Changes in close focussing distance from 35mm to 6X7

I am contemplating a macro lens for my P67 for general use, but

including in the field. When I say general I maen also for non close

up use. I would prefer the newer 100mm design over the 135, also not

having to use extension tubes up to 1:1; it also plugs a gap between

my 165LS and 55. Am I right in thinking that, although the angle of

view is equivalent to a 50mm macro in 35mm, because of the general

scaling up for a bigger image circle, the subject to front element

distance for a given level of magnification will be equivalent to a

100 macro in 35mm?

A lens makes an (in-focus) image when 1/u + 1/v = 1/f, where f is the focal length, and u and v are the distances to the subject and film respectively. In particular, for 1:1, u must be equal to v, and by simple sums, equal to 2f. None of this involves anything about the film size, so yes the focussing distances are the same for any film size.

Hi Nigel,

 

Well Bob is right, a subject of 1cm will become 1cm on your negative independable of you use 35mm or 6x7, but when you want FULLFRAME you need to magnify more(2X)and this brings you back to the same focussing distance as a 50mm in 35.

 

kind regards GertJan