Photoclubalpha

I'd be very interested. I'm into buying one of those two in several months to serve as an all-in-one backpacking lens. If the IQ would be better, I'd go with the 18-270. If it would be similar (or worse, of course) I'll go with the lighter 18-250. I understand that the 18-270 is shipping, but didn't find any comparison between the two.

The 18-270mm is not out in Sony Alpha mount yet as far I know. It may be shipping in Nikon and Canon though. It is going to be available in Alpha but like the 10-24mm, the other mounts have been scheduled first.

David

If and when the 18-270mm comes out in Sony mount I sort of doubt that it will have the VC mechanism. Probably no price reduction when they leave it out though.

I have a side question about this though. When Tamron VC lenses and Sigma OS lenses are released without VC/OS in Sony mount do they just remove the elements, fix them in place, or replace them with different elements? I suppose that the overall lens formula takes into account the VC/OS elements so you can't just remove them without changing the other lens elements too. Is that right?

I presume they just fix the elements centered. The Sigma lenses in non-OS version for Pentax and Sony cost exactly the same, and are exactly the same size, as the non-OS variants. Same will apply, we assume, Tamron. And it certainly will not appear in a VC version for Sony and Pentax!

David

There is a third lens to consider; the Sony 18-250

The Sony lens gains circular aperture blades as well as faster auto focusing over its Tamron twin. I think there were one or two other advantages that the Sony had over the Tamron, but I can't remember and can't find the article that compared them. If the Tamron 18-270 has better optics and wins against the Tamron 18-250, then there's still the little matter of comparing it to the Sony for those small (but important) mechanical differences.