Tele Converter Question

[Image-Rich]

Although this has been covered many times, I've been searching through the threads and cannot find a clear answer :shrug:

I have a Canon 40d body and currently use a Sigma 70-200m F2.8 for a lot of motorsport photography

When choosing a 1.4x TC should i get a Canon or a Sigma ? Or will both be ok?

I read that the Canon ones are designed for the prime lens therefore you loose the AF ? :shrug:

 

[Les McLean]

I use a sigma 1.4TC with a Sigma 70-200 F2.8 and it's a good combo, I use it on a 1D MKII, but did use it with a 40D, and worked well also.

Not sure about canon tc with sigma lens.

 

[RKC]

from the canon site
"Autofocusing does not operate if the effective maximum aperture is greater than f/5.6"
http://www.canon.co.uk/For_Home/Product_Finder/Cameras/EF_Lenses/Extenders/index.asp

think you will find you will need the sigma ones, but sure someone will be able to confirm it for you

ps suspect the sigma would be a fair bit cheaper, and Les has used the combo, so would think the way to go

 

[gembobs]

I am considering buying a 1.4 tc at some point in the next 12 months, and have been doing some reading around to figure out which way to go - so none of the below is from personal experience, only from what I have read.

* a 1.4x tc reduces your lens aperture by 1 stop (eg f4 lens becomes f5.6, f2.8 lens becomes f4 etc), a 2x tc reduces by 2 stops
* No lens / tc combo will autofocus on any canon body below a 1 series when maximum aperture is below f5.6 (will af on 1 series to f8 though)
* the canon tc's can only be used on certain canon lenses, mainly primes, but also the 70-200's - don't know if they work on third party lenses though - something to do with a recess on either the tc or lens, so it quite literally cannot be attached. (I think )
* third party tc's (Sigma, Kenko) can be used on any lens by any manufacturor (sp)


I hope that helps, and I believe this info is correct, if it isn't, I appologise, and I am sure someone who knows more will be able to chip in

 

[rickj]

give the kenko pro 300 dg a look these auto focus and good quality

 

[whitey]

the 1.4x doesnt give alot of reach IMO, still good though, one to look at on the sigma 70-200 could be a 2x, using one at the mo on my 70-200 (nikon fit on D300) with no problems, focus speed is still quick aswell

 

[evilian]

has anybody got any examle shots with one of these in use.
maybe a photo at 200mm and the same pic with the tele converter used.
thanks
ian