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New Contributor
Posts: 1
Registered: ‎09-09-2013

Canon 300 2.8 stops focusing

I have a used Canon 300 2.8 non is that I bought used. Tack sharp, great lens. But if you change from horizontal to vertical, it shuts off. in the repair shop now, they can't figure it out. any thoughts?

Posts: 11,674
Registered: ‎12-07-2012

Re: Canon 300 2.8 stops focusing

Yes, send it to CPS.

EOS 1DX and 1D Mk IV and several lenses!
Posts: 108
Topics: 1
Kudos: 22
Solutions: 3
Registered: ‎10-17-2012

Re: Canon 300 2.8 stops focusing

Sounds like it might be a fault with the AF/MF switch or the wiring so that it is switching without you moving the tab. Canon service would be your best bet.

Esteemed Contributor
Posts: 3,816
Registered: ‎06-11-2013

Re: Canon 300 2.8 stops focusing

Ouch... I happen to own one of these and can vouch for the fact that it is _not_ supposed to shut off AF when you rotate it.


If the shop can't figure it out... I'm wondering who you sent it to.  Is this at a Canon repair facility??



Tim Campbell
5D III, 5D IV, 60Da
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