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Old Apr 27, 2005, 1:14 AM   #1
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When I use manual focusing, I zoom up to the details of the object and manually focus to it. I then zoom back to compose the picture.

Is this operation correct? Somewhere inthe user manualgave me the impression that when you change zoom, the focus may change.

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Old Apr 27, 2005, 11:29 AM   #2
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Suggest that you try it4 ways -Auto Focus & Manual Focus at the composed shot & repeat at Full zoom then recomposing using the zoom on both Auto Focus & Manual Focus. Compare the results to see how they perform.

I would imagine that the focus should remain OK but there may be a slight change as the glass changes relative position within the lens during zooming.
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Old Apr 27, 2005, 3:15 PM   #3
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I only find that necessary if I am using a fast lens like my 85mm 1.4 wide open since the depth of field is so shallow.

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Old May 3, 2005, 10:00 PM   #4
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Seems to me that the focus may or may not change depending on the lens. My lenses seems to lose a little focus when I do what you suggested.

I do know that some lenses are designed as parafocal lenses and are designed to maintain their focus throughout the zoom range(the Tokina ATX Pro series touts this).

You'll need to try it out and if the results are good, then go with it.
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