Very useful lens 1

There is little to say about the quality of what is not said before.
Ca's are available, but in JPG using automatic camera correction (if any) no problem, anyway, since an automatic lens correction is supported by the great majority of RAW converters in RAW format.
The same goes for the, for a very low distortion wide angle, also applies here in an emergency, the automatic correction.

You have to make an effort to generate Lensflares by point sources of light.

For this reason, a word about the riesiegen Geli for this objective:
This can save you need because
1. they theoretically can act only in 10mm,
2. the not already doing at 10mm, you can reach through additional shading by hand still a significant improvement and notes that there is much more air until you see the hand in the image.
The panel would simply be greater and better adapted to the lens, maybe it's originally developed differently for a UWW Canon that a much larger field of view has.
3. The size of the lens is clean in any camera bag more reasonable.
4. Due to the large diameter and short length, the front lens is still relatively unprotected.

So do not be sad if that is not supplied. As Geli they good for simply nothing, the only reason is the slightly better bull bar.

I've sold these reasons my back.