Well, I pulled out my KM 28-75 for further study.
First, it doesn't have a window on it, so if that is a window, that's a big change. I'm thinking it's just markings and it's shinny there.
The part line on that lens looks about the same spot as the KM but they have shown the grip rubber near the end of the lens, not next to the part line like the KM.
On the KM, the front element/filter sticks past the side of the lens, it's the biggest part of the lens, pretty noticeable. That lens it's very noticably smaller than the barrel of the lens. So something has changed. Either they made the whole thing fatter, or the front is different. The lens shown does not have the inside ring on the front glass with the lens info. hat ring is 5mm wide if they took the lens from 67mm threads down to 62mm to standardize it, that's right where you would see it. As clearly KM wasn't worried about it before. This would also make the front stick inside the barrel OD a bit more as shown.
The KM version also has no switch. Something is down there. There is a visible change in shape.
I don't doubt it would be related, but I think it might be a heavy cosmetic job. Look at the sony 55-200 ("old one"), they changed the filter threads on that from the tamron to make it 55mm to be standardized. I think they did the same here.
I wouldn't put it past being a major revision of the tamron, maybe they got the optics, and gave it SSM (makes it fatter), and change the front ring size a bit.
They can do that and not hurt the ZA. The ZA has better range, probably better build, the Zeiss name. A lens like this just reduces demands for the ZA prices to come down, lets Sony let them remain high since with cheaper models around, no one can say there isn't options.
Sony needs a decent kit lens for A700, A900 this would do it. They may also be finding they just can't crank out ZA lens in large volumes, so they need to sell less of them. Look how long it's taking some of these to come to market. They very well are trying to shift demand while they get capacity up.
David Kilpatrick wrote:
PhotoTraveler wrote:I'm not so sure the 28-75 is the same lens. It's shaped different, looks slimmer, or it's longer (pick one). David is right the front glass looks similar, but everything else doesn't. It almost looks like the distance window is at the front of the lens. And it looks to have a switch on it down lower. Sony may have done some serious re-work, maybe SSM, maybe they changed the front filter ring to a common size.
It looks like the same 67mm to me, right down to the bayonet. Also, the front focus window is exactly where it should be if the Tamron/KM design is changed - same position of focus ring. And the focus lock is just the same addition compared to KM, the Tamron has it - different position, maybe. Overall it looks too much the Tamron not to be a revision of the lens (zoom barrel and focus placing, overall size, lock) - but that does not mean it is identical.
However, knowing Sony, I'll bet this proves to be a straight cosmetic/minor tweak variant of the Tamron selling for around £450 (where the CZ 24-70 is £1100+) to allow future Alpha 900 or 900v2, 900cheapie kits.