Tamron SP 70-300 VC Di USD + 1.4 Teleconverter?

I'm contemplating the purchase of a teleconverter.How many of you have used a 1.4 TC with your Tamron SP 70-300 VC Di USD? What TC do you use? Could you show me some samples of IQ and share your experiences? I called tamron today and they told me this lens isn't really made for tc's but the only thing she told me about was the loss of AF and an F-stop (which I already knew about).

I recall seeing a thread on this on dbreview recently? I believe some folks were having luck with the Kenko 1.4. I also own this lens and am interested in this potential.

I've tried using it with the TC and because the Kenko DG TC with this lens doesn't report properly to the camera the AF still worked. From what I've heard / seen DGX version of the TC reports properly and the AF doesn't work. I don't have any samples to share at the moment, but I recall IQ being quite good @ 420mm.

DiMAn0684 wrote in post #12489689
I've tried using it with the TC and because the Kenko DG TC with this lens doesn't report properly to the camera the AF still worked. From what I've heard / seen DGX version of the TC reports properly and the AF doesn't work. I don't have any samples to share at the moment, but I recall IQ being quite good @ 420mm.

So I should try the DGX or the DG? I'm confused. I almost always shoot manual focus anyways so that won't be an issue.

Will you please upload any sample photos?

The Kenko 1.4 Pro300 DGX preserves AF on this lens (and probably any other), regardless of the DSLR you are using. I have used it with the Tamron lens you are asking about. It requires A LOT of light. Without it, it hunts like mad. Since the lens has full-time manual focus, you can get it into approximate focus and then the lens often will take over and achieve focus for you.

I know you asked about quality. From my experience using the DGX with the Canon 400 5.6, I'd say it doesn't hurt IQ much. The biggest concern is trying to focus and get a good steady image with all that magnification, even using a tripod. No surprise there.

I think I have some images taken with the Tamron and TC. I'll look and see...

Edit: I found a few, but I don't really think they are a good indicator of how well the TC performs with the lens. They were taken right after I got the lens and TC. Sorry, maybe later...

ShaneKPhotography wrote in post #12489501
I'm contemplating the purchase of a teleconverter.How many of you have used a 1.4 TC with your Tamron SP 70-300 VC Di USD? What TC do you use? Could you show me some samples of IQ and share your experiences? I called tamron today and they told me this lens isn't really made for tc's but the only thing she told me about was the loss of AF and an F-stop (which I already knew about).

i'm not sure it would be worth it, poor AF at best, gonna be super slow if you stop it down a ways for better sharpness

definitely can't use canon tc with it since they wont fit (and thus i haven't tried it myself)

With kenko 2x DG.

It works, but the quality is not great. Autofocus works at the shorter end but not at the longer end. Overall, I think you'd get better results from cropping.

This is a resized and sharpened photo, not a crop.