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Ef Eos R .71 speedbooster

New Contributor

Hey Forum fam!


 I bought a used speed booster and didn't realize it needed the assembly lock arms which did not come with my purchase. unfortunately, the parts won't be available until September and I am wondering if it is ok to use the adapter without the extra support arms. It seems to find just fine on the body of the c70 and I really don't want to wait until then to use it.

Thanks so much for your help.



Reputable Contributor

From what I understand, it's not required to use the locking arms.  However, what lens are you using?  If it's a very large/heavy lens, it may be best to install the locking arms to make things more stable/rigid.


EOS 5D IV, EF 50mm f/1.2L, EF 135mm f/2L, 600EX-RT (x6), ST-E3-RT
EOS C70, RF 24-70 f/2.8L IS