Just a question for those who actually tried this. How is it performing. The most important question here is how it performs at night (with stars) versus coma, CA and sharpness (corners, presume center will be ok).
Real life examples would be welcome. Didn’t find much found on the web so presume it must not be so good.
Not interested in propositions to use other lenses...just FF-lens + speedbooster on a6000 or other aXXXX.