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Today's test shows f/2.8 lens is faster than f/1.8 lens

Discussion in 'Open Discussion' started by chalkdust, Oct 15, 2015.

  1. chalkdust

    chalkdust TalkEmount Veteran

    278
    Sep 25, 2015
    Bert Cheney
    I ordered both lenses on the same day and the 40mm Heliar f/2.8 arrived 3.5 hours before the 55mm Sonnar f/1.8. So the Heliar was the faster lens today. :)

    Obviously I have a lot of fun ahead of me getting to know these two lenses and how best to use them.
     
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  2. WoodWorks

    WoodWorks Super Moderator

    Dec 12, 2012
    Ashland, OR, USA
    David
    Ah, but if lens A starts from a farther distance than lens B... :p
     
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  3. soeren

    soeren TalkEmount Top Veteran

    648
    Dec 12, 2014
    Næstved, Denmark
    Soeren
    How does that affect the dof? :)
     
  4. quezra

    quezra TalkEmount Top Veteran

    916
    Aug 22, 2012
    Well DoF is an unrelated property to lens speed. I mean I was quite disappointed with the speed of my 90/2.8 as it didn't go nearly as far as my 35/1.4 when I threw it. But the depth of field was nice and thin since I could still see it poking out from the grass where it landed unlike the 35/1.4 that just vanished. :(
     
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  5. soeren

    soeren TalkEmount Top Veteran

    648
    Dec 12, 2014
    Næstved, Denmark
    Soeren
    So reach and dof is more related to weight of lens than speed?
    How about field of debris?
     
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  6. ztryfe

    ztryfe TalkEmount Veteran

    224
    Aug 19, 2014
    Mexico
    Vic

    This is a completely unreliable result, we need to know the courier for each of these, their T values and measurement tool / chart used to arrive at that conclusion, how do we know your clock's focus was a little off on the Sonnar result? for all we know, you could had misaligned the clock hands in that test.

    great post! :p
     
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  7. soeren

    soeren TalkEmount Top Veteran

    648
    Dec 12, 2014
    Næstved, Denmark
    Soeren
    And if anyone of them use VW diesel vehicles :)
    Oh maybe there is software in the f/1.8 lens making it seem faster than it really is in test situations.
     
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