mfshadow wrote:
Sounds normal (and frustrating) to me. I've got the same lens for my
Nikon system and Canon system, the Nikon does have to be switched to
manual on the body as well.


No, it is not normal. Until 2 days ago, sliding the lens focusing ring
back allowed me to focus manually without moving the AF/MF switch on
the camera to "M". It did this by (as I explained in my first post)
disengaging the part that is driven by the screw in the camera body
from the focusing mechanism (ie you could focus but that thing did not
turn; you therefore do not have to switch the camera to "M" in order to
retract the screw).

If your lens did not allow this, it's broken.

Thanks for the reply.



wrote:
Hello,
I have a Tamron 90mm lens. This lens has a screw drive AF mechanism
(I'm talking about Nikon mount). To switch to MF, one can simply slide
the focus ring back, and the AF disengages; it's then possible to focus
manually without setting the camera to MF (which retracts the AF
screw).

The problem is the following: When I slide the MF ring back,
disengagament is not complete. I can focus, but sometimes the part that
mates to the screw also rotates (I can see this when the lens is not on
the camera). Obviously, this way I may damage the camera or lens if I
am not careful. Using AF, there is no problem; using MF is also
perfectly safe as long as I switch to MF from the camera too,
retracting the screw.

So, has anybody else had a similar problem with this (or another,
similar lens), did they get it fixed, and how much did it cost? I don't
really see a reason to fix it as it does not affect operation (except
in slowing me down a bit), but if it's cheap I may send it at some
point.

Thanks.