auto focus with the tamron 1.4

[bolling]

I have the canon 100-400L with the digital rebel and I have read that with the cheaper tamron 1.4 telecoverter I will still have autofocus. Is this true?

[CyberDyneSystems]

Maybe...

If the Tamron is designed to "lie" to the camera by not telling it that it is installed,. and thus not telling the camera that the effective aperture has been cut by another full stop... then "Maybe"

Maybe because there is no guarantee that the lens/camera combination will actually be able to function out of spec (ie: at smaller apertures than designed)

The DRebel is designed to AF with aperures of f/5.6 or larger. By installing a 1.4 T-con your aperture will be f/8... and thus the DRebel may simply not be able to AF.

It may work.. many have had good results with the type of T-con that "fools" the camera.. but often enough it just doesn't.

I would recomend that instead of the tamron el cheapo... you may want to consider the Canon and tape... this way you will have a better and you won't be running your $1,400.00 L lens through $79.00 Tamron glass. :wink:

[bolling]

Thanks for the reply, I have heard about the taping of the pins but do not know the procedure. What you say about not using the cheap glass makes sense. I you could explain the taping it would be appreciated.