28-70 f2,8 with 1,4X or 2X extenders?possible?

[angelo_smaldo]

someone know if extenders 2x or 1,4 x work on a zoom 28-70 f2,8

(sigma )with my eos 1?or is impossible to use for problem to attach

the two elements?

i know canon extenders work only on L lenses...

 

which company product extenders for sigma 28-70?tamron?kenko?sigma?

or??

 

OF course i want buy couse in future i ll need an extenders couse i

m looking for a good tele for a my canon(400mm)i want to know if I

can use on 28-70 zoom only in exeptional contingency....

 

 

if work....other then loss of 2 stops...the results are accetable?

 

thanx

[linden_l]

I don't think so, not with Canon's short tele zooms. Not sure if third parties make any of them...

[don_baccus]

The Canon 1.4x and 2x will not physically mate with the 28-70/2.8 so their use is not possible. The extenders only mount on lenses with a recessed rear element, and the 28-70/2.8 has a flush rear element.

 

Tamron's extender (the original one, at least, I'm not familiar with the SP) should mount fine on lenses with a flush rear element though I don't own the extender myself so can't guarantee it.

[scott_ferris]

Hi Angelo,

 

I have used the 24-70 f 2.8L with a Canon 2x Mk II but you need

to use a 12 extension tube between them and you lose focus to

infinity. I was using it for macro work and would not recommend

the combo.

 

Take care, Scott.

[jbq]

Extenders are usually not recommended with zooms.

 

Canon's extenders don't work on short lenses, they require certain telephoto zooms or long primes (currently L telephoto zooms and L primes longer than 135mm, if I remember correctly).