I'm a new owner (1 week) of a Canon 7D and a 28-135 USM lens. While experimenting and just shooting randomly, I was surprised to see my aperture setting (through the viewfinder) showing me a 2.8.

Is there anything I could have set via knobs or dials or custom functions which could account for that? I thought if a lens was 3.5-5.6, that you simply couldn't get a 2.8 reading on it.

I was in bed, in a room lit by 1 light, shooting at pictures on walls, furniture, and the TV when it happened.

This whole incident is throwing me and making me feel like I have no idea what I am doing.

Any thoughts?

  • 3
    \$\begingroup\$ Just for the lulz, but what does the exif data say ? \$\endgroup\$
    – Berzemus
    Commented Jan 28, 2013 at 16:08
  • 2
    \$\begingroup\$ Are you sure it wasn't displaying 2"5 for the shutter speed? Also, the EXIF would be interesting in this case. \$\endgroup\$
    – dpollitt
    Commented Jan 28, 2013 at 18:11
  • \$\begingroup\$ Could it have been saying f/28? \$\endgroup\$ Commented Jan 28, 2013 at 19:29

1 Answer 1


That is impossible unless either your lens or camera is damaged. The aperture on your lens opens up to a maximum of F/3.5 and it cannot open more. The aperture value is transmitted by electrical contacts on the lens mount.

Clean the contacts. If the problem remains, there is something wrong with the communication and you would have to get your camera/lens fixed. If it shows the wrong aperture, it will not be exposing properly.


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