70-300L AF IS goes *CLUNK!* (??)

[RustyTheGeek]

Some of you may remember my little poll a while back asking what to replace my 70-300 IS EF lens with after a barter trade with a buddy. Well, I finally did the deal and I decided to get the 70-300L. So now I have a nice Thinkpad X301 all tricked out (from the trade) and a new 70-300L.

What's interesting is this...

- Slap that 70-300L on the 5D3 and point it all over the place, AF performance is fast and smooth, fairly quiet and nice.
- Add a Tamron 1.4x TC (140F-CA) and the AF slows a bit. Not unexpected. Still works pretty good. HOWEVER...

... when the TC is attached, the IS tends to JUMP from time to time and makes a CLUNK NOISE. You can feel the clunk too. It still autofocuses on the target but the IS going CLUNK is weird. I haven't been able to detect a clunk or jump when the TC isn't connected. Anyone have some thoughts?

I've had the Tamron TC for quite a while and from what I have read around this forum, the Kenko 1.4X DGX is (I guess) the ideal TC but I don't necc want to buy another TC. Anyone have a Tamron 1.4X TC like mine and like it just as much? Curious how they compare.

 

[Marsu42]

Good luck finding anyone with the Tamron tc combination, I just can say that the 70-300L+Kenko 1.4x tc combination never goes *clunk!* on the 60d - in contrast to the very noisy 100L hybrid IS where a very frightening *eeek!* sound is common when pointing the lens down or up :-o

 

[RS2021]

70-300L is a quality Canon zoom with a growing reputation...get it off the Tamron TC....particularly if we are talking jumping and noises.

 

[RustyTheGeek]

Yeah. I started this thread for two reasons...

- Get opinions/reactions from others with regard to the anomaly
- Inform others in case this truly is a possible hazard to the lens

I don't see how a TC could cause damage (or change the AF mechanism) but I guess you never know. I'm glad to hear someone has used the Kenko successfully. I'll consider obtaining that one perhaps after I see some more posts.

I've never had a problem with this TC before on any other lens I've used it with.

 

[wickidwombat]

it could be the 5D3 and the tamron
I know the Kenko 1.4 and the 5D3 are a bit wierd for example if i stack the kenko 1.4 on the canon 2x and the 70-200 f2.8 II then its fine on the 5Dmk2 but on the 5Dmk3 the aperture flicks wildly between f5.6 and f8

 

[RustyTheGeek]

it could be the 5D3 and the tamron
I know the Kenko 1.4 and the 5D3 are a bit wierd for example if i stack the kenko 1.4 on the canon 2x and the 70-200 f2.8 II then its fine on the 5Dmk2 but on the 5Dmk3 the aperture flicks wildly between f5.6 and f8

Well, FYI - no problems at all with the Tamron 1.4x I have on the 5D3 + 70-200/2.8IS-v1.

 

[wickidwombat]

it could be the 5D3 and the tamron
I know the Kenko 1.4 and the 5D3 are a bit wierd for example if i stack the kenko 1.4 on the canon 2x and the 70-200 f2.8 II then its fine on the 5Dmk2 but on the 5Dmk3 the aperture flicks wildly between f5.6 and f8

Well, FYI - no problems at all with the Tamron 1.4x I have on the 5D3 + 70-200/2.8IS-v1.

mine is fine with just the 1.4 its only when i stack the 2x mk canon TC that it goes all screwy

 

[RustyTheGeek]

FYI UPDATE - 70-300 IS L w/ Kenko 1.4X PRO 300 Teleconverter DGX
http://www.amazon.com/gp/product/B002C6QC3E/ref=oh_details_o04_s00_i00?ie=UTF8&psc=1

I got the new Kenko TC above. IS seems to work great, no "CLUNK!" when stabilizing using the Kenko TC.

END FYI UPDATE.