Sigma 24mm f/1.8

Focusing distance: 18cm / 7.1in
Magnification: 0.37x
Filter size: 77mm
Lens size: ø83.6mm x 87.9mm / ø32.9in x 34.6in
Weight: 520g / 18.3oz
Construction: 10 elements in 9 groups
Accessories: Hood, Case

Eddie's take on it

This is one of those Sigma primes from an era when Sigma was not the manufacturer it is today. Along with the 50mm f/1.4, this is a full frame lens with a bad reputation. Sample variation, back/front focus, soft wide open, weighs half a kilo. Not many people bought one, and there is not much info about it. It is generally thought to perform pretty badly until stopped down to f/2.8, at which point you might as well be using one of the excellent Olympus zooms.