Which mount adapter, EF-EOS R or M, can I use for EOS 1DX Mark III?

[StraightShooter]

I just bought the Canon EOS 1DX Mark III, and have an EF camera (1 red circle on lens mount). According to Canon's site, I should use EF-EOS R or M. https://www.canon-europe.com/lenses/tech-guide/compatibility/

I don't know which mount adapter to use, unless I'm misunderstanding and I can use either.

[deebatman316]

Hi Trevor there is a mistake in the chart pertaining to EF-M lenses being compatible with an adapter on an APS-C DSLR.

-Demetrius

40D, 5D IV, EF 16-35mm F/2.8L III, EF 24-70mm F/2.8L II, EF 28-135mm F/3.5-5.6 IS USM, EF 50 F/1.8 STM

430EX III-RT & 600EX II-RT

[Tronhard]

Thank you Demetrius, already corrected, but thanks for finding it and letting me know! Hopefully all sorted now.

[deebatman316]

Hey we all make mistakes especially if we're trying to make compatibility charts on the fly.

-Demetrius

40D, 5D IV, EF 16-35mm F/2.8L III, EF 24-70mm F/2.8L II, EF 28-135mm F/3.5-5.6 IS USM, EF 50 F/1.8 STM

430EX III-RT & 600EX II-RT

[Tronhard]

I've been having a few challenges lately.  I am being treated for cancer and it seems to have spawned a stroke as well.  I try my best to check, but sometimes I miss things.  I do welcome any corrections that folks find - I'm not too proud to be corrected!

[Lotus7]

Good catch!  Wonder who prepared that chart?  That A should be a N. 

Physically it's not possible optically without the use of relatively expensive relay or GRIN optics whose expense would make such an adapter financially not viable. EOS M lenses have a very short 18 mm flange/sensor distance which just doesn't work with the 44 mm APS-C DSLRs flange distance.

[Tronhard]

Better late than never!  I made the chart on the fly, so the error was mine, but I fixed the error (thanks to all again for spotting that), and hopefully there are no further corrections!

[ebiggs1]

Trevor I haven't had a stroke ...yet, BTW I certainly hope you make a full recovery, and had trouble following the OP's post.

"I just bought the Canon EOS 1DX Mark III, and have an EF camera ..."

My understanding is he owns a 1DX Mk III. My question is, you bought a $6500 dollar camera and don't know what lenses it uses?

[Lotus7]

EB: "My question is, you bought a $6500 dollar camera and don't know what lenses it uses?"

WHAT?  $6500 for a camera, and you're saying he/she has to buy something called a "lens" too?😊

(sorry - couldn't resist)

[ebiggs1]

I heard that somewhere.

[Tronhard]

Thanks for your kind words Ernie.   I am determined to get past this, but I shall likely have the odd SNAFU from time to time! 🙄