Metabones speedboster for GH4 - which one?

[duarted]

Hi everyone,

I'm a little confused about the ammount of Metabones Speedbosters available and I want to make sure I'm making the right purchase.

I want the best speedbooster to use on a Gh4 with Canon lenses (mostly EF lenses)

Here are some that I found:

Metabones - Canon EF - Micro Four thirds Mount Adapter T Speed Booster XL 0.64x

Metabones - Canon EF - Micro Four thirds Mount Adapter Speed Booster

And there's a person selling the Metabones Speed Booster 0.71x Ef to Micro Four Thirds M43 version S

I'm a little confused and not sure what the differences are. can anyone help? thanks!