Welcome, fellow nerds.
Here's my take on most of the L lenses in the Canon EF range.
There's plenty I haven't used (like fisheyes), so I can't comment on those.
Primes
14mm
I've only seen one other person with this lens, but it used to live on my Steadicam camera. So, the basic idea is that it was the widest lens before things got too barrel-distorted, so it gave you the most depth of field in the days before autofocus on cameras was reliable. When you're using a Steadicam (or gimbal), not having to touch the camera is a big advantage. I'd set the focus around 1.5m at f/2.8, and then I'd know that everything from 1m to 2.5m mark was fine, which covered most normal use cases.
But this lens had other advantages than just depth of field. Its minimum focus (20cm) and field of view worked well for getting amongst people on crowded dance floors, and its super wideness gave eye-catching effects, especially when the camera was physically close to objects. It's not a lens for beauty shots, especially with the distortion on the edges, but it's a lens for interesting shots, and forcing the user to do interesting shots. I mean, plenty of people carry a 16-35, but it's not like they're walking around with the zoom stuck on the 16mm end of that range.
Two tips. Firstly, Ken Rockwell once said something like, "With really wide lenses, go close or go home," and I think that's pretty sage advice.
Secondly, one thing worth keeping in mind is if you set the lens to focus at 3.48m at f/2.8, everything from 1.74m to infinity is in focus.
24mm
This is currently the lens that lives on my gimbal camera. It's surprisingly versatile; more versatile than the 14mm. At the same time, the field of view exceeds the normal view of the human eye, so the shots have a sort of inherent interest.
So, I think it's severely underrated, but I'm not sure I've seen another wedding photographer or videographer use it. Plenty of people carry a 24-70 of course; in fact, that's probably the wedding world's most used lens. But what a 24mm prime gives you is f/1.4 as opposed to the 24-70's f/2.8 -- which means twice as much light in dark receptions, and a shallow depth of field look when you're close to objects.
And if you're willing to go close, what you get is a combination of close-up and context. Ie, you're not just getting the object, but also its environment. I think Roger Deakins uses wide-angle lenses for the same reason. Think No Country for Old Men. A 50mm framed for a single object feels portrait, but a 24mm framed for a single object gives story.
It's worth mentioning that photographer Bruce Gilden (the street photographer who jumps out at people with a flash) uses a 28mm, and it's actually perfectly adapted to quick-fire photos. This is a hard thing to explain, but that 24mm, 28mm range lets you previsualise a shot in your mind, run in close through a crowd, and get the shot without looking through the viewfinder with reasonable chance of success.
That ability to not have to look through the viewfinder also means you can get photos from high or low angles.
35mm
35mm is basically when things get pretty (at 24mm, things are maybe more interesting/storyful than pretty). But it's a perfectly respectable all-round documentary-type lens.
Some photographers use primes, and some use zooms. 35/85 is probably the most common prime-only combination, and obviously 24-70/70-200 is the most common zoom combo.
If you're not lazy with the 35mm, and you "zoom with your feet" and get in close, it gives the viewer a feeling of physically being there. They can sense that you're close to the action.
I think Ron Galella (the infamous paparazzo from Smash his Camera) often uses 35mm to catch his subjects; and maybe the comparison with Gilden is instructive. Gilden jumps out right in front of his subject, but Galella can't get quite that close, so he needs a more tele lens.
For me personally, the 35mm lives on my camera for photos, but I seldom take it for video. For photo, you have to tell your stories with a single frame, while still being pretty if possible. For video, I'd rather have either decidedly wide or decidedly close, and skip the middle range of focal lengths (35mm, 50mm) unless I have to use them. The middle focal lengths are too "normal" for me, too close to what a human eye sees, and therefore lead to less-interesting shots.
50mm
Many videographers shoot like 90% of their weddings on this lens.
Photographers would probably find that more challenging, especially for group photos.
I do tend to take this lens as a backup in my bag -- because the f/1.2 helps in the dark, because its field of view is an all-rounder if I need it, and because it prettifies.
A gimbal with a 50mm on it is a beautiful thing.
85mm
So, obviously a great portrait lens, along with the 100mm. I take it out as my go-to close-up for receptions because of the f/1.2. But, for me personally, it sees little use otherwise, despite how pretty it is.
I find the minimum focal distance (around 1m) annoying. The autofocus is too slow. The lens is too heavy.
But I should repeat that, for many people, 35 + 85 is fine for getting through the whole day with, and gives a good chance that all your shots have a shallow depth of field look.
One videographer I know uses 50mm + 85mm. "What about wide angles?" you might ask. Well, he simply doesn't shoot wide.
100mm
For many years, I felt it was essential to carry a 100mm macro in your bag for ring shots. (Canon also has a 50mm macro, by the way, for a close-up with more environment in it.) But it's also a brilliant portrait / general close-up lens. I prefer to use 35mm/100mm rather than 35mm/85mm when I'm doing photos, unless I'm desperate for light.
I think Jerry Ghionis might like a 100mm.
My second shooter, Stefan, has been known to put this on a gimbal without autofocus on the camera, with eye-catching results, but requiring a delicate dance to hand-off between subjects.
135mm
I very seldom go here, unless I can't take a 70-200 (maybe for weight reasons). The f/2.0 is definitely nicer than f/2.8 though.
It's often not practical for candid shots at weddings; if you stand far away, you can get blocked. Plus, the minimum focal distance (around 1m, like with the 85mm) can be annoying.
One thing I should say is that just as the 24mm can force you to get close __and therefore__ force you to get interesting shots, the 135mm can force you to stand far away, and forces interesting shots that way.
Along similar lines, I've increasingly noticed that photographers go for 70-200 as an all-purpose photoshoot lens. Ie, they're taking "full" shots (head-to-toe shots) with a 70-200 lens from a distance, giving the subject beautiful background blur.
Car photographers often do something similar, by the way. Even though they're photographing the whole car, they might use an 85mm or 135mm, and just stand at a distance, and the background blur gives more a hero shot look.
Zooms
16-35
There's times when you simply want the biggest field of view you can to fit it all in (for instance, recording performances at south-east Asian weddings, or recording B&G walking through farewell arch from inside the arch).
16-35 and 24-70 are respectable gimbal choices, of course. Cameras have better autofocus now, but that also creates the danger that the camera hunts for focus and ruins the shot, so there are plenty of times when 50mm and above is probably not practical. Also, gimbal operators are frequently in situations where, as said, they want to fit it all in.
35mm is also doable for gimbals, and plenty of people do it; but that field of view is borderline too-close for me, and it's narrowed even further if you enable IS on your camera.
24-70
Default do-everything lens for most people.
24-105
This is the kit lens that comes with many cameras, and it's the classic Canon all-purpose lens. It has macro capabilities that the 24-70 doesn't; the tele end can create prettier shots than the 24-70; and the IS helps not only for handheld, but even when you're using it on a monopod.
Many professionals avoid it because it's not as sharp as other choices, and it's f/4. So, it does look more documentary than cinematic at the wider end; and, without additional light, it's not usable during the reception.
Personally, I use it a lot. It depends whether the content (eg, catching candid moments) is more important to you, or the image quality (shallow depth of field, sharpness).
In general, I'm about the content.
28-300
I've only known one person to use this lens at weddings. Most people would reject it out of hand because of the f/4-f/5.6 range, but if you just need a camera to be a reliable recorder rather than produce cinematic shots, then it's very versatile.
Put it this way -- few lenses in the still world are going to give you x10 zoom range. But shoulder-mounted broadcast-type cameras routinely have much better zoom ranges, in order to give the operator flexibility to catch any shot at any time.
Side note -- Canon used to have the XC10 and XC15 cameras, which had fixed lenses -- with a full-frame equivalent of 24-240.
70-200
Default close lens for everyone, and sharp enough to have a prime lens look.
100-400
Another lens that nobody except me has ever used at weddings, as far as I can tell. It's more like a wildlife lens. And, again, most people reject it immediately for weddings because it's too slow in terms of f-stop, and it's not sharp and pretty like a 70-200.
But, during the ceremony, it lets you get closer, more personal shots than a 70-200 -- not only when you're pointed at the couple, but also when you're picking people out in the crowd. A 70-200 simply isn't close enough for emotional single-person reaction shots.
Also, in many churches, the 100-400 lets you stand at the back of a church but still zoom in on a speaker at a lectern.
