I used to be seeking the perfect P&S - one that was good enough in quality to allow me to abandon the idea of carrying my dSLR for all but the most critical situations (naturally the dSLR is the first choice in the home or studio as weight and size are not factors). I've slowly come to the conclusion that there are too many disadvantages. It isn't that great shots can't be had from a small sensor camera with zoom, but the problem for me is that beyond scenics and travel photos, they just don't differentiate themselves enough. They can't get truly shallow depth of field, except in situations where ALL cameras can get shallow depth of field. They get noisy when the light goes down. Focus is relatively slow and focus point selection and so on is not fast. Manual controls are nice, but with the increased depth of field selecting an aperture isn't really making much difference.

So I've long been a fan of the micro four thirds format. But for a long time now it has been lacking a good portrait lens, with fast aperture. Enter the Olympus 45mm f/1.8 micro four thirds lens. I have had it for over a month now and use it on my GH2. This lens has completely changed how I am going to use cameras going forward. Here is the run down:

1. Size. This is a very small and lightweight lens. The smallest and lightest Canon lens I've ever used is the 50mm f/1.8 plastic lens, and the Olympus is ever lighter and smaller than that.
2. Focal Length. The 45mm focal length gives a basic field of view of a 90mm lens on a full frame camera.
3. Aperture. F/1.8 is fast enough for me. It is quite sharp at f/1.8 or f/2, much more so than any Canon prime I've owned except for macro lenses. This lens is very similar to my 60mm f/2.8 Canon macro in terms of field of view, background blur, etc. At f/1.8 it won't blur the background quite as much as a similar full frame lens, but I find this is a bit of a blessing - I rarely actually want the shots where one eye is in focus - I want subject isolation, not dreamy pictures.
4. Focusing. With the MSC focusing it is very fast to focus, as well as being near silent in movies. It works well with tracking on my GH2, delivering in focus shots of my kids riding bikes towards me and so on.
5. Price. At $399 it is a good value compared to similar primes in other formats. The Canon 85mm f/1.8 is a similar lens on full frame, and has more problems wide open than this lens. Build quality is not as good, but it still feels solid and like it will last a long time.

Where this lens (and the 20mm Panasonic lens) will change how I operate is that the combination of primes gives me more creative range than with my zooms - but in the MFT format the total kit is so small I find I'm bringing them everywhere. That is making a big difference in my images - the subject isolation is much nicer than was possible with P&Ss, even fast aperture ones like the Fuji X10.

In short, I feel like this lens makes the MFT format a solid choice. Capable enough to deliver in almost all situations, yet small and cheap enough to mean you have the capable kit with you when the opportunity arises.

In terms of stock, I've had no problems getting images taken hand held in low light approved. As with any format, it ultimately comes down to the lens selection. I personally prefer more telephoto shots, and with the addition of this lens I'm happy!