Anyone using 1.4x on the 100-400L? Can you share info?

[Adam Hicks]

Info on B&H's site about the 1.4x on the 100-400 is kinda sketchy, so could someone provide the f numbers at 100 and 400, as well as the AF implications of using the TC? Does it require use of the center point for AF or do all points still work? Anything to consider before I order one?

Thanks!
Adam

[Scottes]

All of your answer are here: http://photography-on-the.net/forum/showthread.php?t=41922

[Adam Hicks]

Actually it just confused me more... it states that:

"autofocus is possible on any EOS camera when combined with a lens having an f/4 or faster maximum aperture."

Then it says:

"B: All other EOS bodies (besides the 1 series) require f/5.6 to AF
Models include D30, D60, 10D, 300D, and 20D"

and THEN it says that the 10D does not support AF with the 100-400 using the 1.4x or the 2.0x. The 100-400 is a f4.5 max aperture, so it fits the second statement (larger than 5.6) but not the first.

On top of that nothing is mentioned about the 20D and whether or not the TC requirements have changed from the 10D.

That's my dillema :?

Adam

[CyberDyneSystems]

Well..

You do answer all your own questions with the very info you are confused about. :)

The first statement is a quote from Canon's site refering to the 1.4X T-con. It says...

"autofocus is possible on any EOS camera when combined with a lens having an f/4 or faster maximum aperture."

Again.. it says this about the 1.4X T-con.

So.. can you draw a conclusion from that? The 100-400 does not open up to f/4... so.. it does not qualify. :(

As for the 20D.. the "Sticky" states that ALL Eos cameras need at least f/5.6 to auto focus EXCEPT the 1 Series and the EOS 3. This has not changed with the 20D..

So the answer is.. for both reasons above... nope :(

[PacAce]

"autofocus is possible on any EOS camera when combined with a lens having an f/4 or faster maximum aperture."


The 100-400 does not fall in this category so you can scratch this line.


"B: All other EOS bodies (besides the 1 series) require f/5.6 to AF
Models include D30, D60, 10D, 300D, and 20D"


The 100-400 does fall in this category so you can AF with the 20D. However this is without the 1.4x TC.


and THEN it says that the 10D does not support AF with the 100-400 using the 1.4x or the 2.0x. The 100-400 is a f4.5 max aperture, so it fits the second statement (larger than 5.6) but not the first.


The 100-400 with the 1.4x becomes a 140-560 f/8 zoom and, hence, will not AF with the 20D in this combo.

[Scottes]

The 20D requires f/5.6 or larger aperture to AF, same as the 10D.

The 100-400 L at 100mm is max aperture of f/4.5, and at 400mm it's max aperture is f/5.6.

A 1.4 TC adds one stop, bringing this to f/6.3 and f/8 respectively.

So the 100-400 L with a 1.4 TC will not AF on the 20D, at any range of the lens's zoom.

[CyberDyneSystems]

Bwahhahahaha

Triple post! :mrgreen:

Too funny!

[Adam Hicks]

Wellllll.... crap.

So does that mean the Bigma 50-500 cannot AF at it's long range? Isn't it an f6.3?

[CyberDyneSystems]

Technically.. it would not be able to...

It gets away with it though.. because it lies.

And yes.. you can try a 1.4X t-con and teach it to lie too...

It's called the "tape trick".

The trouble with this is there really is a cut off point for where AF will become unreliable on the camera. using the tape trick can cause bad focus AND can have bad effects on the focus motor .. like burning it out alltogether.

[Lamium]

the tape trick has never worked with my 100-400 and the 1.4X. The af-motor just keeps on hunting and hunting and hunting ...

[Roy NN7DX]

100-400L/IS with tape used with Kenko Pro Series 1.4x:

Works well with 300D... Slightly better image than 140% upsample in PS.

Does not AF with 10D... Sent 10D to Canon with complaint about AF sensitivity... Returned "aligned" still no AF using tape and 1.4x

Works with 20D but image is better using 140% upsample in PS than when using 1.4X...

I'd hoped the 1.4x would do better using the 100-400L/IS and the 20D but it hits the limit of the lens with the added resolution of the camera...

This all may be unique to my gear... Someone else might have better "luck" with the 10D or enhanced images using the TC with their 20D...

[Adam Hicks]

Thanks for sharing your experience! Guess I'll have to pick up that 400mm f2.8 prime and use the TC on it ;)

Shyaa right.

[CyberDyneSystems]

100-400L/IS with tape used with Kenko Pro Series 1.4x:

Works well with 300D... Slightly better image than 140% upsample in PS.

Does not AF with 10D... Sent 10D to Canon with complaint about AF sensitivity... Returned "aligned" still no AF using tape and 1.4x

Works with 20D but image is better using 140% upsample in PS than when using 1.4X...

I'd hoped the 1.4x would do better using the 100-400L/IS and the 20D but it hits the limit of the lens with the added resolution of the camera...

This all may be unique to my gear... Someone else might have better "luck" with the 10D or enhanced images using the TC with their 20D...

Indeed,, the results are camera specific.. that it will work with your 300D does not in any way mean t will work with another.

Again.. by trying the tape trick, you are asking the camera to function out of spec. With all things like this,. results may vary dramatically. From working fine,.. or causing actual damage.

Try this at your own risk.