Re: tele extenders

[graywolf]

What happens is that all the aberrations of the lens are doubled along with the 
focal length, old cheap tele-converters add their own aberrations as well. Zooms 
tend to have more aberrations so they do not stand up to tele-converters as well 
as most primes. However most of the 2.8 zooms are very good and can stand up to 
the tele-converter quite well while cheaper zooms do not. However there is no 
help for the fact that if your lens is sharp at 16x but not higher 
magnifications with a 2x it will only do 8x. That is simple physics.

--

Andre Langevin wrote:

To those that have used a 2X tele-extender with a telephoto (200 or 
300mm), what do you seem to find to be the compromising element...loss 
of sharpness, contrast, etc?  When I used a 300/4A* with a 2x-AS I was 
always impressed with its results.  But now with another system I'm 
getting a slightly diffused image with a 70-200/2.8 and 2xEF, more so 
than I would have expected.


I've heard repeatedly that zoom don't marry well with tele-converters.  
There may be exception, i.e. when a zoom has a dedicated converter, but 
has there been a lot of them and are they really working fine?

Andre


--
graywolf
http://graywolfphoto.com/graywolf.html