on the *istD, there are four program curves. none of them except MTF depend
on the specific lens. that means that all f2.8 lenses have the same curve in
normal, high speed, and depth-of-field program modes.
Herb...
----- Original Message -----
From: "Godfrey DiGiorgi" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, September 02, 2005 1:34 PM
Subject: Re: Auto-selected shutter speed on istD/s--wrong?
Seems to me there are likely only a few Program curves. Seemed to me that
the shorter lenses stop the lens down a little faster, once it starts to
stop down, compared to the 135mm, although I didn't go all the way and
generate a set of graphs... I wonder if the MTF data from the FA lenses
is weighted into the curve too.
The points at which aperture starts to close down seem about right to me,
although the F50/1.7 does seem a little low compared to the relationship
between the 35 and 135.
