Canon EF 16-35mm f/2.8L II USM

Wedding reception, first dance, and there is a wall against your back. You cannot step back another foot and the moment is happening now. This is the frame the 16-35 owns and a 24-70 loses. At 16mm on full frame you take the whole room, the couple under the string lights, the crying aunt in the corner, all of it at f/2.8 in light that would starve a slower lens. For a decade this was the wide end of the press and wedding kit, the lens on one body while the 70-200 rode the other.

Ultrawide on an SLR forces a retrofocus design. The rear group has to clear the swinging mirror, so the whole thing is an inverted telephoto built around a deep, bulbous front element. The II is Canon's second pass at that formula. They grew the front glass and pushed the filter thread to 82mm from the original's 77mm, chasing better corners and less falloff. Ring-type USM drives focus fast and silent, which counts when you are working a room and do not want the lens hunting.

Center sharpness is there wide open. Put a subject dead center at 16mm f/2.8 and it bites. The corners are the problem. At 16mm wide open they go soft and a little smeary, and they do not fully clean up until f/8 or f/11. That is the lens in one line: brilliant middle, lazy edges. For environmental work with the subject central it barely registers. For a flat landscape or a star field where the whole frame has to resolve it matters, and corner coma is why astro shooters either stopped down and lost the speed or shopped elsewhere.

The lens it lost to on paper was the Nikon 14-24mm f/2.8, the corner king of that generation, good enough across the frame that Canon shooters adapted it onto EF bodies just to get it. Canon answered later with the 16-35mm f/4L IS, which traded the stop for cleaner edges and stabilization, then the f/2.8L III in 2016 that finally fixed the corners. So the II sits in a clear place now. Cheap used, still a fine fast lens for interiors and reportage, skippable if your work lives in the edges of the frame.

You will point it at the sun, because it is an ultrawide, and the coatings hold contrast better than you would guess, though a bright source in the frame can throw a ghost or two. Barrel distortion at 16mm bends straight lines and corrects cleanly in software. The 82mm front is the practical tax: filters that size are big and expensive, and across a 16mm field a polarizer bands the sky unevenly, so save it for the long end. Stacking an ND or a grad for a long landscape exposure, set the filter factor in Zone Light Meter before you trip the shutter so the reading matches the light the film actually gets.