Recently Sean Reid (pay-for review site) tested the innovative and popular Panasonic G1 with some of his Leica lenses. While I’m not going to copy his protected images or repeat his lengthy and insightful discussion, I can tell you that it put a damper on my excitement for the G1 as an entry-level M camera. It might explain why we don’t have a Leica G1.
Sean’s most revealing test pitted the G1 against the M8 in a micro-contrast face-off, using the same lens on the same subject under controlled conditions. In theory the G1 should have an advantage here if the lens resolves finely enough for its pixel pitch, as does Sean’s 28mm Summicron ASPH. This is popular wisdom because the G1 doesn’t record pixels as far from the center as the M8 does (2.0x versus 1.3x crop), and hence stays in a comfort zone.
The outcome? It wasn’t close, the M8 humiliated the G1 in the corners. I mean the Summicron looked like a bargain-bin lens on the G1.
I think we have a good explanation for why that is, and it goes back to the M8’s launch material. Look at the diagram for offset microlenses:
The G1 obviously doesn’t have these micro-lenses because it is designed for lenses that project rays that are more parallel - at least it's clear it's what it works well with. The Leica telephotos are likely to work well and the wide-angles not so well. This is a shame because the 2x crop factor invites the use of wide-angle lenses.
It's possible that when we see a Leica camera come out in the Micro4/3 format, it will have offset microlenses.