My C*non 24-105/4 L has variation with focus with zooming. It holds focus
best at infinity, but focused at 10-15 feet it varies a lot. Whereas the
70-20/2.8
and 16-35/2.8 does quite well holding focus while zooming at close distances.
WayneS
At 10:30 AM 6/11/2009, you wrote:
>Ken, my experience does not agree with you on this point -
>I have used about a dozen Canon EF-series zoom lenses, and every
>single last one of them, from the cheap kit lenses, to the monstrously
>expensive 28-300mm L IS USM, maintained a constant focus distance
>regardless of focal length.
>
>On 11 Jun 2009, at 4:11 PM, Ken Norton wrote:
>> Most modern lenses are zoom lenses. Most zooms now are a form of
>> "Varifocal"
>> design. As such, you cannot zoom in on a subject, manually focus (or
>> focus
>> lock) and zoom back out and expect the focus to stay put.
--
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