Distortion

Geometric Distortion / Close Range Performance Test

The distance to each brick wall was approximately one metre; the aperture f8. Rollover each image to make A-B / B-C / A-C comparisons.

Canon/Olympus 24mm Distortion Test
Nikon/Olympus Distortion Test

Canon 24mm f1.4 L
Nikon 17-35 at 24mm
Olympus 24mm f2.8
2 points
0 points
1 points

The Nikon’s pincushion distortion at 24mm (it is dead neutral between 20-22mm) is problematic to correct, particularly given that the worst effects are concentrated in the outward-sweeping corners, where the resolution is already relatively poor and doesn’t need further corrective interpolation. The Olympus suffers from the greatest degree of distortion (barrel), but it is almost linear in nature, and easily fixed by CS3 lens tools, or even a simple Spherize, without smearing fine detail. The Canon’s modest waveform distortion looks like barrel distortion in the middle of the image circle, but turns outwards slightly at the edges. For most applications, Spherize will do the trick, and in many instances will not be required at all.

At a distance of one metre, we see no significant reversal of the earlier results shot with the focal plane at a distance of approximately 12 metres. All the finalists appear to be as well corrected for close range work as they are for landscape duty – surprising, given that the f2.8 version of the Olympus 24mm doesn’t have floating elements for close range correction. The Nikon 17-35mm possibly claws back a little of the ground it lost earlier to the Olympus at near distance, but the difference is negligible.

Close Range Performance: f8 (Centre Frame)

ca_canon ca_nikon1 ca_olympus1
Canon 24mm f1.4 L at f8
Nikon 17-35 at 24mm at f8
Olympus 24mm f2.8 at f8
2 points
1 points
0 points

Close Range Performance: f8 (Extreme Upper Left Corner)

ca_canon ca_nikon1 ca_olympus1
Canon 24mm f1.4 L at f8
Nikon 17-35 at 24mm at f8
Olympus 24mm f2.8 at f8
2 points
0 points
1 points

The Canon still owns this aperture, showing none of its mysterious centre frame softness at wide apertures. Note the significantly greater geometric distortion in the corners of the Nikon 17-35mm shots. The Olympus 24mm is neutral in this regard but barrels out across the centre frame.