Henry P is both right and wrong!

Vignetting caused optically from within the lens (i.e as a result of the
distance and angle of exit of light from the diaphragm) is lessened as the
lens is stopped down.

Vignetting caused mechanically from outside the lens (e.g as a result of
filter ring(s)/too lengthy a hood etc.) is increased as the lens is stopped
down. The focused distance also has an effect.

Hope this helps

Craig Z

----- Original Message -----
From: "Chip Louie" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, October 19, 2001 12:13 AM
Subject: RE: EOS Just used my EF35/2.0... (sigh)


>
> Hi,
>
> Was just wondering something.  I recently suggested that someone with a EF
> 28-105USM and a vignette problem try testing wide open and stopping down
> until the problem went away to see if the problem was the lens or the
> filter.  Henry P. said that lenses that vignette will be at their best
when
> wide open and get worse as they are stopped down.
>
> This is just wrong in my experience and there was a long string of trying
to
> explain the whys and wherefores by many others.  I just watched as it got
> silly and must have missed the end of it.  The recent mention of the
French
> magazine CD and their test results on vignette refreshed my memory and I
> wondered if after all of Henry's insistence that he was correct if he ever
> said he was mistaken or if everyone else just gave up?


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