The 24mm World Cup
Group C: Regular f2.8 Prime Lenses

Canon 24mm f2.8 v Olympus 24mm f2.8 v Sigma 24mm f2.8 v Yashica ML 24mm f2.8:
Extreme Corner Performance at f11: Far Field (100% crops from top left)

3 points	4 points
Canon 24mm at f11 (corner)	Olympus 24mm at f11 (corner)
Sigma 24mm at f11 (corner)	Yashica ML 24mm f11 (corner)
2 points	1 point

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The Olympus has overturned the Canon's early lead convincingly from f5.6 on. And the Sigma has put in a strong showing, too. However, turning to the question of near-field performance, we see a surprising problem in these 100% crops from the extreme cornermost pixels of the bottom right of the frame, which has been present at all apertures.

Extreme Corner Performance at f11: Near Field (100% crops from bottom right)

2 points	4 points
Canon 24mm at f11 (corner)	Olympus 24mm at f11 (corner)
Sigma 24mm at f11 (corner)	Yashica ML 24mm f11 (corner)
3 points	1 point

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The lack close-range correction or floating element in the Canon 24mm really lets it down at close range. By contrast, the Sigma and Olympus excel.

Centre Performance at f11 (100% Crops)

2 points	4 points
Canon 24mm at f11 (centre)	Olympus 24mm at f11 (centre)
Sigma 24mm at f11 (centre)	Yashica ML 24mm at f11 (centre)
3 points	1 point

The Olympus is really flying at f11, with its tiny front and rear elements, it suffers far less than the larger lenses from diffraction at this aperture, and the corners have sharpened up very nicely. All in all an outstanding performance from the tiny Zuiko.