This sucker is massive. Although this produces the nicest edges of any TC I have tested yet, the reality is that between the weight and size I would say this is not practical to use as a TC. It's also heavy enough that the lens coming free of the hood mount is a real concern (happened to me once when it was apparently not fully threaded in, lens was happily caught).

Note it would vignette a little less if you have a 46-62mm step-up ring, this shot was taken with two step-up rings stacked to reach 62mm.