# Metabones



## colin.davis (Sep 1, 2014)

Hey CR Team,

I tried searching this in the forums, but couldn't effectively isolate my question.

Metabones speed booster ultra

http://www.metabones.com/products/details/MB_SPEF-E-BM2

Its idea is to increase the amount of light and reduce CA, vignetting, etc blah blah blah

So for a 24-70 2.8, it changes it to a 17-50 F2.

Is this a legitimate accessory to have, especially while travelling so don't need a dedicated wide angle lens.
I am assuming not because otherwise no one would buy 16-35/17-40, but just wondering if anyone had any experience at all with them

Thanks guys & girls


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