Prime lens.

You won't get there with 2000$, at least not if you want one of the last and best sensor. If you start a new system, I think it is worse getting one of the better sensor (E-M5, E-Pl5, GH3, or perhaps GH2 and G5) , but avoid the older Panasonic sensors (the 12megas, and the 16megas which are found in the G3 and GX1).

I think that the best zoom to date, the Panasonic 12-35mm F2.8 will be to expensive if you want to stay under 2000$ without sacrificing on the sensor IQ. Further it may be difficult to s find one in stock.

The Panasonic 14-45mm, although slower, offers a very good IQ and is probably the sharpest standard zoom issued in the system before the 12-35mm. It was offered in kit with the first Panasonic bodies (G1), it has been replaced by a lower one in subsequent models, but can still be had separately. The Olympus 14-42mm IIR coming with the E-Pl5 kit is not that bad either and even smaller and lighter than the Panasonic 14-45mm.

As I wrote earlier in this thread, I don't think that heavy and big lenses like the 12-35mm are an ideal match with RF type cameras. If this is really what you want, then get a bigger body like the G5 or the E-M5 (but that may stretch your budget); the GH3 is too big for my taste (almost DSLRs size if not weight) and would clearly put you out of your budget when added to the 12-35mm.

As for fast primes, you have the choice : the 20mm F1.7 Panasonic ancake would be very nice on an RF styled body. The 45mm F1.8 is sharp an offers great bokey for out of focus area : great for portraits and a very good value for the price. A cheap pancake addition if you appreciate wide angles is the Panasonic 14mm F2.5 pancake (can be had for less than 200$ or even 160$ on eBay).

The other primes, the 12mm F2 Olympus, the 25mm F1.4 Panasonic and the 75mm F1.8 Olympus are extraordinary sharp lenses, but pricey, especially when you add the cst of the indispensable hood to the Olympus (but you can find cheaper ones on eBay).

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rrr_hhh