Canon 24mm Ts E Views
Physically its a solid chunk of iron with a narrow passage for light and glass down the middle. I'd stand on it on a dare, no problem. The front element is rather big and exposed, though not as bad as the Canon 14mm's that look like glass softballs. The lens volume doesn't change during focus, so it won't suck in dirt and moisture. The lens front doesn't rotate. The manual focus feel is smooth and heavy, nearly hydraulic. If I'm mugged my plan is to throw this lens at my assailant's head as hard as I can, and I won't be suprised if the lens survives longer than I do.
At f/3.5 it's not bright enough to really light up a split-circle focus aid. You have to be precisely centered on the exit pupil to get both halves illuminated. Also, the difference between in- and out- of focus on a wide-angle lens at f/3.5 is hard to aprise merely through a normal laser matte screen. Especially if you are used to having AF on and CF4 off on your EOS bodies, you will waste alot of film out of habit. (Canon L lenses all autofocus silently, so its easy to depress the shutter half-way, affirm that the viewfinder doesn't look obviously out-of-focus, finish depressing the shutter on a fuzzy scene.)
On the subject of focusing screens, Canon makes a grid screen for aligning architectural subjects -- with no manual focus aid. When their architectural lenses are manual focus only. You got to wonder what the hell which they expect you to load into your EOS-1N. I use a split circle screen, and line up horizonals on the autofocus squares. And curse Canon while doing it. Beattie/Intenscreen make almost the screen you'd want - both a grid and split - but not for EOS. (Ideally you'd want two splits so you could focus near/far compositions with tilt, like Fuji makes for the GX-680's. Ideally you'd just want a GX-680.)
The lens hood is vestigal at best, in order to avoid blocking the maximal field of view. They could have made an asymetric hood that protected two or three sides taking advantage that only 1/2 the picture at most can be accentuated. But in practice you're outside, shifting up, so the top of the hood (where the flare's coming from) would have to be the least-hooded side anyway. Depressing. Also at 24mm/3.5, any dust on the front element will be alot nearer to in-focus, so instead of lowering contrast undetectably, dirt will walk out of your photo and introduce itself when illuminated by stray light.