Microadjustment
 

I have a Canon 7DMKII and use a Canon 300mm f2.8 lens with a 2x converter, what's the best way to about microadjusting the lens?

Thanks Geoff

The "dot Tune" method is well received by many photographers.
http://www.fredmiranda.com/forum/topic/1187247

However I got better results with Reikan software. This is not freeware, The standard version for lenses up to 400mm costs £20.
http://www.reikan.co.uk/focalweb/

There are other methods if you care to search for them.

Harry