210=130mm and 300=186mm

Bill Caulfeild-Browne , Jan 04, 2008; 05:15 p.m.

Simply divide the MF lens by 3 and multiply by 2 to get the 35 mm equivalent. It's close enough. bill

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