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Forums DSLR Video Searching for parfocal constant aperture lenses

  • Searching for parfocal constant aperture lenses

     ryan elder updated 1 year, 11 months ago 4 Members · 7 Posts
  • Ben Edwards

    December 5, 2012 at 6:02 pm

    OK, so my Sony Z1 seems to of gone wrong and as I am shooting a lot of DSLR stuff so thought rather than replace it I would upgrade my DSLR kit and get some suitable lenses. And by suitable I means lenses that are

    1) Parfocul
    2) constant aperture
    3) Image Stabilised

    The last may not be necessary for wide angle but the rest are.

    I Have found some info about the Canon branded lenses but not much and nothing about 3rd party lenses. I did read somewhere that some of the new cheap Canon kit lenses are parfocul and also there must be some 3rd party top end lenses made for DSLR shooters (surly Zess make some).

    I have writern up what I have found here https://www.funkytwig.com/blog/canon-dslr-lense-parfocal-constant-aperture and will update it as I get more info.

    So if anyone knows of any parfocal lenses please let me know.

    Ben
    https://www.funkytwig.com/contact-us


    Ben Edwards – Freelance Picture Editor

    Ben Edwards

    i5 550, Windows 7 / Mac Lion, Nvida 550 Ti, 8GB Mem

  • Mark Shepherd

    December 12, 2012 at 7:14 pm

    My Sony Z1 died and I made the move the Canon 5DMark11I about 6 months ago. As far as parafocal lenses with constant aperture, the only ones that I know of are the Canon 16-35 2.8 L (non IS), and the 70-200 VR11. The kit lens 24-105 is a great lens for video, but NOT a Parafocal. When you focus at 24 and zoom in, the focus shifts. Focus is a bitch in video, you have to stop recording to focus. The Live view with the 10X foom in works great for focusing (before shooting)

  • Bob Cole

    June 23, 2013 at 6:35 pm

    [Mark Shepherd] “When you focus at 24 and zoom in, the focus shifts.”

    The usual technique is to zoom into max telephoto, focus, then zoom out.

    I’d be interested in whether anyone has made an actual lab test of parfocal Canon zooms.

    Bob C

  • ryan elder

    February 6, 2019 at 8:59 am

    I’ve tried zooming all the way in then focusing, and then zooming out but this doesn’t work, because even though the lens still looses focus during the actual zooming before going into focus at the end of the zoom.

  • ryan elder

    February 6, 2019 at 8:59 am

    I’ve tried zooming all the way in then focusing, and then zooming out but this doesn’t work, because even though the lens still looses focus during the actual zooming, before going into focus at the end of the zoom.

  • Bob Cole

    February 6, 2019 at 1:35 pm

    Not sure of the source now, but I heard from some expert at a trade show that some newer zooms, those with the option for automatic focus, will also act as if they are parfocal, even though they are not truly parfocal “optically.”

    The theory goes: Even in manual focus mode, the electronics in the camera/lens combo will compensate for the lens’s tendency to go out of focus when you change focal lengths.

    Perhaps the lens you are testing has this feature, but there is a time lag?

    Bob C

  • ryan elder

    February 6, 2019 at 5:46 pm

    You mean my lens? There might be a time leg, yes. Cause it goes back into focus when it’s done.

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