I'm using a Sony A7 II with adapter with a Canon EF 24-70mm f/2.8L and a Canon 16-35mm f/2.8L both with the same settings, but the exposure on the 24-70mm is darker in the manual and action modes, but in automatic and portrait it shoots completely fine only with a bit of lag.

I tried detaching the connection between the lens and the body and just slightly connecting them to generate a image; I think there's something wrong with the lens. Like it has gone really dark for some reason.

I have a feeling that something in the lens needs to be fixed.

Any advice or help to fix it would greatly be appreciated.

I don't think the body/adapter is the issue, as I have also tried it on my Canon 60D, and the same issue occurs.


1 Answer 1


Your maximum f/stop is different at different focal lengths, even with the same lens. I had a 55-255mm lens that at 55mm max f/4 but at 255mm my f/stop would not go below f/5.

  • 1
    \$\begingroup\$ except the OP's lenses have a constant maximum aperture of f/2.8 each. Those lenses have f/2.8 throughout the zoom range. I'm not familiar with any 55-255mm lenses, but if you're talking about the Canon 55-250mm f/4-f/5.6, then indeed, it had a variable max aperture. \$\endgroup\$
    – scottbb
    Oct 29, 2016 at 19:15

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