While looking at the photo you can’t really tell is it using an ultra wide or not, but for me 10mm is really a deal breaker. The coverage is so wide that it is just impossible to do it before, all my shoot in here wouldn’t be possible if I am using my 18-55mm. If I want to use 18mm to cover the same coverage, I would need to take 4~8 shoot and stitch them together for the same effect.
But the convenient also came with a cost, it is much more difficult to make a good composition and level the photo nicely due to distortion of the coverage, so have to be quite careful when composing. But it also make sell portrait so much easier >w<