This obviously rather largely depends on what we’re comparing, but in terms of modern digital cameras, sizes vary enormously.
I dug up a tape measure and got to work…
I should mention that these images were stolen from Nikon Rumors – there’s are much better than mine…
These are my NIKON digital bodies, from the left a Z6ll, the Z8 and the Z9.
It’s not too surprising that there are small differences in size between different models, but in this example all three bodies house full frame (24×36) sensors, and even the Z6 and Z8 use the same battery.
So why the differences in size? The principal, and most obvious, is the size of the Z9 – this is mainly due to the integrated grip (which allows a much larger capacity battery).
Despite inaccuracies in my photo montage, the rear screens are all identical 3.2inch diagonal.
A new functionality in the Z8 (which will no doubt soon feature in a firmware update for the Z9 which has the same sensor) is Pixel Shift – this may account for NIKON needing a bit more room around the sensor mount.
The single most important factor for me is the ergonomics of any camera body. I personally can’t get used to Canon, but it’s the shape and button layout and not the capacity of the camera that puts me off. I wouldn’t ever say that I would NEVER be able to use a Canon camera, but after so many years with a NIKON in my hand, I’m used to where everything falls and I can use the camera without looking to see where things are. (To some extent this is moot as I only rarely use anything other than the on/off switch when I’m out and about with a camera !)
I suppose it’s back (again) to horses for courses – if you’re comfortable with the size, shape and weight, then where’s the problem? The increased capacity battery pack of the Z9 is a very positive advantage for some shooting situations, particularly when you have a days shooting a long way from a charging point.
As for size, the street photographers would obviously appreciate a smaller, more discrete, camera body. And I shouldn’t think landscape photographers cared one way or the other, given that for most of the time their cameras are mounted on a tripod.
On a personal level I have to say that in the past I prefered a larger DSLR camera body as I felt it absorbed the mirror vibrations etc. better. But given that two out of my three current bodies don’t even have shutters (or mirrors!) this is less of a concern.