High-end compact cameras are designed to offer the controls and sometimes even the image quality of a digital SLR or mirrorless compact system camera – but it's not necessarily an either/or decision. Lots of photographers with SLRs will go looking for a smaller camera that will fit in a jacket pocket on occasions when their main camera would just be too bulky – but they still want a serious level of control and image quality.
The emphasis here is on larger, better sensors, high-quality lenses and lots of manual shooting options, and this is the area that's seen some really big changes recently.
Point-and-shoot compacts have a plethora of time-saving exposure presets and scene modes, and these are fine for those who don't have the time or the inclination to get involved in the technicalities.
But if you want to take creative control of your camera and try more advanced photographic effects, you need a camera that lets you select and adjust PASM exposure modes – these are Program mode, Aperture priority mode, Shutter priority (or Tv) mode and Manual.
Many advanced photographic techniques rely on being able to control the camera's shutter speed and lens aperture manually, and that's what these PASM modes do.
A high-end compact camera will also let you shoot 'raw' files as well as JPEGs. The JPEG format is fine for everyday use because the camera delivers a ready-made digital image you can share and edit straight away. But for the best possible quality you need access to the raw data saved by the camera's sensor. This creates much bigger files (you won't be able to store as many on the memory card) and you'll need to raw conversion software on your computer to turn them into editable images, but you will be able to get better quality from the camera.
Look out for cameras with viewfinders, too. You may be used to composing pictures on the screen on the back of the camera, or your smartphone, but apart from making you walk around like a glass-eyed zombie, they can be really hard to see in bright light.
Some high-end compacts have optical viewfinders, but these only work with relatively short zoom ranges. They can be quite cramped, with lots of distortion and don't always show the full area the camera will capture.
Increasingly, camera makers are using EVFs, or electronic viewfinders instead. Early examples looked grainy and responded sluggishly, but today's EVFs are sharp, bright and much more responsive.
High-end compacts with EVFs are more expensive and may be larger, but it's definitely a feature worth having.
Most of all, though, look out for the sensor size. Until recently, high-end compact cameras mostly used 1/1.7-inch sensors or thereabouts – large enough to offer a useful improvement in quality over regular point-and-shoot cameras, but a long way short of the sensors used in SLRs and compact system cameras.
But that's changed. Canon started the ball rolling with its PowerShot G1 X and a sensor just a tad smaller than APS-C, but this is a pretty expensive and bulky camera. Since then, Canon has launced the G7 x, a high-end compact with a 1-inch sensor roughly half way in size between normal compact camera sensors and those in SLRs.
For many, this will give the best of both worlds – a big jump in quality but a camera that's still small enough to slide into a pocket. Sony uses a 1-inch sensor in its excellent RX100 cameras.
Perhaps the most impressive technical advance, though, is in the Panasonic LX100, which has a Micro Four Thirds sensor. This is just a little smaller than APS-C and used in Panasonic and Olympus compact system cameras.
This is the other key area for high-end compacts – the lens is a key element of the package. Most come with a 3-4x zoom range, which is fine for everyday photography. But do look out for lenses with a wide maximum aperture – and one that stays wide across the whole zoom range. This will give better performance in low light and more attractive depth of field effects.
Really keen enthusiasts, however, may be prepared to sacrifice a zoom lens for a larger sensor. The retro-styled Fuji X100 series, for example, has an APS-C sensor and a fixed 35mm equivalent lens. You're more restricted in your compositions and you have to use your feet more, but many find a fixed focal length lens encourages better photography.