1.4TC for Sigma 500mm f/4.5 (AF)

Is anyone aware of a 1.4 TC that will maintain AF with the Sigma 500mm f/4.5 on a 1DM2 ? The Canon 1.4 will not in spite of the combined aperture being less then f/8.
I can use the Canon 1.4 on my Canon 400 f/5.6 with no problem.

Hey Scott,

I used a Tamron 2x on my one last weekend... with AF on the 1D MkII. The Tamrons don't appear to report back the aperture change to the camera. You might want to give the Tamron 1.4x a look...

Cadwell, Thanks for responding.
1. Are you saying that the Tamron was able to maintain AF with the 1DM2?
2. How do you set the lens aperture if the TC doesn't report the aperture back to the camera?
3. Is that the Tamron or Tamron SP?

I can answer number 2....

2. What the number displayed in the viewinder and exif says regarding aperture in this case is unimprtant. When a TC is added, asyou know,.. no "stopping down" is occuring in the lens optics.. but a loss of light is occuring do to change in focal length and and extra glass... the resulting change in f/stop is going to be metered correctly via TTL no matter what "f/number" the camera "reports" to you.

The Canon and Sigma TC's "tell" the camera it is loosing the light electronically.. thus the correct number on the exif.. the "off brand" TCs do not.. but the TTl metering will still give you the right exposure either way.

Your Camera will just tell you what f/stop you lens is set to as if the T-Con weren't there. You still get correct exposure.

As for question's one and three... I personally don't have anything definitive yet,. but there is also some new info in the "T-con sticky" recently added that is specific to the Tamron and Tokina "off brand" T-cs that may be of help.

I have been seriously considering getting some of these TCs just so I can do my own testing and add the info to the Sticky...

Be sure and let us know what you come up wiht in your tests!

1. Yes. It was better on the centre focus point than the others, but then that is to be expected.

2. As CDS said.

3. Not sure to be honest, it wasn't my TC - it belonged to Andy (despot). I just tried it out of interest. I'm expecting to try a 1.4x Tamron on the lens soon.

Thanks.

I've been looking for the same thing on my 20D, but I need an extender that will not report back the true lens aperture since in my case the 20D won't AF above f/5.6. Even then it might hunt a lot being about 1/3rd stop above f/5.6. I think the choices there are the Kenko or older, black Tamrons.

Bob Atkins says the older, black Tamrons do not AF as well as the Canons and hunt a lot, and have vignetting problems on the longer primes (listing the 500/4.5 there).

Here's the review:
http://www.bobatkins.c​om/photography/reviews​/tcs.html

CDS said the 1.4x used to work with his 500/4.5 and 1D Mk II, but then stopped working. Do you want to try the Sigma 1.4x to see if it works for you? I'm not far from you so we could meet up somewhere with our TCs and 500/4.5's. A mini 500/4.5 and TC convention.

pcasciola wrote:
CDS said the 1.4x used to work with his 500/4.5 and 1D Mk II, but then stopped working. Do you want to try the Sigma 1.4x to see if it works for you? I'm not far from you so we could meet up somewhere with our TCs and 500/4.5's. A mini 500/4.5 and TC convention.

The Sigma 1.4EX TC does not AF with this lens on a 1D Mk II. I know I've tried it. Also, I've talked to Sigma US, UK and Japan about it and they all say it "won't work". They can't give me a rational explanation as to why, but it won't.

I believe you, but I'm confused.

Have a read here. CDS said this combination used to work, and Scott says the Canon 1.4x works fine too, but then CDS tried the Canon 1.4x and it didn't work:
https://photography-on-the.net/forum/showthre​ad.php?t=39461

pcasciola wrote:
I believe you, but I'm confused.

Have a read here. CDS said this combination used to work, and Scott says the Canon 1.4x works fine too, but then CDS tried the Canon 1.4x and it didn't work:
https://photography-on-the.net/forum/showthre​ad.php?t=39461

CDS reckons it used to work with his Mark I not his Mark II. When I bought the 500mm it wouldn't work for me and Scott tried it with his TC and Mark II as a test for me and it didn't work for him either, hence Scott asking the question now...

What you're missing from this discussion, Phil, is the series of PM conversations Scott, CDS and I had a few weeks ago on this subject

Cadwell wrote:
What you're missing from this discussion, Phil, is the series of PM conversations Scott, CDS and I had a few weeks ago on this subject

LOL. Can I be CC'd in those now?

Thanks for clearing this up, because that other thread left me really confused.

pcasciola wrote:
I believe you, but I'm confused.

Have a read here. CDS said this combination used to work, and Scott says the Canon 1.4x works fine too, but then CDS tried the Canon 1.4x and it didn't work:
https://photography-on-the.net/forum/showthre​ad.php?t=39461

Phil the link above does not tell the whole story...
at the time the above thread was posted I was confused.. my memory had failed me..

The Sigma 500mm DID AF with the SIgma (and Canon ) 1.4X TC on my old 1D ("classic" 4.5MP)

for some reason I never use TCs much with the lens so it was months before I "discovered" it would not AF on the MkII...

At that point I recalled it had autofocused with the 1.4X in the past so I was dumbfounded and spent a few weeks tweeking the MkII custom functions.. trying to get the AF back. (and posted the above thread)

Finally I realised it was never the MkII I recalled the AF with the T-C.. (at least untill today this is what I felt was true) ...it was on the older 1D 4.5MP camera long since sold off....

FYI I have also tried the MkII and Sigma combo with the Canon 1.4X and no joy there either.


But now it clearly gets "weirder" as ScottBErger thought his combo did AF in that old thread...

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If anything I am now even more confused

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1. The Canon 1.4 and 1DM2 will not AF with the Sigma 500 f/4.5. If I suggested it did in the past, I must have been mixing up the Sigma 500 f/4.5 and the Canon 400 f/5.6 which does AF.
2. I have read numerous posts at Photo.net and gotten PM's from Cadwell that the Tamron 1.4x will AF with the 1DM2 and Sigma 500 f/4.5. It is available at B&H: http://www.bhphotovide​o.com …tails&Q=&sku=53​109&is=REG
3. I don't know if the SP version will AF.
4. The article by Bob Atkins isn't as negative as suggested.
"Both the 1.4x and 2x TCs show some image vignetting with long telephoto primes like the 300/2.8, 500/4.5 and 600/4. Center sharpness is comparable to the Canon TCs, but edge/corner sharpness is lower. Note that on small sensor (APS-C) digital SLRs like the Digital Rebel and EOS 20D, vignetting will not be a problem and edge quality will not be as large an issue. The Tamron TCs are significantly cheaper than the Canon TCs, so they can be good value"
I always leave enough room to crop.
If anyone knows if the Tamron 1.4X SP will work, let us know!

Here is the e mail I sent to Sigma:
Dear Sir/Madam,

Can you please explain why the Sigma 500mm f/4.5 EX APO HSM does not maintain the ability to autofocus on a Canon 1DM2 when used with a Canon 1.4 tele extender. This is reported by numerous users and is very frustrating.

Are you working on a solution? This is a fantastic lens, but it's inability to maintain AF with a TC is a major drawback.

Thanks,

Scott Berger

And here is their moronic response:

"Thank you for your inquiry.

This lens and teleconverter only work in Manual focus mode.



Sigma Corp. of America

15 Fleetwood Court

Ronkonkoma, NY 11779

1-800-896-6858

1-631-585-1144

info@sigmaphoto.com"
Really helpful, Huh!