Teleconverters for Sigma Lenses (50-150 & 300 f4)

[dave_l.]

<p>I currently use a Nikon D90. My two telephoto lenses are a Sigma 50-150 f2.8 and a Sigma 300 f4 tele macro. The 50-150 is HSM focusing, the 300 is an older, screw driven focus model. <br>

I've been kicking around the idea of picking up a teleconverter to use with these, and ideally it would work with both of them, but primarily with the 300mm. But since the 300mm is discontinued, it's very hard to determine what might work. And no brand is particularly clear about which teleconverters autofocus with which system...pretty confusing. <br>

Any thoughts or guidance here? </p>

[don_cooper]

The sigma 1.4x should work fine with both lenses, although I,d worry about the quality with the 50-150. I used the

300 with the 1.4x for several years with excellent results until internal mould took over the 300.

[dave_l.]

<p>Could you specify which teleconverter model you used? The issue is that there have been so many generations of these converters that it's impossible to tell which versions will autofocus with which lenses. For example, I'm pretty sure that the most recent Sigma teleconverters will NOT autofocus with the 300mm, but that's only an educated guess.</p>

[don_cooper]

<p>You may be right Dave. I no longer have the converter that I used with the 300. I now have a newer one that I just tried it with the Sigma 300 and it does NOT focus. The newer one focuses with my Nikkor 300mm F4 AFS just fine. The markings on the one I have now are "APO TELE CONVERTER 1.4X EX". </p>

[dave_l.]

<p>After some more snooping, I think I'm stuck. It sounds like I can either get a newish Sigma brand teleconverter and get autofocus with my HSM lens (but not the screw-driven lens), or I can get an older Sigma/newer Kenko and get screw-driven autofocus (but not HSM). Oh well.</p>