I was looking at some micro four thirds camera to buy. I am not too sure how the whole system works:
- Can I use four thirds lens on micro four thirds camera? And the opposite?
- What brands make micro four thirds/four thirds cameras?
You can use a Micro Four-Thirds lens on a Micro Four-Thirds camera and they are compatible between manufacturers, so Zuiko, Olympus, Panasonic, Leica, Sigma and Samyang lens are all compatible with cameras from Olympus and Panasonic as long as the mounts are Micro Four-Thirds.
You can use a Four-Thirds lens on a Micro Four-Thirds camera with an adapter which must be purchased separately. There are a few options but if you have a weather-sealed Micro Four-Thirds camera and a weather-sealed Four-Thirds lens, you must buy the Weather-Sealed adapter from Olympus to keep the whole system weather-sealed.
It is NOT possible to put a Micro Four-Thirds lens on a Four-Thirds camera because it needs to be mounted closer to the sensor than possible for it to focus properly.
Don't forget about the range of lenses available to you. This site will show you all the brands involved with mFT.
Also, just a side note about fitting FT lenses onto mFT bodies, the auto-focus isn't as efficient (as FT on FT). This is because FT uses Phase Detection while mFT uses Contrast Detection.
There appears to be news floating around that Olympus plan to release a body that resolves this issue effectively. My guess is that it will be a mTF body with a Phae Detection intergrated sensor.