2x 111 extender

[billboman99]

Is there any point getting a 2x extender 111 for a 70-200 f4 ?

I have a 5D Mark 4. Would the AF work ?  90 plus percent outdoor shooting. F8 too slow ?

Thanks 

[Waddizzle]

The AF will still work, but AF performance will be compromised.  The Full User Guide for the cameras explains “Lens Groups” in detail.

The 2x extender fill cause the maximum aperture to change from f/4 to f/8.  In this mode you will have only one active AF point, the center AF point.  Because of the reduction in light reaching the AF sensor, focusing speed will take a noticeable hit.  Many people think something is wrong with the camera, forgetting that this is a side effect of using an extender.

[billboman99]

Thanks for the info. Doesn’t sound like it’s a good choice

[jrhoffman75 · Accepted solution]

I ran an informal test with my 1DX Mark III and 70-200 f/4 IS II lens. Used 1.4X and 2X extenders and compared prints that were of images with the extenders and similar prints cropped in Lightroom to same area coverage. I could not see the difference between prints at 13x19 size. 

With the new AI based software like Topaz Gigapixel or OnOne Resize AI I believe that the negative effects of extenders are not worth it. 

[billboman99]

Thanks for the info. That settled the issue.

[Waddizzle]

Be aware that when I spoke about AF performance taking a hit, I was not referring to image quality.  I was referring to AF speed.  Focusing at f/8 will seem sluggish.

[billboman99]

I think I might rent one to see the AF speed reduction. Thanks for the clarification.

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