And a large sensor DSLR system, with a long register distance, also needs large lenses, especially if the aperture or the zoom ratio is large.
Hence, among enthusiasts, there has been a desire for more compact large sensor cameras, to bring along more easily in a jacket pocket, for example. We have waited a long time for these types of cameras to arrive, and in the last years, we have gotten more to choose from.
To illustrate this trend, I have compiled this diagram of compact, premium cameras from the last decade. The measure I have used along the left axis is the imaging sensor size (in mm²), divided by the maximum aperture. The bigger this figure, the better.
In the case of a zoom lens, I have divided by the average over the long and short end maximum aperture, which is a bit unfair towards those with a longer zoom range, but life is unfair anyway.
Sensor area in mm² divided by maximum aperture size
In the case of a fullframe camera with an f/2 maximum lens, like the Sony RX1, the area of the sensor is 860mm², making the measure half of that, 430. This is plotted on a logarithmic scale in the picture above.
To the left, I have made some "base line" notes about what this measure becomes for a one inch (Nikon CX format), Micro Four Thirds, or APS-C mirrorless camera with a basic f/3.5-5.6 kit zoom lens, 25, 50, and 82, respectively.
Back ten years ago, Panasonic were king of this segment with their Lumix LX line of cameras, based around a 1/1.7'' sensor (8mm x 5mm). This was perfected with the Lumix LX7 in 2012, with a very impressive f/1.4-2.3 zoom lens.
However, then came the Sony RX100 line of cameras which changed everything. By putting a much larger 1'' sensor (13mm x 9mm) in an equally small camera, they could offer much better image quality. After this innovation from Sony in 2012, all premium compact cameras need to have at least a one inch sensor.
And Panasonic's answer was the Lumix LX100 in 2014. It uses the even larger Four Thirds sensor, but only uses about 80% of the sensor surface.
In the mean time, the first really large sensor'ed compact camera came from Sigma, the Sigma DP1 in 2006, with a near APS-C sensor size. However, with a maximum aperture of f/4, it didn't impress a lot. Also, the performance and user interface was much below expectations. The next iteration brought an f/2.8 lens, but at the expense of a larger size.
Even if Sigma has churned out a number of variations around this camera during the last ten years, none of them have made any significant impact. They are just too odd to catch on. The most recent Quattro series bring a strange shape, and with a unique sensor technology it promises very good colour rendition. However, it remains a niche camera.
In terms of the very large sensor compact, Fujifilm was the first to get a top seller with the Fujifilm X100 series in 2010. Combining a retro look with innovative technology, and a large APS-C sized sensor with an f/2 lens, it was an instant hit. The camera is still a bit large, though.
Nikon and Ricoh tried to target the same segment with their very similar Nikon Coolpix A and Ricoh GR. However, with a more limited f/2.8 lens and a steep price tag, they were never very popular, even if they have a smaller size.
Looking at the diagram, it is very clear why Canon discontinued their Powershot S series. It was just not competitive anymore, with the 1/1.7'' sensor. It has been superseded with a new line of one inch sensor cameras, where the Canon G5 X is the top dog. It even sports a built in EVF. Those who are into birds and wildlife photography should look at the Canon G3 X, with a 600mm equivalent long end.
The king of this camera class is the Sony RX1 mark 2, with a fullframe sensor and a 35mm f/2 lens. The second iteration of the camera brings a much wanted EVF, and improves the autofocus through the use of PDAF technology. One could still complain that this camera is a bit large and heavy, not to forget expensive.
I would expect this segment to continue to grow. Expect more premium large sensor compact cameras, as this is where the high margins are.
I still miss one specific camera type: The large sensor, large aperture, fixed focal, truly compact and reasonably priced camera, with an EVF. Perhaps the Ricoh GR is the closest so far (without the EVF), but I think there are a number of enthusiasts ready to buy this kind of camera when it arrives.