All of the above were taken with a Canon 5Ds 50MP Full-Frame DSLR and the somewhat incongruous 40mm f/2.8 'pancake' lens. A very small lens on a very large body.
The 40mm lens is way better than anyone would assume it was. There is a great review of it by Roger Cicala on the Lens Rental Blog and the heading says it all - Canon 40mm Pancake - How Did They Do That?? which says it all really. 'Pancake' lenses are not known for their edge to edge sharpness, lack of distortion and crispness wide open, but this lens has all that. And at just over £100, it's an absolute steal. I spent the whole day yesterday with it on the 5Ds and the combination coped with sunlight, overcast light and a spell indoors when I was shooting in a gloomy stately home at mostly ISO 6400. And I came back with one of the best set of images, from an image quality standpoint, I've produced in a long time. Those 50MP sure help.
And this 40mm lens is a very good with those, because this little wonder takes advantage of all those pixels on the 5Ds. The myth is that large sensors with lots of pixels need high quality (which of course to many means a high price) lenses. Now that is in fact not true, because high pixel count sensors are actually very forgiving when it comes to cheap(er) lenses and these days there are very few downright bad lenses anyway, but the assumption is there. However, I can catergorically state that this 40mm f/2.8 is the one of the best best Canon lens I've ever used and considering it's size, price and type that's a pretty amazing statement.
Of course the Sony FE system has something similar. The small light Zeiss badged 35mm f/2.8. But that costs around £500 and the Canon cost me £118. I also think that the Canon lens is sharper. Again regular readers will know that 40mm is my favourite focal length anyway, so this is a really good buy as far as I'm concerned and it's the possibility of using lenses like this that has made me an ex-Sony FE user. I just have so much more choice with other systems.
I would also mention how good the indoor shots above at ISO 6400 look. This camera is certainly not regarded as a low-light specialist, but it's actually pretty good. The images are sharp, have great colour and are certainly less noisy than I was expecting. So the 5Ds is turning out to be more of an all rounder than I would initially have expected. I'm really glad I bought that too.