They come in a bewildering array of shapes, sizes and prices, so how do you choose the best CSC (compact system camera)?
We've produced this guide to explain how mirrorless compact system cameras work and how to choose the right one for you. Our camera home page will keep you up to date with all the latest camera reviews, but here's where we explain how to find the best CSC for you and what you need to look for.
Alternatively, if you already know the best CSC type for your needs, you can go straight to our top 5 lists:
- Best mirrorless compact system cameras for beginners
- Best mid-range mirrorless compact system camera
- Best advanced mirrorless compact system camera
Compact system cameras vs D-SLRs
The big appeal CSCs is that you can also change lenses and enjoy cutting-edge imaging performance, but with a much smaller and lighter camera body. So they offer SLR-like versatility in a more streamlined and discreet package.
CSCs are also known as mirrorless cameras because they don't have the reflex mirror and optical pentaprism or pentamirror viewfinder of SLRs. Instead, the live image captured by the image sensor is fed to the LCD display, just as it is with a compact digital camera.
In fact it's this basic similarity to a compact camera that makes CSCs attractive to beginners who want to take a step up. DSLRs can appear daunting, but compact system cameras for beginners have the same kind of viewing system and automated modes that novices are used to.
Compact system cameras are at a slight disadvantage compared to DSLRs for autofocus performance. With the DSLR design, a dedicated autofocus module checks the focus before you shoot, using fast 'phase-detection' AF technology.
This relies on the flip-up mirror of the DSLR design, and compact system cameras don't have this. Instead, they have to use the image on the sensor itself to focus, using so-called 'contrast' AF. This is precise, but much slower than the phase-detection autofocus systems used on digital SLRs.
Recently, though, manufacturers like Fuji, Sony and Olympus have been adding phase-detection capability to their camera sensors, so the gap in autofocus performance with the best CSC cameras is closing rapidly.
It's not always easy to see an LCD screen in bright light, however, which is why many compact system cameras also have electronic viewfinders (EVFs). These are miniature LCD screens which you view through an eyepiece. You find EVFs on more advanced compact system cameras.
These can be on the top of the camera, which makes it look just like a regular DSLR, or placed in the top corner of the camera body. The DSLR design is probably more intuitive for most users, but it makes for a bigger camera.
Otherwise, compact system cameras offer the same buying decisions as digital SLRs. The key factors are the user level (novice, enthusiast, expert), the sensor size and resolution and the lens fitting. Each manufacturer uses its own bespoke lens mount, so it's a good idea to check to range and cost of the lenses available before choosing a camera. The best CSC isn't necessarily the camera with the biggest specs, but the one with the right range of lenses.
As with other types of camera, the sensor size is the most important factor for image quality, followed by the resolution (in megapixels).
Until recently, most compact system cameras used either Micro Four Thirds sensors or APS-C sensors.
The Micro Four Thirds format was developed jointly by Olympus and Panasonic and is used in all their compact system cameras. It's a little smaller than APS-C, but the image quality is still very high and it does mean that the cameras and lenses are more compact.