Question about mirrorless

[AndyS]

5. I can't imagine what the issue might be.

Using a electronic viewfinder (EVF) allows the camera to boost gain in low light so if anything performance is much better in that respect. Image performance is a function of sensor and if it's a comarason of noise in high ISO 4/3 sensors are at a disadvantage but APS or full frame should be completely equivalent to the same sensor size regardless of viewing system.

The older EVFs were lower pixel count and the refresh rate was sometimes noticable (flicker) but anything in the last 5 years should be indistinguishable from SLR (except for the enhanced brightness).

As for the SLR sound AP switched to Sony to get rid of that distraction. Gone are the days of a press conference with the speech completely drown out by the flappity flap noise!

Edit to add: Making the switch is body only cost as an adapter will retro fit the body to legacy lenses. Nikon is the best in this respect as every Nikkor lens ever made can be brought along. Updating to newer optics for the more compact size and performance can come along as you wish.