Cine lenses - what's the difference?

Discussion in 'Native Lenses' started by D@ne, Aug 30, 2012.

  1. D@ne

    D@ne Mu-43 Top Veteran

    593
    Feb 23, 2012
    Toronto
  2. Hikari

    Hikari Mu-43 All-Pro

    Nov 26, 2010
    Cine lenses are in T-stops which is not just an f-number, but it also incorporates the amount of light lost in the transmission through glass--an f-number is always "brighter" than a T-number (that might be an f/1.4 or f/1.8 lens). You want a T-number to ensure exposures between different lenses are the same--an f-number will not be accurate enough.

    Also, the focus scale is much finer. If you wanted to move a camera in toward an object and follow focus--this is done by someone called a focus puller--you need something much better than what is on a photographic lens. The focus ring and aperture ring are geared so they can be controlled by external motors. These are not like AF, by can program a lens to focus between two predetermined points in a scene or even a whole host of complex motion.

    These lenses are more highly corrected. This is so footage put together does not have a lens aberration showing the cut between different lenses.

    These are expensive lenses.
     
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  3. Hikari

    Hikari Mu-43 All-Pro

    Nov 26, 2010
    BTW, when you drop $30K+ on a camera, a $4K lens is cheap...
     
  4. riverr02

    riverr02 Mu-43 Veteran

    258
    May 2, 2011
    New York
    Rafael
    Great explanation Hikari- thanks for it. Learned something today ; )
     
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  5. D@ne

    D@ne Mu-43 Top Veteran

    593
    Feb 23, 2012
    Toronto
    Thanks...very insightful.
     
  6. mister_roboto

    mister_roboto Mu-43 Top Veteran

    637
    Jun 14, 2011
    Seattle, WA, USA
    Dennis
  7. arentol

    arentol Mu-43 Veteran

    269
    Jun 29, 2012
    True, and extremely important.

    Also zoom cine-lenses don't suffer from Parallax. So if you are zoomed all the way out and your point of focus is 10 feet away when you zoom all the way on that point it will remain in focus. In 98% of normal zoom lenses you lose focus as you zoom.
     
  8. Hikari

    Hikari Mu-43 All-Pro

    Nov 26, 2010
    I would mark that Wiki entry as suspect. Effective focal length has to change in order to focus. You can't focus with out changing either the lens to sensor distance or the focal length in the case of internal focus (IF) lenses--both methods result in the change of effective focal length. Unless it is a badly worded article where IF is badly designed.
     
  9. Hikari

    Hikari Mu-43 All-Pro

    Nov 26, 2010
    I think you are thinking of the lens being parfocal--keeping the image plane at a constant distance with a change of focal length. Parallax is related to two different points of view.