Focusing a 50mm lens on a R2M vs. R3M

[kshapero]

What would be the difference in focusing accuracy on a CV Bessa R2M/A versus a R3M/A using a 50mm lens?

 

[monochromejrnl]

a little bit greater than difference between focusing a 50mm on an 0.72X M6 and a 0.91X M3

closer comparison would be the difference between an 0.72X M6 and a Zeiss Ikon (also 1.0x)

R2 is 0.7X vs R3 which is 1.0X

 

[kshapero]

a little bit greater than difference between focusing a 50mm on an 0.72X M6 and a 0.91X M3

closer comparison would be the difference between an 0.72X M6 and a Zeiss Ikon (also 1.0x)

R2 is 0.7X vs R3 which is 1.0X

You have included the Magnification but not the base length, so I do not think this is accurate. Although the relative values are helpful. BTW I think the Zeiss Ikon is .74 not 1.0 with a base length of 75 making an effective 55.9 mm. This is about halfway between an M6/7/MP .72 and a .85.

 

[kshapero]

here we are:
R3M/A effective rangefinder base length of 37mm
R2M/A effective rangefinder base length of 25.6mm