Kajuah wrote in post #7357418
If you guys are using a lens hood, that could be the reason. It could also be light fall off from using the maximum aperture of the lens.
Is this thing able to be used on full frame?
Sure can (from about 18.5mm onwards - see my post on the previous page) And it looks sharper as well due to the generally lower pixel densities of current FF cameras vs current Crop cameras. However, the downside is that CA is much more visible at the high resolutions of current FF cameras like the 5D Mark II
Here's a handheld FF shot on a 21 Megapixel 5D Mark II, using Standard Settings:
And a 100% Border
Crop of the lower left. Note the Significant CA. The shot is a bit oversharpened by the Standard Picture Style's Sharpening but note how good the resolving power of the lens is, you can see the words "limited" and if you squint can just make out the words under the number plate: