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Aperture markings on m43 to EOS adapters

Discussion in 'Adapted Lenses' started by absolutic, Apr 16, 2013.

  1. absolutic

    absolutic Mu-43 Veteran

    416
    Jan 21, 2011
    I have a question about these adapters. I've owned this one Amazon.com: EzFoto Pro Canon EOS EF mount lens to MFT M4/3 Micro 4/3 camera adapter, w/Build-in Aperture version, fits Olympus E-P1 E-P2 E-P3 E-PL1 E-PL2; Panasonic G1 G2 G3 G10 GF1 GF2 GF3 GH1 GH2 GH3, w/build-in aperture version (M43): Camera & Pho for a while now and I have used it with Olympus and Panasonic m43 cameras.

    Now my question is re: Aperture scale. This particular adapter starts at F/2.8, but when I attach my Canon 50/1.8, the F/2.8 for all intents and purposes looks wide open to me. I have been looking at the aperture blades and it does not look that they impede any light at all from coming into the lens (they are plastic apertures in these types of adapter).

    Now I know some other adapters start aperture markings at F/1.7 etc., and some are more expensive.. But isn't it all arbitrary anyway? Do they try to trick you by putting down F1.7 marking on more expensive adapter, while it is just 'wide open'..... and in my adapter F/2.8 marking on this for all intents and purposes just means 'wide open' whatever your lens wide aperture is? And the markings really don't mean the true aperture values, and instead something to give you some sort of an idea that you are closing down the aperture???? Or is it truly F/2.8? Curious
     
  2. Cruzan80

    Cruzan80 Mu-43 All-Pro

    Aug 23, 2012
    Denver, Co
    Sean Rastsmith
    Given that f-stops are a ratio between the focal length of the lens, and the opening that light is passing through, I can't see how it would be accurate for more than one specific lens. A 28mm f2.8 and a 100mm f2.8 have vastly different opening sizes.
     
  3. DeeJayK

    DeeJayK Mu-43 Hall of Famer

    Feb 8, 2011
    Pacific Northwest, USA
    Keith
    What he said. :thumbup:

    Any "f/" markings on those "behind the lens" aperture adapters are inherently incorrect, since the adapter can be used with lens of a variety of different focal lengths. I've seen some that just label the adapter with 1 through 8, and to me, those are really more honest.
     
  4. absolutic

    absolutic Mu-43 Veteran

    416
    Jan 21, 2011
    OP here, all I want to make sure is that the first label number is "WIDE OPEN" that is all I care about, that the adapter does not close on the lens, and It seems to be that way, correct?
     
  5. Cruzan80

    Cruzan80 Mu-43 All-Pro

    Aug 23, 2012
    Denver, Co
    Sean Rastsmith
    Should be. The real thing to check is if "wide open" on the adapter is at least as large as the rear element. If so, then you are fine. If not, then there will be at least some stopping down occuring.