Is the 2x III extender prone to decentering?

Hi,

So I first bought a refurbished 2x iii, and if I remember correctly it was soft on the left side. So, then I just received a brand new 2x iii and now the bottom half is soft--and not just the edge, basically the whole bottom half.

I find it weird that two copies in a row are bad. Is this a known issue with this extender?

Note--I did check if it was my bare lens (I tested with my 70-200) quite a few times and it appears not to be the problem. I also have a 1.4 iii extender that I tried the same lens and test with and it's fine. So, I would say it's probably not the test lens.

Guess I'm gonna have to try a 3rd. Sigh.

Xyclopx wrote in post #17018182
Hi,

So I first bought a refurbished 2x iii, and if I remember correctly it was soft on the left side. So, then I just received a brand new 2x iii and now the bottom half is soft--and not just the edge, basically the whole bottom half.

I find it weird that two copies in a row are bad. Is this a known issue with this extender?

Note--I did check if it was my bare lens (I tested with my 70-200) quite a few times and it appears not to be the problem. I also have a 1.4 iii extender that I tried the same lens and test with and it's fine. So, I would say it's probably not the test lens.

Guess I'm gonna have to try a 3rd. Sigh.

I have it and it's great. Virtually no loss of image quality when using the 2X extender.

I have used two and never experienced this. The extenders will exaggerate any flaw with the actual lens it is being used on, so it makes me wonder if your 70-200 II is decentered (which I have had...) and is making it far more obvious when the 2x is being used.

Something to check out.

Invertalon wrote in post #17018339
I have used two and never experienced this. The extenders will exaggerate any flaw with the actual lens it is being used on, so it makes me wonder if your 70-200 II is decentered (which I have had...) and is making it far more obvious when the 2x is being used.

Something to check out.

That was my thought. But as I said I checked this over and over many times. The lens is flawless. And also each extender was decentered in a different direction. If each one showed the same flaw consistently then that would lend itself to your hypothesis.

True... That is a new one that I have not heard before!