--- Wieland Willker <[EMAIL PROTECTED]>
wrote:
> I WANT TO BELIEVE!
... it's science! ;)
> I was thinking about obtaining the 100mm macro, but
> now I am hesitating. I actually don't
> buy a 100mm macro but a 60-70mm macro. Is this worth
> the money? Hmm..., hmmm....
> Enablers, speak up please!
>
> Best wishes
> Wieland
>
Only at magnifications of 1:1 the focal length is
~60-70 mm or so. When the lens is set at 1:2 or
smaller magnifications, you have a focal length
significantly longer than that (most probably you
won't always work with the largest possible
magnification). Actually, there is not that much
difference in subject to film distance at e.g. 1:2 or
1:3 between the FA and M100mm macro. (Thus, with the
FA 100mm set at 1:2, you are also much farer away from
the subject than with a 50mm+extension rings or with
the M50mm macro at 1:2.)
BTW at 1:1, with the FA100 macro, the distance between
the subject and the film plane is still 10 cm larger
compared to FA50mm macro (31 vs. 20 cm), which makes
subject illumination easier.
Besides, decreasing the focal length at large
magnitudes decreases the needed exposure factor (as
the absolute opening remains constant; similar to the
zooms with variable aperture). So this has advantages
too.
Alexander
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