03-16-2011, 09:59 AM
Not completely. Is a car with continuous variable transmission a car with a gear box or not? I think it is, even if it is stepless.
However, parfocal means that a lens maintains focus unaided when zooming. If it is assisted by the camera AF module with continuous adjustments, it isn't therefore parfocal, because it requires help from outside the lens.
As to the Sigma: No, I won't. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />. I've burnt my fingers a few times too often with Sigma now. And I am perfectly happy with the TS-E 17L <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />. 2 1/2 times the price, but 10X the lens. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />
Kind regards, Wim
However, parfocal means that a lens maintains focus unaided when zooming. If it is assisted by the camera AF module with continuous adjustments, it isn't therefore parfocal, because it requires help from outside the lens.
As to the Sigma: No, I won't. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />. I've burnt my fingers a few times too often with Sigma now. And I am perfectly happy with the TS-E 17L <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />. 2 1/2 times the price, but 10X the lens. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />Kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....