In the three years since Panasonic and Olympus launched their jointly-developed Micro Four Thirds standard, the interchangeable-lens compact system camera (CSC) market has gone from strength to strength and delivered some really interesting, high-performance cameras.
One of the main reasons the compact system market has proven so interesting is that there’s no over-arching standard for manufacturers to conform to, meaning they are free to develop their own interchangeable-lens mirrorless systems as they see fit.
This has resulted in a number of different approaches, all of which use differently sized sensors: Micro Four Thirds cameras from Panasonic and Olympus use a 17.3 x 14mm chip; Pentax has recently announced it will be using a 5.7 x 4.2mm (1/2.3in) compact-sized sensor for its new Q camera; Samsung and Sony, meanwhile, use 23.6 x 15.8mm APS-C-sized sensors for their respective compact system offerings. Quite what Nikon and Canon will come up with when they finally decide to enter the mirrorless market is anyone's guess.
Why does any of this matter? Simply because larger sensors have a greater potential to deliver better image quality than smaller ones do. Of course that doesn’t mean that they always do as there are other factors involved, but more often than not when faced with the same scene the camera with the biggest sensor will get the best shot, especially if light levels are low.
That’s not to say that anything less than Full Frame (24 x 36mm) will deliver poor image quality – far from it. Indeed, our endorsement of the Lumix G3 shows that Four Thirds sensors can more than hold their own against APS-C. Crucially though, there’s a huge leap in quality between regular 1/2.3in compact-sized sensors and the larger Four Thirds and APS-C sensors sported by compact system cameras.