Re: Power zoom lenses

[Mark Cassino]

I just tried my PZ 28-105 on the *ist-D and it was downright snappy in 
focusing at both ends of the zoom range.  I wonder if there is some sort of 
problem with the AF coupling on the lens?

Someone else commented that the PZ 28-105 does not focus to infinity on the 
Mz-S.  My Mz-S is off for repairs, but I don't recall ever having that 
problem. I did note testing just now that when I focus the 28-105 to a 
distant subject, distance scale on the lens reads about halfway between 5m 
and infinity. But a few test shots with the *ist-D shows that this is indeed 
where it's in focus.  I was on my back roof focusing on a telephone pole a 
block away , so I'd expect that to be infinity - but maybe the scale is off.

- MCC
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Mark Cassino Photography
Kalamazoo, MI
www.markcassino.com
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----- Original Message ----- 
From: <[EMAIL PROTECTED]>
To: <pentax-discuss@pdml.net>
Sent: Tuesday, March 08, 2005 11:12 AM
Subject: Re: Power zoom lenses


  All i know is the PZ 28-105 works on my PZ-1 with no problems however,no 
Power Zoom
with the
istD and it does not AF well at either end(full 28 and full 105)Its 
sporatic and just
started.Kind of a
humming noiise from the motor when trying to find focus.
Take it off slightly from the to ends and it will focus.

Dave
      > Carlos Royo mused:
>
> Joe Wilensky escribi�:
> > But are any of them power zoom lenses? I think most of the IF lenses
> > replaced older power zoom designs.
>
> The FA* 80-200 2.8 is both power zoom and IF. And I think the awesome
> 250-600 mm. is also both.
That is correct  (although neither lens changes length when zooming).