Actually, scale focusing will work properly on the M9 as the hyperfocal distance will match the actual depth of field recorded by the sensor, unlike with the 1.3 crop of the M8.
You seem to be a bit confused here : "the scales should work the same on the M8 as with the M9, but generally speaking a smaller sensor with give greater DOF (with a smaller FOV) for any given aperture than the larger one, so scale focus with the M9 will be less forgiving, albeit only slightly so"
Although near and far focal distances are not effected by sensor size, hyperfocal distance will actually be increased on the M9 vs the M8 for a given (real) lens focal length. Some math for you based on 8x10 final output:
H = (L x L) / (f x d)
Where:
H = Hyperfocal Distance (in millimeters)
L = lens focal length (ie, 35mm, 105mm)
f = lens aperture f-stop
d = diameter of circle of least confusion (in millimeters)
for 35mm format d = 0.03
for 6x6cm format d = 0.06
for 4x5in format d = 0.15
Of course you can scale focus and shoot from the hip with the M8. I do it quite often. It will simply work properly with the M9, like with a film M. Which is a good thing.
I think you are the one a bit confused
I said that the M8 will be more forgiving than the M9 at any given focal length because of the smaller sensor size
you are correct that hyperfocal distance with the M8 will be less at any given aperture than the M9
BUT
this means that subjects in acceptable focus will start sooner and thus the M8 will be more forgiving for scale focus than the M9, which is what I contended in my initial comment to you
the greater the hyperfocal distance, the less will be in focus
I suggest you play a bit with Barnack, a wonderful free applet written by Mikkel B. Stegmann, though the M9 is not yet supported
the link is here ------>
http://www.stegmann.dk/mikkel/barnack/
hope this helps you understand what you were incorrectly correcting me about
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pbase & dpreview supporter
DPR forum member since 5/2001
http://www.pbase.com/artichoke