It is still an existing lens (EF17-40mmL)! Before using FF camera, I never shot such wide angle view. ~9 v( j- d5 f3 a/ D4 c/ }" dTo me, it is enough to shoot the most wide angle view of scenes.# O( N5 u3 t3 I( | \ o
7 v/ ^9 |' X( k2 WSharing own experiences with this lens, I found little difficulty to set a perfect horizontal line. (Constructive problem) , P" w7 U- ^4 j0 j7 o8 `Thus, I guess more difficult to shoot more extra-wide angle (> 93 degree) of scenes when using more super-wide angle or fisheye lens. 2 K5 u+ @7 ]3 W# R# I+ a* A1 ] ) T" A( A, [! {6 e j2 JOf course, you still could say 93 degree = x super wide... ( v7 y- ^! j3 f/ J3 _$ Z3 ^It would be considered as pure user's view.