They pitted the 38 effective MP shooter of the Lumia 1020 against the 19 MP one on the 1520, the 8 MP of the thin 925, the 6 MP snapper on the 2520 tablet, which is also used on the 720, and finally the basic 5 MP unit in the budget Lumia 625.
While Lumia 1020 had no sharpening used at all, and it gave the most accurate color representation, it was also the slowest among the phones tested. The huge sensor doesn't really help when the photo has to be processed, so Lumia 1020 took its time. We noticed the same thing in our camera comparisons - Nokia's flagship is as quick to focus as the others, but shot-to-shot times are very slow in comparison.
Next slowest was the Lumia 1520 with its near-20MP sensor, and it also introduced reddish hue over the shots, scoring low on the color representation scale. Actually the two cheaper phones only measured up against the 1020 monster and the 1520 phablet in color fidelity and speed, stepping aside for the other aspects.