Question about canon 2x TC

[Kev M]

One of the blokes at the camera club last night was thinking of getting a 2x TC to replace his 1.4 but had heard somewhere that it wouldn't work with his 100-400 IS lens. Does anybody know whether that's true or not? If it makes any difference he's got a 1D body.

Ta very much like.
Kev

 

[EOS_JD]

With a 1d, it allows AF at appertures of f8 and larger so with the 100-400 having a maximum apperture of f4.5-5.6, losing one stop would not take the smallest apperture above f8. It would become a 140-560 f6.3-8 (I think).

Because you lose 2 stops of light this would make the max apperture f11 - so he'll lose AF.

f11 is a VERY slow apperture for such a long lens.

JD

 

[mho]

and the results are not very good with the 2x on the 100-400, much much better on other lens's.

 

[Kev M]

Ta very much I'll pass the info on next week.