> "Chuck Skinner" <[EMAIL PROTECTED]>
> Assuming that the 100-400 zoom is about 400mm long, that gives a
> maximum focusing distance of 900mm with a field of view of 30 X 45mm.
> So our methods are in agreement!
Hi Chuck,
Cool. The hard part is figuring out the working distance from the
focussing distance, since the front nodal point is not marked on
the lens :-(
I discovered some more fun when playing with the calculator:
http://members.home.net/jul.loke/
According to Canon, the 100-400 has a maximum magnification of
0.06 (for 100mm) and 0.20 (for 400mm) See:
http://www.usa.canon.com/camcambin/cameras/eflenses/ef100n400spec.html
I could not get the calculator to come up with a magnification of
0.20 for 400mm, unless closest working distance was 2.4m This is
clearly not the case since the lens can focus down to less than 2m.
The only way to calculate a magnification of 0.20 at the closest
working distance is if the focal length is between 233 and 300mm !!!
Did I make a mistake somewhere?
Cheers
Julian Loke
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