1, Nikon is a more mature camera manufacturer. Their equipment, especially pro-grade, are more resistant to dust and moisture, both bodies and lenses. Sony, now playing with the big-boys, is starting to realize what it takes to be a top-tier camera manufacturer.
2, The mirrorless digital sensors, mostly until recent models, were just exposed to the world when the lens was removed, not hidden behind a mirror or shutter.
3, The sensor cleaning 'shake' option of many DSLRs executes automatically at shutdown, start-up and / or both. My Sony a7II does not have this auto-function.
4, If you change lenses with the camera 'on', the sensor is more likely to attract dust. This applies to all digital cameras.
Several observations: br br 1, Nikon is a more ma... (show quote
Your #1 is total bunk, LOL
I have used the best from Nikon, Canon, Sony and I get no more dust on my sensors with Sony than any other brand.
A few observations and recommendations from an ole pro at this. I also pass on these tips to my hundreds of photo students I have taught over the years in my Photojournalism, and Digital Photography courses at a state university.
ALWAYS also blow out the rear of your lenses (while holding the lens rear facing towards the ground) before mounting them. A lot of dust and stuff can hang out there, just waiting for you to mount that lens and power on your camera, attracting that dust right from the back of your lens to the sensor.
ALWAYS blow out your camera with the lens opening facing towards the ground, so any dust or debris falls out and NOT back into your camera and sensor.
ALWAYS blow out your lens caps and camera body caps also, as dust hides inside them too, just waiting to migrate to your sensor.
ALWAYS change lenses with the camera lens mount facing towards the ground and after blowing out the rear of the lens, quickly mount the lens, while shielding the lens and camera from any blowing wind, using your body or any structure.
ALWAYS change lenses with your camera turned off, as when your camera is turned on, your sensor is charged and can attract dust like a magnet.
ALWAYS clean off your lenses and cameras before storing them away ,and when you take them out of storage before use as they can pick up dust from inside camera bags and cases.
The shorter flange distance with mirrorless cameras means that image sensor is much closer to the mount opening , and as such is more exposed to any floating dust.
Shutter close or shutter barrier features in cameras just add another surface to collect dust and transmit it to your sensor when retracted or engaged. I dont bother.
I use my gear in all indoor and outdoor shoots, in dusty, sandy, dirty, including desert and beach environments around the world. And I change lenses in the field all the time, even if need be in windy conditions, yet I really dont have a dirt or dust problem with the sensors of my Sony cameras. I often can go six months and even a year before I need to do a minor sensor cleaning with my Sony A1, A7RIV, A7SIII.
My methods work for me, they can work for you too.
Cheers and best to you all.