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Fixed f-stop, parfocal, image stabilized zoom for m43?
  • MamumpofuMamumpofu

    Looking for a fixed f-stop, parfocal, image stabilized, zoomable Zoom option for Panasonic GH2. After a month of searching I was wondering it this could be the one to work : Sigma 17-50 2.8 OS with "live" adapter. Which mount would be best to use EOS, Nikon, Pentax ? THX

  • 20 Replies sorted by
  • Vitaliy_KiselevVitaliy_Kiselev

    What exactly is "live adapter"?

    Fast modern m43 zoom usually is not parfocal :-)

    And I do not know how you want to make Sigma function on m43.

  • MamumpofuMamumpofu

    Thank you Vitaly! Metabones adapter should be coming soon. Sigma supposedly is parfocal and used in RED

  • Vitaliy_KiselevVitaliy_Kiselev

    Metabones adapter should be coming soon.

    Soon is very vague term. Few makers announced and even showed such adapters, but none ever become finished products.

    Sigma supposedly is parfocal and used in RED

    Any reason why you so need parfocal zoom?

  • MamumpofuMamumpofu

    Do you have another suggestion ?

  • Vitaliy_KiselevVitaliy_Kiselev

    Do you have another suggestion ?

    I asked why you need only parfocal lens.

  • MamumpofuMamumpofu

    I need it for rapid zooming - if that satisfies your answer.

  • Vitaliy_KiselevVitaliy_Kiselev

    I need it for rapid zooming - if that satisfies your answer.

    Rapid zooming for what?

  • tonalttonalt

    What does the purpose matter?

    I'm also interested about parfocal lenses. I hear often that term, but rarely see any real parfocal lenses.

  • MamumpofuMamumpofu

    it is a combination of a few things I am looking for here: rapid in and out zooming, long focusing throw or super fast AFC, constant aperture, parfocal ... any suggestions or work around ideas ?

  • RatLabProductionsRatLabProductions

    @Mamumpofu

    sounds like what you need is a fixed lens video camera. Nothing like what you asked for exists in the still lens world and cinema glass is really expensive and no auto features.

  • JuMoJuMo

    With some careful backfocus adjustments on the Metabones BMPCC Speedbooster I have had success getting the Sigma 17-50mm to be parfocal - and previously had success with the older (and less sharp) Sigma 18-50 using the same method (unfortunately it means that after the backfocus adjustments I was unable to reach infinity focus on some of my Nikon primes wide open - falls just a LITTLE short).

    Though I must say the argumentativeness earlier in the thread is very peculiar: why anyone would question the purpose of a parfocal lens is beyond me... it's obvious how useful it is.

  • MamumpofuMamumpofu

    Thank you so much for sharing JuMo - that was very helpful. I am glad people like you exist - you made my day :-)

  • Vitaliy_KiselevVitaliy_Kiselev

    Though I must say the argumentativeness earlier in the thread is very peculiar: why anyone would question the purpose of a parfocal lens is beyond me... it's obvious how useful it is.

    No one here said or questioned that being parfocal is not cool and useful. Thing is, if you want to make lens parfocal you hit design restrictions (and usually many other things suffer if you want to keep price range). Hence so few parfocal lenses amoung usual camera lenses.

    For many tasks you actually can work perfectly with varifocal lenses.

  • MamumpofuMamumpofu

    I didn't want to elaborate on the usefulness of parfocal lenses nor the price point (which is $600 vs $4000) - just plainly whether or not it was possible at all ;)

    All arguments left aside the Panasonic GH platform could produce an enormous brake right now , if they managed to produce useable zooms and/or create enough interest for the development of integrated 3rd party ad-ons.

  • thornthorn

    Broadcast television greatly appreciates parfocal lenses.

  • RatLabProductionsRatLabProductions

    For some perspective those lenses run in the $20-30K range and cover a very small sensor.

    To get the same range, parfocal nature in a constant aperture & large sensor coverage would be physically impossible in a lens you could carry.

  • thornthorn

    B4 lens + adapter?

  • brianlbrianl

    I shot with an Angi 35mm film parfocal on a GH2. It was sharp and beautiful and amazing. It could make you cry. It was also not the most practical thing.

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  • MamumpofuMamumpofu

    yes, things become unyieldingly huge very quickly. Reminds me of my Novoflex lenses. ... and they had a Quick focus 60-300 for similar reasons in the 80's. I think one answer could be sensors with progressive non uniform pixel density / resolution, and lets say a 10 - 40 long throw parfocal zoom combines with lossless digital zoom extension.

  • MamumpofuMamumpofu

    http://www.metabones.com/products/details/MB_SPEF-m43-BM1
    http://www.sigmaphoto.com/product/17-50mm-f28-ex-dc-os-hsm

    Special gift to you VK ... enjoy !

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