A constant f/2.8 telephoto zoom that weighs 390 grams. The interesting number here isn’t the aperture, it’s the weight.
Sigma announced the 50-120mm F2.8 DC OS Contemporary on 8 October. It ships on 22 October at $799 in the United States, with €799 and £699 quoted elsewhere, and it comes in Sony E, Fujifilm X and Canon RF mounts at launch.
It’s an APS-C lens, so the field of view works out at roughly 75 to 180mm in full frame terms, or 80 to 192mm on Canon RF with its 1.6x crop. The optical formula is 18 elements in 13 groups, including one FLD, three SLD and four aspherical elements. Autofocus is Sigma’s HLA linear motor. Stabilization is rated at 6.5 stops at the wide end and 4.5 stops at 120mm on the CIPA standard. There’s an aperture ring, and a dust and splash resistant structure with a water and oil repellent coating on the front element. Eleven rounded diaphragm blades, and a 55mm filter thread.
Close focus is 23cm at 50mm and 55cm at 120mm, giving a maximum magnification of 1:3 at the short end. That’s close enough to be genuinely useful for detail work rather than just a number on a spec sheet.
The weight is the story
390 grams in the Sony and Fujifilm versions, 410 in the Canon, and 99mm long. For comparison, a full frame 70-200mm f/2.8 generally lands somewhere north of a kilogram. You’re giving up a stop of depth of field control and some low light headroom against full frame, and you’re getting back two thirds of the weight.
Pair it with Sigma’s 18-50mm f/2.8 and the whole two lens kit covers 27 to 180mm equivalent at a constant f/2.8 for under 800 grams. There hasn’t really been a clean way to do that on a crop body before now, and it’s the kind of thing that decides whether a camera comes with you on a long day or stays at home.
For monochrome work
A short telephoto is the compression lens. It’s what flattens a street into stacked planes, separates a head from a background, and lets you work at a distance without the perspective going strange. In black and white, where you’re building a picture out of tonal shapes rather than color relationships, that compression is doing a lot of the structural work.
The usual objection is the sensor. We’ve been through that argument, and the short version is that the gap between formats in monochrome is real but smaller than nearly every other decision you make before the shutter opens. A lens you’ll actually carry at f/2.8 beats a better one left in a cupboard.
Product photograph courtesy of Sigma.