A quick test I did with this lens and the wide converter, making this lens a 12mm.
My finding are in the video, but overall:
- Sharpeness is good except in the corner
- Corners are soft wide open, improves when stopping down. at f5.6 they are pretty good.
- The adapter is great, no light loss, but it makes the soft corners more apparent.
- We can use it with a matte box.
Overall, the pair work well on the FS100, and can be used wide open depending of the subject (my subject with details all over the frame render the corner softness more apparent.)