Vignetting or crappy filter?

Can anyone give me a bit of help, im not really bothered about the photo in question, just asking about the vignetting or if the polarising filter i used caused this? Come to think of it im struggling to remember if i had the filter on now, but i know the hood was on it.

5Dmk2 and 24-105

How can i prevent this in the future? It is 3 stacked shots.

I have this happen occasionally when I stack two filters (polarizer + 6-stop ND) at the widest angles, so that could be it. I just have to zoom in a little bit tighter and it goes away. The only other time I had this happen was when I bought a cheapo petal shaped lens hood and the hood was too big. I replaced it with a smaller hood and that solved the problem. I would zoom out to 24mm on your lens and check for interference from both the filter and the hood.

Yeah its the first time it has happened, i can eliminate the hood as i know its the one for the lens and its always on correctly. I guess ill just have to go out again and replicate it but like you say just zoom in a tad, at least ill know what to look for now.

Thanks Jen.

Very likely that the polarizer was affecting the edges of the shot and not the center.

Each of the items you mention are easily tested and will determine which is the culprit better than us guessing.

I own the same lens and use it on my 1DsII which is also a full frame camera and don't recall ever having vignette issues with that lens. Most of my landscapes I use an original version 16 - 35 and always have vignetting when shooting at 16mm. I keep a UV filter on at all times (on both) and I'm sure that is not helping.

Polarizers have different effects depending on the angle relative to the sun.
More effect shooting at right angles to the sun.
WA lenses have such a range of angles that they do produce different levels of sky darkening in different areas of the sky, in my experience.
Just a thought.

The 24-105 tends to vignette a lot at 24 mm.

Sgt. wrote in post #13305041
The 24-105 tends to vignette a lot at 24 mm.

Agree. Even at f8. DPP does a good job of removing it, and with that lens/camera combo, the setting should already be set.

tmcman wrote in post #13301876
Polarizers have different effects depending on the angle relative to the sun.
More effect shooting at right angles to the sun.
WA lenses have such a range of angles that they do produce different levels of sky darkening in different areas of the sky, in my experience.
Just a thought.

I agree. This looks very much like a polarizer effect. Notice that there is no darkening at the bottom corners.