EF 70-200mm has no autofocus with EF 2.0x II Extender

[murdocda]

I was gifted 2 Canon extenders 1.4x II and 2.0x II from a close friend who has passed. The 1.4 works great but the Auto Focus on the 2.0 does not work. I have cleaned the contacts which did not work. does anyone have any suggestions? Can it be repaired? Do I just toss it?

I would really like to keep and use this extender, coming from a friend.

Can any offer any suggestions?

Dave

[Waddizzle]

Sorry to hear about your friend.  What camera body and lens(es) are you trying to use with them?

The performance of teleconverters is entirely dependent on a few factors.  The camera and lens models, as well as the revisions of the teleconverters.

For cameras that support the use of teleconverters with select lenses, download a copy of the full user guide and search for the phrase “lens group.”  You should find a comprehensive explanation and guide on how to match up your gear. 

[Stephen]

Hello!

The extenders don't have auto focus. When paired with compatible lenses, they pass the information along, and let the camera know it's using {this lens} with {this extender} so it knows how to apply the exposure and focusing information appropriately. If your lens isn't "fast" or "bright" enough, the 2x extender won't be able to focus. I don't think the "manual" (it's a single page) is available online anymore, so I've attached it. 
Here is the rundown of officially supported lenses:

[p4pictures]

Many older DSLR cameras need a lens with an aperture that is f/5.6 or faster to focus. Their AF sensor is the limiting factor. With a 2x extender fitted to an EF 100-400mm f/4.5-5.6 lens the effective aperture would be f/9 to f/11 and so focus is not posible. 

Some of the last generations of DSLR were able to focus with f/8 aperture lenses or lens + extender combinations. For example EOS 7D Mark II / 80D / 5D Mark IV and EOS-1D X models all have at least a centre AF point that focuses with f/8 aperture. 

[johnrmoyer]

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@p4pictures wrote:

Many older DSLR cameras need a lens with an aperture that is f/5.6 or faster to focus. Their AF sensor is the limiting factor. With a 2x extender fitted to an EF 100-400mm f/4.5-5.6 lens the effective aperture would be f/9 to f/11 and so focus is not posible. 

Some of the last generations of DSLR were able to focus with f/8 aperture lenses or lens + extender combinations. For example EOS 7D Mark II / 80D / 5D Mark IV and EOS-1D X models all have at least a centre AF point that focuses with f/8 aperture. 

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And my EOS 80D will autofocus at F/11 in live view mode. So, it auto focuses in bright sunlight with a 2x on a lens that is F/5.6 in live view mode.

[jrhoffman75]

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@johnrmoyer wrote:

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@p4pictures wrote:

Many older DSLR cameras need a lens with an aperture that is f/5.6 or faster to focus. Their AF sensor is the limiting factor. With a 2x extender fitted to an EF 100-400mm f/4.5-5.6 lens the effective aperture would be f/9 to f/11 and so focus is not posible. 

Some of the last generations of DSLR were able to focus with f/8 aperture lenses or lens + extender combinations. For example EOS 7D Mark II / 80D / 5D Mark IV and EOS-1D X models all have at least a centre AF point that focuses with f/8 aperture. 

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And my EOS 80D will autofocus at F/11 in live view mode. So, it auto focuses in bright sunlight with a 2x on a lens that is F/5.6 in live view mode.

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Sensor focusing (Live View and mirrorless) don't have the aperture limitation. That is why some of the RF lenses have small fixed apertures. 

[murdocda]

Thanks for replying,

I have an EOS T5 using an EF70-200 Telephoto lens.

Dave

[murdocda]

I am using the EF 70-200 lens which is listed in your chart.

Dave

[murdocda]

I have an EOS T5 using an EF70-200 Telephoto lens. I have tried to use the 2.0 extender in the bright Florida sun with no joy.

Dave

[jrhoffman75]

Was it the f/2.8 70-200?