For such a new system it sure has a lot of names; Mirrorless Interchangeable Lens Camera, Micro Four Thirds Camera and Electronic Viewfinder with Interchangeable Lens Camera or EVIL Camera (great acronym & my personal favorite). The first of its kind was the Panasonic G1 released in 2008. Currently Panasonic, Olympus, Sony and Samsung produce cameras of this variety and it is expected others will join. Basically, it combines the flexibility of a DSLR with the light weight of a point & shoot camera.
EVIL cameras all have a few things in common. Eliminating the bulky mirror box assembly allows Mirrorless cameras to have a much more compact size. Cameras of this type do not have a viewfinder (some have an optional accessory viewfinder that mounts onto the hot shoe). The sensor they all use is what is called a “micro four thirds†sensor. While it is not quite the same size as the APS sized sensors inside of many DSLRs, it is larger than what is inside Point & Shoot cameras. They also all have the capability to interchange lenses and have a larger selection of accessories.
At a price point that rivals entry level DSLRs, the size is an obvious advantage; pair the thin body with what is called a “pancake lens†and it’s possible to fit into a pocket. Because these cameras were built for the amateur/prosumer market, they are loaded with features including built in user guides. The accessories allow users to perform more advanced and complex photo techniques. And of course there is the sensor. It isn’t just megapixels that give you high quality image rendering, it’s also sensor size. Because it is a larger sensor, cameras of this type are able to produce comparable high quality images that DSLRs produce.
It isn’t a perfect though. Even though it does have a bigger sensor than Point & Shoots, contemporary DSLRs still have larger sensors that perform better at higher ISOs and in low light (DSLRs with what is called a full frame sensor are the best performing). Some may have trouble with the missing viewfinder. This is particularly a problematic when shooting outside during the day. Some models have accessories that can combat that issue. Another issue, which will admittedly solve itself once these products have been on the market for a while, is the lack of lens and accessory selection.
The biggest thing that stands out, to a technician anyhow, is the vulnerability of the image sensor. The shutter mechanism is interesting because it is a similar mechanism to that of DSLRs but its “resting†position is open instead of closed. What this means is that when lenses are interchanged the sensor is completely exposed. At least with DSLRs there is a shutter acting as a barrier between the sensor and everything. Because the sensor is exposed it is much more likely to get dust and because it is always exposed it is more likely that people will attempt to clean the sensor. You know what breaks the most on cameras? Anything a person can stick their fingers into.