Does the canon EF extender work with a 20D?

KathyD

KathyD

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Hi,
I'm looking to get either the 1.4x or 2.0x extender for my 20D to increase the length of my lenses as it seems to be a cheaper option than getting a longer lens; but I know that only some bits work with the 20D. Does anyone know if the canon extenders are Ok with this body?
Ta
Kx
 
In a word yes.;)

It all depends on the lens you are going to use regarding how well the AF will work though..:)
 
Hi Joe T,
I have the canon EF 75-300 USM, which is good - but want to have a longer length of around 420 or even 600 to zoom in on shy wildlife and my surfing buddies out at sea!
Kx
 
the ef extenders will only work with certain 'L' lenses Kathy - check the Canon EOS website, lenses section for compatibility.

There are thrid party extenders which work with any lens, albeit with a lesser IQ
 
As above only work on some lenses, the canon bodies will not AF above f4 so for your lens it will work up to a point (around 130mm if i remember right from the one i had) then you'll need to MF.

If you're happy using MF then it will work right up to 600mm with the 2x.
 
Thanks guys, looks like I've still got some researching to do! :bang: Will check out the EOS www after dinner........any recommendations on a good 3rd party make?
cheers again for the help!
 
ifotou said:
As above only work on some lenses, the canon bodies will not AF above f4 so for your lens it will work up to a point (around 130mm if i remember right from the one i had) then you'll need to MF.

If you're happy using MF then it will work right up to 600mm with the 2x.
Click to expand...

Not so:
All EOS bodies will auto focus to f/5.6 and the 1 series to f/8
 
Jonnyreb said:
Not so:
All EOS bodies will auto focus to f/5.6 and the 1 series to f/8
Click to expand...

really? i had the jessops 2x teleconverter and the same 75-300mm f4-5.6 III USM lens as above and it would not autofocus on my 20D smaller than f4. Actually states in the critieria that it will not auto-focus smaller than f4 due to canon bodies not allowing it.
 
ok is this when i get technical on this - please correct me if i'm wrong -

According to the Canon site on the 2x teleconverter -

"The effective aperture of the lens is increased by one or two stops respectively. Autofocusing does not operate if the effective maximum aperture is greater than f/5.6 (greater than f/8 on the EOS 1V and EOS 3)."

So that looks right what is said above by the guys about f5.6/f8...but please note that it is the "effective aperture" which is also increased, thus a f4 lens will be increased by one stop to f5.6 and will work fine.When the lens gets to around 135mm and moves to f5.6 it is effectively f8 and is thus outwith the operating range of the camera.

So teleconverters on anything other than the 1 series ones will only work up to f4 on the camera (effective f5.6)
 
ifotou said:
ok is this when i get technical on this - please correct me if i'm wrong -

According to the Canon site on the 2x teleconverter -

"The effective aperture of the lens is increased by one or two stops respectively. Autofocusing does not operate if the effective maximum aperture is greater than f/5.6 (greater than f/8 on the EOS 1V and EOS 3)."

So that looks right what is said above by the guys about f5.6/f8...but please note that it is the "effective aperture" which is also increased, thus a f4 lens will be increased by one stop to f5.6 and will work fine.When the lens gets to around 135mm and moves to f5.6 it is effectively f8 and is thus outwith the operating range of the camera.

So teleconverters on anything other than the 1 series ones will only work up to f4 on the camera (effective f5.6)
Click to expand...

What you say is spot on - you have to multiply the maximum widest aperture of the lens (not an issue with fixed f/ lenses!). I sense slidy goal posts in your argument, but the final debate is a good illustration;)
 
Jonnyreb said:
What you say is spot on - you have to multiply the maximum widest aperture of the lens (not an issue with fixed f/ lenses!). I sense slidy goal posts in your argument, but the final debate is a good illustration;)
Click to expand...

was trying to get the right words out :) lol
 
Hi guys,
Thanks for the techie stuff, most of which has gone straight over my head :thinking: AF is useful but not overly important.

I'm thinking that the extender's AF would work with my macro EFS 60mm f2.8 lens, as it would increase it by up to 1 or 2 stops to f4.0/f5.6 so still be within the camera's operating range thingy?

So would it still be a "macro" lens with the extender?:help:

Sorry if I sound like a numpty but if I don't ask, I'll never learn:amstupid:

Kx
 
lol - yes it would work and still be a macro :thumbs:

You'd have to get an extender that would accept an EFS lens - I'm not sure of any but I think DougDarter uses a Kenco (?) or similar
 
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