When I think wide angle, I don't think 35mm or 28mm.  Heck I don't even think 20mm anymore, for me wide angle is something more.  I find that my 16-35/2.8 L spends a lot of time on the 1Dx.  My favourite wide angle for the last couple of years has been the 14/2.8 L from Canon.  It's ridiculously sharp, has near infinite depth of field and has very low distortion.  Who could want more?  Well as of right now, I do.

Canon announced the 11-24/4 L lens earlier this year.  They were very constrained at first and are now reasonably available.  Presuming of course that you have the $3,500 price tag.   Yes, that's right, a short zoom that costs the same at retail as Canon's 5D Mark III.  Yes I get it that great glass will outlast many bodies in your arsenal, and that great glass will often cost more than the camera body.  But photographers really had that "how much?  seriously?" sticker shock on announcement.  After all, Nikon's 14-24/2.8 costs over $1,000 less and has one full stop more light gathering power.  How could 3mm be worth that extra money, and why only an f/4?

Good questions.  Doing some fairly complex math, one will learn that to have made the 11-24 an f/2.8 would roughly have increased the size of the front element by 1.5x at least.  That would have made the very sophisticated lens grinds even more complex and larger, and that would mean a lot more expensive.  A 14mm lens on a full frame has an angular field of view of about 114 degrees.  Dropping the focal length by a mere 3mm increases the angular field of view to 126 degrees, a huge increase.  This is particularly spectacular when we remember that we are talking about a rectilinear lens, not a fisheye with all the lines being bent.  In the 11-24, straight stays straight.

That's not to say that the photographer needs to be cognizant of the impact of perspective exaggeration.  I stood 12 inches away from a wall rack of guitars and could see all six feet of it.  None of the guitars were distorted, but perspectives were definitely exaggerated.  It's been said by better photographers than I that the wider the lens, the harder it is to shoot well.  Wind through the zoom range from 24mm down to 11mm and you will see how this would be true.

Handling

When you first unbox the lens, the first thing you encounter is the lens pouch.  For the price of this lens, this cheap ass sack is an insult to the buyer.  Someone at Canon needs a shovel to the head.  Then you find the lens cap.  It's not on the lens, but is in it's own little bag.  The lens is in a separate bag with a piece of lint free shipping cloth held over the front element by a translucent plastic cover reminiscent of dollar store fake Tupperware.  Nothing says worth $3,500 like fake thin plastic.

Once you put the lens cap on, you see the immediate advantage of a lens pen.  I know that this lens would go to the desert with me and I can see readily that just like the cap on the 14mm and the 8-15mm fisheye, there are gaps in the clip mounts that serious dust particles will be able to bus through.  Seriously, if I owned this lens, I would be buying some really good Tupperware and fashioning a proper lens cap.  Find that shovel and whack this designer too.

EDIT : Since I started the review, I have bought the lens and am hunting for a decent cap.  Will keep you all apprised if I find something.

Now I know what kinds of questions you are asking.  Is it light?  No, it's a brick.  Big and just a lot nose heavy.  Is it compact?  No.  In fact it makes the 14/2.8 look like a munchkin when it is actually a fair sized lens.  If you were to start making Godzilla jokes, they would be appropriate.  And that front element is about the size of Godzilla's eyeball, so the question as to whether the lens is unobtrusive, the answer is not at all, unless of course finding a full sized Tyrannosaur in your bathtub would be considered unobtrusive.

So expensive, large and heavy with a crappy lens cap.  Is there anything good about this lens?  Yes.  Everything else is freaking magnificent.  The image quality is amazing, the distortion is so minimal you'll think that it's missing content from the edges that would normally be bent like a reed in a strong wind, and the contrast is just so beautiful.  Plus I was handholding this thing at ¼ second (it does not have image stabilization) and getting tack sharp images.  I may not be in love, but am deep in the throes of lust to the point that both the 14/2.8 and the 8-15/4 Fisheye are looking very nervous about their longevity in the camera bag.  And they should be.

Mounted on the 1Dx, the lens is very easy to shoot, and while it is definitely nose heavy, the weight of the body helps make it balance very nicely and the added grip area of the longer body makes handling a breeze.  I don't own a DSLR without a battery grip and the only body I can take the grip off is a 7D Mark II and there is no good reason to put this amazing lens on a crop sensor body.  Crop sensors are awesome to get more reach out of a telephoto, but there is no point trying to use one with an ultra wide.  So my point, and I have one, is that this lens NEEDS to be on a full frame.  Really there's no point to having it otherwise.  So if you don't have a full frame and you want the look that this lens delivers, best to call the nice people at Visa and get your limit increased because you are going to need a full frame body to go with it.

As you would expect, with that front element the size of a freight engine headlight and with such a huge curve to it, there is no filter going on the front of this thing.  I do hope that the nice folks at Lee figure out how to mount their SW150 filters to a frame that will attach to this as they have with the Nikon 14-24, but I still fear that there will be some vignetting.  A Big Stopper on this lens with a long waterfall exposure shot close would be very impressive.  I did communicate with Lee and the representative did tell me that if there is demand, they will build it.  I need to reach out to Formatt-HiTech for their perspective.  Canon says that the lens takes rear mount filters.  Translating that from the marketing-speak it means that there is a flat frame at the rear element that allows you to slip a gel that has been cut to size into the frame.  So we are not talking about optical glass here, we are at cut gels.  Perhaps for infrared?  Not sure I am seeing the real value proposition.

Once a very long time ago, I got to see a Nikon 6mm fisheye on an F3.  That lens was distinctive in that it could see behind itself with a 220 degree field of view if I remember correctly.  The Canon is not like that.  And while it is huge, its not 9.3 inches in diameter, nor does it weigh over five kilos.  This is a completely USABLE lens.  The focal length range is superb, and with the quality of today's sensors, f/4 is no issue for maximum aperture.

Specifications

Focal Length & Maximum Aperture : 11-24mm f/4

Lens Construction : 16 elements in 11 groups

Diagonal Angle of View : 126°05' - 84°00'

Focus Adjustment : AF with full-time manual

Closest Focusing Distance : 11 in. / 0.28m

Filter Size : Rear insert-type

Max. Diameter x Length, Weight : 4.3 in. x 5.2 in., 41.6 oz.
108.0 x 132.0mm, 1180g

Conclusions

It is expensive, but if you consider that it fills the gap of a set of primes, or a 14mm prime and the 16-35 zoom, it's not completely ridiculous.  You will probably want a body with a battery grip or extended chassis.  You might want to fabricate a more useful lens cap.  And once you shoot it, you'll wonder how you ever shot without it.  BTW I know of a couple of great deals on a Canon 14/2.8L and 8-15/4L Fisheye