Out of a possible maximum score of 36, here’s how they scored:

Canon 24mm f2.8
Olympus 24mm f2.8
Sigma 24mm f2.8
Yashica ML 24mm f2.8
20 points
30 points
21 points
18 points

With such a clear lead, there will only be one finalist going forward from this group: the cracking little Zuiko.

Generally, it’s clear to see that the venerable Yashica was out of its depth in this company. Long in the tooth coatings, poor corners and generally sub-par resolution were revealed in this full frame test. Had it not redeemed points for its excellent CA and distortion control, the gulf would have been even greater. Again, to its credit, it is the nicest lens mechanically in the group, with smooth focus and confidence-inspiring heft, but in reality, it’s not a lens you’re going to want to use on your Canon body unless you’re deliberately aiming for a nostalgic look.

I wasn’t expecting the Canon 24mm to give such strong corner performance on a full frame sensor: if wide open corner sharpness is critical to your shooting style, it might appeal – as long as you keep the subject a long way away: near field performance is much weaker. And it suffers from a deeply nasty case of jaundice.

The Sigma, too, was something of a surprise: as a late-night haunter of photodo, I was secretly hoping that it would pull something special out of the hat to justify its 4.2 rating . . . of course, I can’t guarantee this was the world’s best sample, and it was being asked to do its thing out of a relatively unproven EOS adaptor, but it’s a fine lens on balance – very sharp at working apertures (particularly centre frame), and without conspicuous flaws. It’s just that, in comparison with the Olympus 24mm, it has no conspicuous strengths, either.

On balance, the only one of the bunch to offer a persuasive reason to throw away your convenient autofocus on-brand lens and put up with stop down metering and manual focus is the Zuiko. Positively toy-like in appearance, it delivers in ways that no other lens among this group can dream of. No pain, no gain.

But how will it fare against the best of the rest? We’ll find out in the final . . . .