Canon EF 28-70mm f/2.8L USM

A dim reception hall, the toasts running long, the room finally lit warm enough that you have killed the flash. You need the wide group shot, then two seconds later a tight frame on one face. A consumer zoom has already dropped to f/5.6 by the time you reach 70mm, so now you are dragging the shutter or cranking film speed. The 28-70 f/2.8L holds f/2.8 across the whole range. That is the entire pitch, and in the 1990s it was the lens that let Canon shooters stop hauling three primes to a wedding.

It is built like a hydrant. Metal barrel and the better part of two pounds, with a 77mm front that tells you Canon was not trying to make this small. The famous quirk is that it zooms backwards: longest at 28mm, pulling in shortest at 70mm, the opposite of nearly every other zoom, which throws people the first time they pick one up. Ring USM drives focus fast and silent with full-time manual override, and the front does not rotate, so a polarizer stays where you set it.

Wide open it is already sharp in the center, and from 50 to 70mm it is genuinely excellent, which is why it built a reputation as a portrait zoom that happened to go wide. Contrast is high straight off the aperture, holding tonal separation in faces without crushing the shadow detail you need at a dim event. Bokeh at 70mm f/2.8 is smooth enough for head-and-shoulders work. Stop down to f/5.6 and the corners catch up for landscape or big group frames.

The honest weakness is flare. The coatings are of their era, so a bright source near the edge of the frame throws veiling haze and the occasional ghost, and pointed into the sun without the hood the contrast just collapses. It also softens a little at the 28mm corners wide open. Neither one matters much for the work it was built for, but you see both next to a modern zoom.

Canon replaced it in 2002 with the 24-70mm f/2.8L, which added the wider end everyone wanted and tamed the flare, so this one became the cheap door into a constant-aperture Canon standard zoom. People still cross-shop the two used and pick this to save money, trading 24mm away for 28mm. Working it wide open in a dark room, meter straight for f/2.8 in Zone Light Meter and place your shadow deliberately; at that aperture there is no headroom to rescue a guess.