It was not so long ago when DSLRs were considered the first choice when it came to excellent image quality - perhaps the most important area of performance when it comes to more advanced cameras.
However, the recent raft of higher-end compact system cameras (CSCs) have upped the stakes in this regard and are now providing a very real alternative to their bulky counterparts.
So what's changed, and why are premium CSCs all of a sudden becoming such a tempting and viable alternative?
The quality of the images a camera produces is dependent on many factors, but ultimately it's the type of sensor and size of sensor used within that's key.
One of the most significant developments we've seen of late is the introduction of full frame sensors in CSCs, namely the Sony Alpha 7-series.
To fit such a large sensor inside such a small body is a remarkable technological achievement and the only compromise you'll have to make for opting for a full frame CSC is to use slightly larger and heavier lenses than those produced for CSCs with smaller Micro Four Thirds or APS-C sized sensors.
As an example Sony's FE 55mm f/1.8 ZA Carl Zeiss Sonnar T* lens for the Sony Alpha 7 is more than twice the weight of the Olympus 25mm f/1.8 M.ZUIKO lens that's equivalent to 50mm once the 2x crop factor has been taken into consideration.
With Sony being the only manufacturer to release a premium full frame compact system camera, it asks the question of how long it'll be until another manufacturer decides to release their own model to take on the competition?
MFT and APS-C
As things stand, the best premium CSCs come with full frame, APS-C or Micro Four Thirds sensors, and it's due to the fact that they're so much smaller, less bulky and considerably lighter that they're proving to be so popular as an alternative to a DSLR.
The main attraction isn't just the body size either, it comes down to CSC lenses being a fraction of the size of DSLR lenses and as a result it can lead to a lighter kitbag that's more comfortable to carry, but also gives you the option of pack more in a smaller space.
Three of the best CSCs we've individually tested in the last six months are the Sony Alpha A7, Olympus OM-D EM-1 and Fujifilm X-T1. Each camera features a different sized sensor, so it's time to put the trio to the test to find out how the image quality compares and determine which system offers the best value for money.