Rebel T4i - problem with dark/black corners in "landscape" mode

[Amigo]

Hi I wanted to ask if someone could help. I am having problem while shooting pics. in "landscape" mode. Sometimes one, two or three corners are more or less black/dark.

thank you in advance for any advices.

Josef

[TCampbell]

Specifically which lens are you using and, are you using a lens hood?

Canon makes lens hoods specifically designed to work with each of their lens models.  They're designed to ensure that the lens can't "see" the edges of the lens hood at wide angles.  If you are using a generic hood, then I suspect your lens is catching a glimpse of the hood. 

[Amigo]

Thank you for reply. No I am not using any hood. Although in the meantime I upgraded for the new firmware and it seems that it´s not doing it any more.

The thing was that sometimes it was only in one corner, sometime in two or three. I don´t know if it could´ve been the sfw?

[TCampbell]

Very wide angle lenses can also have this issue simply if a filter (e.g. a "UV" filter or polarizing filter) is attached.

Usually if _only_ the corners are affected then it's caused by something physically blocking the light and not an electronic problem or mechanical malfunction.  The curtain shutters slide top-to-bottom (not from the corners) and likewise the CCD doesn't read-out from the corners inward, etc.  

[ebiggs1]

"... I upgraded for the new firmware ..."

It wasn't the firmware. There is something in the way!