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06-30-2010, 10:22 PM   #16
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QuoteOriginally posted by Digitalis Quote
the Sigma 100-300mm APO EX DG isn't entirely parafocal*, if it was that technique would be fine. But in my usage I have had to refocus when I zoom with this lens.
*meaning that the focus remains where you left it, regardless of your zoom setting. Parafocal zoom lenses above 100mm are sadly, are an almost unheard of rarity these days.
Agreed. But I think it's a feature primarily important for Manual focus lenses. Ironically, I previously started a fairly interesting thread touching on Varifocal versus Parafocal "true zoom" lens behavior.

My point was more about how often it's difficult to *find* the subject matter through a 300mm telephoto, period. Zooming out, you can better find the subject, zoom in, tap the AF to dial in.


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