View Full Version : Use of Canon lenses on m43

Mrs T
29th April 2012, 08:43 PM
My father was rather taken with the E-M5 when I let him have a look this weekend. He has a question which I cannot answer and I hope someone on this forum can. He is a Canon user and he wants to know whether he could use his favourite lens on the Olympus and what functionality could he expect i.e focus/exposure if any.

His favourite lens by the way is the EF 70-200mm 1:4 L IS USM.

Thank you,


1st May 2012, 09:23 AM
There seem to be a number of EF to m43 adaptors out there, ranging from very cheap to quite expensive. However, only the very expensive will control aperature, and none of them (that I could quickly find) offer AF. So, apart from using the lens wide open, it may be cheaper to spend the money on some new glass..

1st May 2012, 09:57 AM
I am not aware of any (though I am happy to be corrected) non 4/3 lenses that will provide AF and auto-exposure functionality. The electronics and associated controls are simply not the same on other lens mounts to those on 4/3.

If you plan on using any non 4/3 lens on a 4/3 camera with an adapter, you will need to use manual focus (you still get focus assist though - the green dot and beep) and you will have to manually adjust the aperture though the camera will still provide you with an indication of what the correct exposure should be. It's all manual though... which isn't really such a bad thing. In fact, it could be positively uplifting.

1st May 2012, 11:09 AM
Exposure is available on at least one very expensive adaptor (costs more than most m43 cameras though!), but agreed I can't find any adaptors for EOS EF lenses that allow AF on any other bodies (not just m43).

Mrs T
1st May 2012, 08:18 PM
Hi Swing and John,

Thank you very much for your replies, both are very useful and I appreciate you taking the time to help.

Hopefully we might get a convert to Olympus! I can tell he's very tempted.


1st May 2012, 08:41 PM
As a novice m43 user i'm no expert, but will that lens become a 140-400mm f2.8 due to the crop factor?

1st May 2012, 09:00 PM
As a novice m43 user i'm no expert, but will that lens become a 140-400mm f2.8 due to the crop factor?

Yes it will. However on a Canon DSLR with an APS-C sensor which has a crop factor of 1.6 it will be a 112-320mm.


Mrs T
2nd May 2012, 07:59 PM
Pete and Peter,

Thanks for the additional information.


5th May 2012, 04:33 PM
I have the Ef/m43 adaptor and the 70-200 f4 lens...using the adaptor the lens is fixed wide open at f4, so using manual exposure I have to adjust shutter speed and focus is manual of course. For the price of the adaptor its worth being able to use your EF lenses - but its not a solution for every-day use in my opinion

Mrs T
5th May 2012, 04:36 PM
Hi Brian,

Thanks for taking the time to share this information.