Noise? Who's making noise?
Joe, there is no "supposedly" about it. If you disassemble the SONY 18-250 lens, it has components 95% identical to the TAMRON 18-250. Does that sound like some kind of "accidental" copy? How far does "supposed" go these days? As far as a noise comparison, I suppose you would have to do a side-by-side to reveal that, because you will find, as I recently did, that identical lenses make different amounts of noises. Just depends on who and when they were constructed.
Originally Posted by joenmell
As far as I have determined, the TAMRON 18-250, having a six-year warranty and outstanding results for this kind of lens, would be my pick, every time, especially concerning the SONY-mount.
Originally Posted by joenmell
If it were Canon or Nikon, the choice would be the TAMRON 18-270 VC lens, to get some stability to those two brands.
There has be a good deal of review for the super-zoom. Stay away from 18-200s, 28-200s, and the 28-300s. The 18-250 (270) is a much more refined generation lens. I have owned them all (TAMRON) ... and that's my nickel's worth. ;)
Good luck with your new TAMRON lens.
SIGMA's version of the 18-250
Joe, I'll be honest, here ... I have kind of gotten away from testing this level of lens and most of the "APS-C only" lenses. In fact, my most recent APS-C only lens purchase was the unique Samyang MF 8mm Fisheye, which delivers a really nice, but effective affordable result. Currently, I need lenses that I can directly swap between the α850 and α700 and most of the exclusive ones (except for the T17-50mm and S10-20mm) have been sold, to reduce weight. I am going to have to leave it to YOU and others to answer the call for any 'new" APS-C lens input and step back. I sold my TAMRON 18-250 with the α100, about a year ago. It was a terrific lens on that camera.
There are only a few known SONY users in the area and I am pretty positive no one had the SIGMA-version of the lens for discussion. My "solution suggestion" for you would be to purchase both the TAMRON and the SIGMA from a common source (perhaps B&H) and then return "the one" that does not do well or lacks what you need.
Yes, you may be out a few hundred dollars for the test, on your credit card (you will eventually get your refund), but you should have your answer. Often, it is relatively impossible to have both lenses available to you in a store (especially in the SONY-mount) and you have to resort to such "directly mailed" examination.
The fact of the matter is that you seem quite serious about your choice and having YOU personally conduct your own examination seems totally fair. Let's face it, without a solid side-by-side test published, that you can refer to, the yoke of responsibility is yours, this time.
Personally, I have spent many hours pouring over lens' results and trying to focus in on the most "bang for the buck," just like you are now. Any "hero" can buy top drawer glass and probably get the result they seek with it. I understand "bang for the budget," too. If you do come across a direct comparison without having to resort to doing this yourself, please add a link to this thread so that the silent group of others may benefit from your research, saving the rest time and money in these kind of comparisons.
The biggest avantage I can see about the SIGMA is that is has OS - "Optical Stabilization" for the Canon and Nikon mounts, which TAMRON has in it 18-270mm VC version. I'd save the money with the "vanilla"-version on the SONY DSLR.
BTW: You may try and ask on the Dyxum site, and see if some of our overseas friends have had this lens to comment on. They seem to be big on SIGMA alternatives. Simply join the board, review the past few months of "Lenses" forum postings, to see if someone has asked about this comparison, and if you do not find your answer, then pose your question in their forum and see what falls out.
Good luck with this and I apologize for not having a more direct answer on it. I look forward to hearing some results in your hunt.