There is always speculation on the photographic internet as to who makes various sensors. In a way this is pretty irrelevant since who manufactures it isn't necessarily the most important thing. However, it seems that the Leica Q2 and the Panasonic S1R have the same basic sensor. Panasonic have a share in the Towerjazz company that makes sensors and Leica are in partnership with Panasonic and share technology so maybe that's who make it.
Whatever it's origins both cameras have an 8368 x 5584 sensor that gives a whopping 46MP (133 MB) file. At 300 PPI that's a 27 x 18 inch (70 x 47 cm) file. Just to get an idea of what thats like here's a comparison with an A3 page. (The A3 page is the inner rectangle)
As you can see these are file sizes that will handle the highest levels of print reproduction and also allow some serious cropping. In many ways current high resolution digital images are overkill. We have had the capacity to print huge 48 sheet street advertising posters for some time now. We are getting to the stage where we only need one lens for our cameras and other sizes can be cropped from that high-res image. And that is pretty much what the Leica Q2 offers.
Above are two files I shot with the Leica Q2 that I have on one of my picture library sites. As you will realise the bottom image is a crop from the top one. Upsized to around 11MP. In terms of image quality it's fine for the print and web reproduction required from a stock image. And yes if it was shot with a longer lens on an interchangeable lens camera it would be better quality, but then I would have to carry around a heavier and larger camera body and lens. The whole point of getting the Q2 was to avoid doing that.
Now obviously this doesn't work for everybody. Certainly sports and wildlife photographers wouldn't even consider doing this. But for what, how and where I shoot it works well for me. I can offer potential picture buyers compositional alternatives from the same image at a size and quality that they can use. The vast majority of stock images are used either for the web or for print requirements at less than A5 anyway. And even if a picture buyer wanted the bottom image for A3 reproduction, then it would work. I have sold some very small (5MP-8MP) files that have been used at A3 and they look really good when printed in magazines.
I'm not inclined to carry around heavy, large outfits and a selection of lenses anymore. That impacts on how far I can walk and where I can get to. I've had back issues for many years and I now have to manage that because it's not going to get any better. The lighter my camera, the longer I can keep doing what I do, it's as simple as that. So the Leica Q2 works for me. Now I'm currently bidding on a Leica C LUX 1" sensor compact camera on ebay which would handle the longer telephoto lengths without adding much to what I carry around. But I shoot mainly in the 28-100mm lens range anyway so the Leica Q2 will handle that with ease.
All of this is a long preamble leading to my belief that this sensor is the best I've ever used. I did use a Canon 5DS and 5DSR with 50MP sensors, but the Q2 sensor is better than either of those and certainly has a better lens in front of it. The Summilux 28mm f/1.7 lens on the Q2 is extraordinarily good. Sharp from corner to corner at all apertures. Using this at ISO 50 gives me ridiculously high quality files. As indicated above the huge files created using the 28mm setting will probably never be reproduced at full size from sales via my stock libraries, but they make serious cropping a real option. And below are some examples of what kind of cropping I can do with this sensor.
HIGH ISO
ISO 6400
ISO 12500
ISO 25000
ISO 50000
Above are the four highest ISO settings from 6400-50000. Given the size of the sensor and the pixel density these are quite remarkable. Even at ISO 50000 the image is still holding up. These are all taken from the in camera jpgs. I would have no hesitation in using the camera up to ISO 12500 and while the two highest settings are obviously noisier they are still sharp and the colour is still holding up. This just proves how far sensor technology has come over the past few years and how it makes the Leica Q2 into a true all round camera.
Finally, I've seen some criticisms of the colour of the camera jpgs. This comes from the usual suspects, YouTube 'reviewers'. As it often the case from these sources, it is complete BS. Below are four jpgs. straight from the camera. As you can see there is absolutely nothing wrong with the colour, even considering the top three were shot in mixed lighting.
