07-02-2014 11:03 AM - edited 07-02-2014 11:04 AM
SHow corners? Perhaps the corners of the lens hood? If that's the case you probably don't have it set properly; make sure it's firmly seated and locked in. Or, perhaps you're using a 3rd party hood?
There's some amount of vignetting (easily auto-corrected in most processing programs) when on the wide side of the 17-40, but you still get full use of the sensor.
07-02-2014 11:22 AM
I found it. It is the polarizing filter. It seems that this lense doesn't accept two filters. A glass filter and the polarizing. Thanks for your feedback it halped me looking at this.
07-02-2014 11:43 AM
Yes, stacked filters will show on most wide angle lenses. Even at more standard focal lengths on some lenses.
Might I ask, what is the glass filter? If it's just a UV filter, take it off when using a polarizer or ND.
07-02-2014 12:26 PM
07-02-2014 01:22 PM
And you are probably not using low profile filter. I can stack 2 low profiles filter on 16mm just fine.
If it's the Canon 16-35/2.8L II you're referring to, that uses 82mm filters. The 17-40 uses 77mm.
"Slim" filters tend to be more expensive. And some of them don't have threads on the front, so need a special lens cap.
B+W's "standard" mount filters are pretty slim to begin with (tho they to offer slim, as well)... I've never had any vignetting problems with them on even the widest lenses. But I also would never stack a polarizer on top of a clear "protection" filter. Previous response to remove the clear filter first, before installing the CPL, is correct.
07-02-2014 01:26 PM
07-02-2014 01:43 PM
... I often stack ND with CPL to prolong shutter speed because my 3stop ND sometimes is not enough. I may get around to get the 6 stop or 10 stop soon.
Yup, I've done this on my 17-40 and didn't have issue, but I have the B+W XS-Pro CPL, which is super slim.