----- Original Message -----
From: "Tom Williams" <[EMAIL PROTECTED]>
> I am thinking of buying a 1.4X or 2X extender for my 100-400 IS. It will
> be used with a A2 body. My understanding is the 1.4X will cost me one
> stop, my max aperture would go from f/4.5 to f/5.6 and the 2X would cost
me
> 2 stops, f/4.5 to f/8? Is this right? And I understand that with my A2 I
> would not have AF. How do they effect metering? How about maintaining
the
> lens IS function? Anything else I should know about these to help me
decide?
>
Tom
You will lose both AF and IS with the A2 when putting any extender on it.
Metering is not affected. The only lenses for which metering is affected
with the converters are the older super telephotos (400/2.8, 500/4.5, 600/4)
The f-stops become f6.7 and f9.5 respectively for the max but it is
displayed correctly by the camera with the Canon converters.
I don't agree with the advice to go with Tamron/Sigma etc. The savings you
make now will be hard-felt later if you try and sell it again (third party
lenses have low resale value) and chances are good of having compatibility
problems in future with newer camera bodies. With the Canon you will feel
the pain only once. If you read the archives you will see lots of posts of
people complaining that their third party lens stopped working when they
tried it on their new camera and it had to be upgraded by the manufacturers.
The 100-400 is not a stellar performer with converters on, so it will pay to
get the best quality you can buy (the EF1.4xII)
My Opinion
Regards
Thys
---------------------------------------------------------
Thys van der Merwe
Portfolio of African Images:
http://home.mweb.co.za/te/teknovis
-----------------------------------------------------------
*
****
*******
***********************************************************
* For list instructions, including unsubscribe, see:
* http://www.a1.nl/phomepag/markerink/eos_list.htm
***********************************************************
