In article ,
Whisky-dave wrote:

Focusing with a mirrorless

Cameras don't use the mirrors to focus the image,

slrs have a secondary mirror behind the main mirror for the autofocus
system to work, which has its own sensor.

mirrorless focus using the main sensor.

Really, when I focus my M3 I use the focusing ring on the lens for manual
focus.

whooooooosh.

Gone right over yuor head hasn;t it, why do they but IR markings on lenes and
this gose back well before mirrorless are yuo really climing that IR light
focussess differntly for mirrorless cameras ?

whoooooosh even higher.

plus, modern lenses don't have ir markers anymore.