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fast lens article

Discussion in 'Open Discussion' started by squeegee, Mar 3, 2010.

  1. squeegee

    squeegee Mu-43 Veteran

    403
    Jan 26, 2010
    with all the talk about the f.95 and all I decided I needed to do some more reading and I came across an article which kind of skims one of my concerns/confusions about the number of lens elements and light transmittion of a lens...

    it briefly talks about the accuracy or relevance of the aperture numbers.

    http://www.dantestella.com/technical/fast.html

    now if only some one could tell me what the difference between a "tv" or "video" lens is compared to a regular photo? lens? (the talked about nokton is allegedly a rebranded video lens? so? ... )
     
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  2. BBW

    BBW Super Moderator Emeritus

    squeegee, I'm bringing this thread of yours up for some morning light - morning, here where I live anyway. I'm sure some of our more technically savvy will weigh in over the course of the day/evening.
     
  3. hohoho

    hohoho Mu-43 Regular

    170
    Jan 24, 2010
    Tokyo
    Intrinsically, so nothing. However, most TV cameras are for very mundane snooping purposes (so high quality would be wasted) or need only a very small image circle or both. And the lenses that are mounted so that they'll make a record of the occasional al-Qaida member, psychopath or shoplifter don't need to have their apertures changed in a hurry and so don't have aperture click stops. (But then old camera lenses and a few new ones don't either.)
     
  4. Streetshooter

    Streetshooter Administrator Emeritus

    Dec 15, 2009
    Phila, Pa USA
    Once again,
    Cosinaphile can explain it all......
     
  5. Djarum

    Djarum Super Moderator

    Dec 15, 2009
    Huntsville, AL, USA
    Jason
    One of the things not discussed by the article, which I know comes into question when doing astro-photography, is field curvature. The faster the lens, the more field curvature a lens has. This explains why sharp fast lenses are extremely expensive. Fast lenses and flat field are hard to engineer and design.

    I think for the money, the Noktor looks like a bargain.
     
  6. squeegee

    squeegee Mu-43 Veteran

    403
    Jan 26, 2010
    That was kind of my guess. I reasoned (to myself) that a video lens only needs to resolve roughly 1920x1080 where as say a 12mp lens needs to resolve roughly 4000x3000.

    If that's the case, shouldn't we be really surprised if this noktor appears to be "good quality" when used for photo purposes?

    Something seems a little fishy here. (It's just me, I trust nothing, question everything, then try to personally test the alleged truth, then I still don't believe it :rolleyes: )
     
  7. Brian S

    Brian S Mu-43 Top Veteran

    714
    Apr 11, 2009
    A number of TV lenses were regular full-frame lenses with truncated rear groups for the smaller format. The Canon 100/2 TV lens is basicallythe front section of a 100/2 RF lens with a C-Mount rear. It would be great for micro 4/3 format. Others, like the 50/0.95 TV lens simply left off the RF coupling.

    So: I would judge the lens in actual tests. It would also be possible to tweak and cherry pick the best optics for the higher resolution digital cameras. At $750, it's less than what Canon 50/0.95 TV lenses are going for. But the CV F1.1 Nokton is not running much more, and is made for full-frame. The center performance will be stellar.