1.4/ 2x Converter buying advice

[RD400]

I borrowed a friends jessops 2x converter and been amazed the difference it has made to the len`s focal lenght now the question is would I see a great difference in between the jessop 2x at £80 or the below
Canon Canon EF 1.4x Converter £245
Canon Canon EF 2x Converter £280
Canon Extender EF 1.4x III £465
Canon Extender EF 2x III £439
Sigma 1.4x EX DG Tele Converter £199
Sigma 2x EX DG Tele Converter £235
Now the price`s of the other makes is a lot more than jessops what difference would I notice .
The lens below are what I`ll be using on my canon 550d
sigma 120-400 DG OS F4.5-5.6
sigma 10-20 DC F4-5.6
sigma 17-70 DC OS F2.8-4
cheers
mick

 

[heidfirst]

Sigma don't list the 10-20 & 17-70 as compatible with their TCs(but then again they aren't the sort of lenses that I would expect people to use a TC with).
On the 120-400 you lose AF.
http://www.sigma-photo.co.jp/english/support/faq/condaitr.htm#02

 

[Euan]

They may improve the focal length but with a significant loss to image quality. TC's are best kept to primes and fast zooms. You "may" get away with the 1.4 but the 2x's have a big impact. How did you find the image quality?

kenko also do 3rd party extenders which are supposed to be good also.

 

[FlyTVR]

I bought the Canon 2x III. Bolted it to a 70-200 F2.8L (Mk2) (a cracking lens).

Took it to Silverstone and Fairford. Used two 5Diis and a 7D. I am so dissapointed. I simply cannot get sharp images out of it. Tried IS off, IS mode 1, mode 2, on a monopod, off a monopod.

In the end I took it off and just shot with the lens on it's own.

I'm sending it back.

Of course this is just my experience and possibly I have a duff one - or I put it on wrong

Cheers.

Dav

 

[the ghost]

hmmm my mkII works fine on my 100-400 just focus a big tad slow

 

[Tugster]

I bought the Canon 2x III. Bolted it to a 70-200 F2.8L (Mk2) (a cracking lens).

Took it to Silverstone and Fairford. Used two 5Diis and a 7D. I am so dissapointed. I simply cannot get sharp images out of it. Tried IS off, IS mode 1, mode 2, on a monopod, off a monopod.

In the end I took it off and just shot with the lens on it's own.

I'm sending it back.

Of course this is just my experience and possibly I have a duff one - or I put it on wrong

Cheers.

Dav

Dav....Sorry to hear about the 2x....Are you looking for a replacement or a refund ? Can you keep the thread updated on your findings...thanks