Canon Extender EF 1.4X III: I am considering a purchase of the above extender for my Canon EF 70-200 F/4 lens and Canon 5D Mark iii. However, I am not sure if using this extender with...

IzzyKap Loc: Rockville, MD

I am considering a purchase of the above extender for my Canon EF 70-200 F/4 lens and Canon 5D Mark iii. However, I am not sure if using this extender with that lens will still allow use of autofocus. I think that I've heard and/or read somewhere that there is a problem with autofocus when using the extender beyond f/5.6. Any information in this regard would be greatly appreciated.

haroldross Loc: Walthill, Nebraska

I have had no issues with the AF while using that lens, extender, and camera combination. The AF is a slight bit slower but nat so much that you would really notice it.

SharpShooter Loc: NorCal

IzzyKap wrote:

I am considering a purchase of the above extender for my Canon EF 70-200 F/4 lens and Canon 5D Mark iii. However, I am not sure if using this extender with that lens will still allow use of autofocus. I think that I've heard and/or read somewhere that there is a problem with autofocus when using the extender beyond f/5.6. Any information in this regard would be greatly appreciated.

Izzy, yes you can use the 1.4 on that 70-200 very well. With your 5lll you could also use the 2x with no AF issues! Good luck ;-)
SS

CHG_CANON Loc: the Windy City

The 1.4III is a nice addition to every supported EF lens. Your 5DIII will auto focus for all supported lenses even those that take the aperture to f/8 such as the 100-400 f/5.6. This is the case for 1D series bodies and the 5DIII and now the 7DII but not other Canon bodies.

IzzyKap Loc: Rockville, MD

Thank you SharpShooter. That's good to know.Happy Thanksgiving!

SharpShooter wrote:

Izzy, yes you can use the 1.4 on that 70-200 very well. With your 5lll you could also use the 2x with no AF issues! Good luck ;-)
SS

IzzyKap Loc: Rockville, MD

Thank you for your helpful information.

CHG_CANON wrote:

The 1.4III is a nice addition to every supported EF lens. Your 5DIII will auto focus for all supported lenses even those that take the aperture to f/8 such as the 100-400 f/5.6. This is the case for 1D series bodies and the 5DIII and now the 7DII but not other Canon bodies.

HowardPepper Loc: Palm Coast, FL

Thanks for the information all of you. I also plan on purchasing the 1.4III for my 70-200mm f/4L on my 6D.

pbfcpa Loc: Central Maryland, USA

I just purchased the 1.4 extender to use with the Canon 70D and the 70-200 F4 L lens and it works great. No problem with autofocus. Bought it on sale two weeks ago for $432. Enjoy it.

imagemeister Loc: mid east Florida

CHG_CANON wrote:

The 1.4III is a nice addition to every supported EF lens. Your 5DIII will auto focus for all supported lenses even those that take the aperture to f/8 such as the 100-400 f/5.6. This is the case for 1D series bodies and the 5DIII and now the 7DII but not other Canon bodies.

So, the 7D II will AF at f8 ??

CHG_CANON Loc: the Windy City

imagemeister wrote:

So, the 7D II will AF at f8 ??

Yes, one if its more important features in my eyes.

amfoto1 Loc: San Jose, Calif. USA

pbfcpa wrote:

I just purchased the 1.4 extender to use with the Canon 70D and the 70-200 F4 L lens and it works great. No problem with autofocus. Bought it on sale two weeks ago for $432. Enjoy it.

It should work... 70D is an f5.6 limited camera. f4 lens with a 1.4X makes for an f5.6 combo. You might be limited to using only one or a few of the center AF points.

It will certainly work fine on a 5DIII.

On the other hand, a 2X that loses two stop of light making an f4 lens an f8 combo is another matter. Wouldn't work on a 70D, but will on 5DIII.

7DII, 5DIII, 1D series cameras are the only f8 capable DSLRs (EOS-3 and 1V were the f8 capable film cameras).

imagemeister Loc: mid east Florida

CHG_CANON wrote:

Yes, one if its more important features in my eyes.

YES, mine too !

Basil Loc: New Mexico

IzzyKap wrote:

I am considering a purchase of the above extender for my Canon EF 70-200 F/4 lens and Canon 5D Mark iii. However, I am not sure if using this extender with that lens will still allow use of autofocus. I think that I've heard and/or read somewhere that there is a problem with autofocus when using the extender beyond f/5.6. Any information in this regard would be greatly appreciated.

On my 7D, the limit was 5.6. At f5.6 it would focus (AF) on center AF point. The new 7D Mk II which I just bought will allow center-point AF at f8., which is great!