Bitter Sweet!

[scoff]

Got my Christmas prezzie early - a 100-400L Canon and a 1.4X converter.
Looking on every compatability chart these go together no probs!
So I'm playing and nothing!! no auto focus! FFS I've got a duff lens, or TC?
So TC removed, lens works fine! Attach TC to 70-200L all is fine!
Ring place they came from and nope no Auto focus with this combination
So, do I keep the TC or get rid?
Slightly dissapointed at the mo...

 

[mho]

You will only get auto focus with that combination if you have a 1 series or eos 3.
The 1 series and eos 3 will auto focus with lens / combinations upto f8 all others are limited to 5.6.
You could always tape the 3 pins on the converter, to enable autofocus but it will be slow or not attain focus unless in very good light.

Keep the TC.

All you need to know about TC's HERE

Picture of taped pins HERE

 

[CT]

None 1 Series cameras.... 20D, 350D, 5D etc. only maintain autofocus as long as the new effective max aperture of the lens in use (with the converter) is f5.6 or larger.

1 Series cameras will still autofocus as long as the new max aperture isn't smaller than f8. The 100-400L will still AF fine with a converter on a 1 Series body

So nothing wrong with the converter at all, don't get rid, it's far too useful a bit of kit, and who knows what lenses or bodies you'll acquire in the future? :shrug:

 

[scoff]

Think I will keep the TC, I guess as long as I'm snapping static targets the MF will be ok, assuming my eyes are??

 

[CT]

You can always try the tape trick which Mark has linked to.

 

[scoff]

Cheers may give that a go, which pins am I taping? on the TC or lens?
Also the lens has an adjustment on for the zoom, to make it stiff or light, but when I use the focus ring the stiffness adjuster thing also moves.. this normal? can I do something to sort this?

 

[RobertP]

Cheers may give that a go, which pins am I taping? on the TC or lens?
Also the lens has an adjustment on for the zoom, to make it stiff or light, but when I use the focus ring the stiffness adjuster thing also moves.. this normal? can I do something to sort this?

Yes. That is normal. When you move it relative to the focus ring you adjust the friction - move the two together and it stays set.

I tend to use the friction control quite a lot normally. Loose if zooming a lot, tighter if just making smaller adjustments. I thought it would be a set it and forget it thing but I don't use it that way.

I have a cheapie tamron 1.4x which does not report its presence to the camera. My 20D focuses just as easily with the telecon as without - so if the taped pins works then go for it

As to where to tape I'd guess wherever is easiest as you are just breaking the circuit on those pin connections.