Black on opposite corners of photo after dropping camera

[gimills]

I have an EOS 6D with a 24-105mm lens. I dropped it all while crossing a road in the middle of a two-week vacation and it bounced around a bit but was hardly scratched. When the vacation finished and I looked at all 2,500 pictures on the computer, about 15 of them were just liked the one below - two dark corners opposite each other. After those 15 pictures with the dark corners there was no recurrence in any of the pictures. I do seem to remember taking the lens off and putting it back on again about a day after I dropped the camera. Anyone know what the black corners are ? Do I have anything to worry about long-term ?

[ScottyP · Accepted solution]

Looks like the lens hood rotated a little (loosened a tiny bit).  You probably tightened it properly later.

Those petal lens hoods protrude farther on top and bottom than on the sides because more of the round lens image gets thrown away on the top.  If you fail to turn it fully around until it clicks in with the long petals right on top and bottom you will see little catty-corner black shadows, which are those petals showing up in the picture.  

When I opened my 35mm Sigma at Christmas I popped the hood on and took some shots. I thought the lens was defective because it looked just like your shot above, but I had actually just not quite tightened the hood on all the way to the click.

[TCampbell]

Hard to say what that might be.  Was there a lens hood attached and was it damaged?   

If if the optics were damaged I would expect to see distortions near the corners, but I don't see any.  If this were a shutter blade problem I would expect to see a specific tell-tale pattern and I don't see that either.

I have even seen issues where the neck-strap was in the way, but usually that would not be symmetric as seen in this image.

Can you just shoot a photo of anything (even if it's a plain white wall) and see if the camera still does this?  

[ScottyP · Accepted solution]

Looks like the lens hood rotated a little (loosened a tiny bit).  You probably tightened it properly later.

Those petal lens hoods protrude farther on top and bottom than on the sides because more of the round lens image gets thrown away on the top.  If you fail to turn it fully around until it clicks in with the long petals right on top and bottom you will see little catty-corner black shadows, which are those petals showing up in the picture.  

When I opened my 35mm Sigma at Christmas I popped the hood on and took some shots. I thought the lens was defective because it looked just like your shot above, but I had actually just not quite tightened the hood on all the way to the click.

[cicopo · Accepted solution]

Agree with the idea the lens hood rotated from the normal position. Been there myself.

[gimills]

Thanks ScottyP and Cicopo. That seems like a reasonable explanation, and I didn't even think of it !! Many thanks.