Extender for Canon 70-300L

Grumps1974

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Martin
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I have recently bought a Canon 70-300L and I have been reading various comments about using a 1.4 extender with this lens. From my research there are mixed messages about whether a Canon 1.4 extender will work with this lens. Some comments suggest that the extender can work with some adaptation and others say that the Canon 1.4 is not compatible. The comments suggest that a Kenko 1.4 is compatible but having used that extender in the past I know it does soften images significantly.

Can anyone throw any light on this for me please. I do not want to spend money unnecessarily.

Thanks.
 
From what I remember the Canon extender will fit on the lens but when you try and zoom the lens over its full range the rear element of the lens hits the front of the extender.
 
I think Gary is right. It's also affected by focus distance - with then lens at infinity I recall that the elements clash. The Kenko works because it doesn't have the protruding element. Be aware that with a 1.4, you will be working at f8 and may not get AF.
 
Yes, you can use the Canon TC at the long end of the zoom range, but cant zoom too far back out without damage. I guess the whole reason for using it is for more reach so as long as you are careful it will work, Ive seen at least one person put tape over the zoom ring to stop any accidents.

I use the Kenko x1.4TC with my 70-300L and dont find it softens too much. It's certainly good enough for shots that i dont pixel peep. A mate has the Canon x2 mkiii and i dont see much difference in quality drop when i used that with my 70-200.

There does seem to be more than one model. Mine is the latest version, the DGX. The only issue ive had is with my 80D. Just with this one lens. The exposure is very hit or miss with this combo, it tend to over expose quite a bit on certain scenes. No issues at all on my 5Dmkiii.
 
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Thanks for the contributions so far. They seem to sum up the conclusions I reached from my research.

I was aware of the impact of fitting an extender on the aperture but I am hoping my 5D mkIII would still let me autofocus.

So I guess the Canon is out. I am still not convinced by the Kenko but if I see a DGX at a decent price I will give it a go. If it does not produce the desired results I can always sell it.:)
 
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