Simon Joinson has the following conclusion on the JPG photo output quality from both cameras:
It’s clear to see that Olympus – as usual – is doing a great job with its out of camera JPEGs, and at a pixel level the E-P1 produces, sharper, crisper output than the Nikon, and the punchier default contrast, sharpening and saturation mean that the results are more immediately appealing. You’re not going to see a huge difference at normal magnifications (and turning up the Nikon’s rather conservative sharpening evens things out a little), but there’s no denying that the little Olympus is giving the D5000 a good run for its money (though again the rather harsh highlight roll-off produces slightly clipped tones at ISO 100).
Lenses used were the Olympus 50mm f/2.0 Telephoto Macro ED on the E-P1, and Nikon 50mm f/1.4G AF-S Nikkor on the D5000.
