sony vs tamron 18-250

[Dr. Harout]

You could laugh, but use a small toothbrush.

[alphaPDX]

I've recently gone with the Tamron; does fine work indeed (see http://www.picasaweb.google.com/alphaPDX/MegaTamron for sampler). Sharp when I want it to be, smooth when I don't, nice color and decently light.

I have noticed (with a bit of dismay) that when focusing manually the drive screw seems to stay in the lens socket - I need to torque harder with this lens to focus, and I feel the gears turning. When it's off the camera it moves easily and pretty quietly. Does the Sony copy feel the same? And do the thousands of other copies of this lens feel that way? It was quite a surprise to feel the resistance, a bit spooky.

[stevecim]

Hi AlphaPDX

On my old Sigma 170-500 the drive screw remained in the lens socket on my A350 (did not on any of my film bodys), does not happen on my new Tamron 70-300 LD Di

Cheers, Stephen

[Al_]

I've recently gone with the Tamron; does fine work indeed (see http://www.picasaweb.google.com/alphaPDX/MegaTamron for sampler). Sharp when I want it to be, smooth when I don't, nice color and decently light.

I have noticed (with a bit of dismay) that when focusing manually the drive screw seems to stay in the lens socket - I need to torque harder with this lens to focus, and I feel the gears turning. When it's off the camera it moves easily and pretty quietly. Does the Sony copy feel the same? And do the thousands of other copies of this lens feel that way? It was quite a surprise to feel the resistance, a bit spooky.

This happens to me too. Actually, it seems to happen with all of my lenses on either the A200 or A700. Only that the focus ring on the Tamron 18-250 is a little bit stiffer than the others to begin with. Try this. With the camera turned on and without a lens mounted, switch the AF/MF switch back and forth and observe the slotted screw. You'll notice that it doesn't retract. So when you are using manual focus, the slotted screw stays in the lens, giving more resistance than if you turned the focus ring with the lens off the camera.

[alphaPDX]

It feels 'wrong' to me because none of my lenses have done this before, so I feel like I'm stressing the screw unnecessarily. Two Tamrons (the 17-35 and 28-200) and three Minoltae (50, 35-105N, 75-300N) felt smooth and free in MF mode.
Does anyone know if the 17-50 does this too? Maybe it's a Di-II 'feature' since the others were merely Di.. ?