Do different lenses typically expose differently?

Discussion in 'Exposure Discussion' started by StorminMatt, Sep 12, 2009.

  1. StorminMatt

    StorminMatt Member

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    I had always thought that there was supposed to be little to no perceptable difference between different lenses when it came to exposure. In other words, f/8 at 1/250 second with one lens should give the same exposure as f/8 at 1/250 second on another lens. But, for whatever reason, it seems like there is quite a bit of variance between my lenses. For instance, my 50/1.4 seems to overexpose compared to my 24-70/2.8, probably by around half a stop (or maybe even more). Is this sort of thing normal?
     
  2. PhotoJim

    PhotoJim Member

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    To some degree, yes. The more elements are in a lens, the less light will be passed. Cinematographers use T-stops (which consider lens transmission, not just the focal length-aperture ratio) to ensure that they use the right aperture.

    Also, at wide apertures some lenses will be more prone to light falloff, which can darken the corners.
     
  3. Chan Tran

    Chan Tran Member

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    to some degree yes. Up to half a stop, I have seen. More than that then one of both of the lens aperture setting is considered out of whack.
     
  4. cowanw

    cowanw Member

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    The more I use the Soft Focus lenses such as Verito's, the more I think I am seeing a stop or more of exposure in 8X10, compared to say a Commercial Ektar
     
  5. wiltw

    wiltw Subscriber

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    The indicated aperture is just that... 'indicated' and not always 'actual'. Very common in lens tests from Modern Photo and Pop Photo in past decades to see deviation from the advertised f/stop!

    And even if the lens has a true aperture matching the rated speed, there is also the transmission differences that might be caused by multiple optical groups and loss of transmission efficiency in the air-to-glass interface.
     
  6. benjiboy

    benjiboy Subscriber

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    Yes, particularly if they have between the lens leaf shutters, It's a case of getting to know your own equipment .