How severe must be the mis-alignment be to be considered an issue? I noticed my dslr have a 2mm bias at the left compared to the right. What i did was to photograph a ruler(on my monitor) and aligning a centimetre mark to the left and right border of my VF. Photo shows 2mm more tha the right's.I.e 15cm and 29cm comes out as 14.6cm and 29.2cm
Blame me for being paranoid, but this was because i did a cotton bud delicate cleaning on my mirror, and the next cleaning on the focusing screen almost went awry when the cotton bud apparently caught on the black rectangle sponge thing! Thank goodness managed to remove it but just want to make sure mirror's fine.