Today Olympus officially announced the 75mm f/1.8 lens for m4/3 after its long leak engagement. In keeping with the apparent new m4/3 strategy of leaking, previewing, pre-promoting, announcing, and then eventually releasing, the lens announced today won't be available until summer some time. In other words, from the time we first heard details of this lens to ship will be at least eight months.
I guess the good news about this methodology that both Olympus and Panasonic now seem to be using is that we don't need lens road maps, because the early leaks are as good as a roadmap (Olympus also has leaked and previewed a 60mm f/2.8 macro lens, and Panasonic is still in the process of previewing their 35-100mm f/2.8). The bad news is that, coupled with poor distribution and dealer coverage here in the US, this is provoking high demand for things that aren't available in enough quantity at initial shipment. I know of dealers still waiting for their first E-M5 body here in the states, and I've written before about Panasonic's neglect of the US market during early shipments. So at least here in the US, the companies are getting people excited about things they probably can't get one day one.
But you want to know about the lens. I suspect you already know most of what there is to know. Full details are on my data page for the 75mm lens. The only new news was the US$900 price and the "summer 2012" release "date".
At 75mm, the new lens gives you a very fast 150mm equivalent for m4/3. Compared to the current zooms we have available that cover that range, the 75mm has about a three-stop advantage in terms of aperture, meaning that you'll be able to get shallower depth of field or use an ISO value three stops lower, all else equal. Even compared to the upcoming 35-100mm f/2.8 from Panasonic, the new 75mm will still have a bit more than a stop advantage at 75mm.
Olympus is slowly rounding out their prime lenses for the m4/3 system. We now have 12mm, 17mm, 45mm, and 75mm lenses, with a 60mm macro coming. Of those five primes, four are high performance, high quality (the 17mm is the exception and really needs a redesign). Coupled with Panasonic's 14mm, 20mm, 25mm, and 45mm macro, we now have a pretty full range of prime options from 24mm to 150mm equivalent, with only the 17mm (35mm equivalent) being a weak spot.
Memo to Nikon, Samsung, and Sony (and Canon; I know you're out there thinking about mirrorless): one reason m4/3 is doing so well is because of its lens support. By the end of this year m4/3 will likely have pretty much every major lens option that an enthusiast really would be interested in, and a lot of redundancy in options for the true consumer, too. Remember, these are "systems" not cameras. Thus, the m4/3 system is now broad and deep. Nikon, not even close. Sony, not even close. Samsung, a tiny bit better but still not close.
So, to Olympus and Panasonic: congratulations: you're delivering what photographers actually are interested in. For that we're all thankful.