> If this were *strictly* true, shouldn't we see a proportional change
> in f-stop to the range of focal lengths? 28-105 is a range of about
> 3.5x and 3.5-4.5 is what, 2/3 stop?. My 75-300 has a zoom range of
> 4x, but is a f/4-5.6 lens, one full stop, or 2x. My 28-135 a bit
> more than 4x, and is 3.5-5.6. My math is failing me now, but you get
> the picture. So to speak.
But the lens may be designed to be adequate optically at a smaller aperture-range (2/3
stop vs 1.3 stops), so Canon has made the lense vary it's aperture diameter a little
to squeze a little more light out of it... I don't really know, but it's a good
guess...
Snorre
*
****
*******
***********************************************************
* For list instructions, including unsubscribe, see:
* http://www.a1.nl/phomepag/markerink/eos_list.htm
***********************************************************
