Ljós
Well-known
I recall that the body of OM bodies (M-1, OM-1 (md, n), OM-2 (md, n) ) is the same as the Leitz Leica M3, the OM-2S and up is a few mm higher.
At least my ex M6 was a some what bigger than my OM-1.
It really depends on how you measure it. Overall, the OM-1 certainly looks more nimble and smaller. It is deeper though, because of the mirror housing and shutter speed ring in front. And even though the top deck sits deeper than the top of a Leica M, the prism top edges out over the Leica. So it is a teeny bit bigger in these two dimensions.
Now if you put 'em in a bucket of water 🙂 and measured how much water they dispersed, I think the OM would clock a few milliliters less. I just did not try that with mine ;-)
Greetings, Ljós