Tamron SP 28-80mm loose front

[guardian]

The front most portion of my Tamron SP 28-80mm seems a bit loose. It moves in and out perhaps a couple of mm. It also is free to move, it can be rocked, from side to side (what seems to me) too much.

Is there a way to tighten it up and restrain its freedom a bit? Or is this normal? Or is my lens just worn out?

[SkedAddled]

I have 2 copies of this lens, and both are precise, with no free play
in their mechanisms.

I dug out the copy that's less minty than the one I use, and found that
the rubber grip rings are easy to remove without damage.

Underneath the focus grip, there appears to be black tape
or perhaps a mylar/vinyl film. This thin film would appear
to be covering screws and/or other methods of adjustment,
or even attachment of the barrel elements to one another.
I did not remove the film, but may do so if it would help you
to realize a solution to your loose lens.

The other grip ring, over the zoom control, reveals screws.
I can only assume these are for fastening the zoom ring
to the inner zoom mechanism, as well as probably allowing
for some sort of center-axis alignment of the optics, judging
by the elongated holes and how the screwheads are positioned
within these holes. These screws are each bonded with some
sort of cement or glue, and are probably not meant to be
tampered with unless you have the equipment used during
the original manufacturing and alignment processes.



Having said all of the above, I would not recommend messing with
the mechanics of a zoom lens unless you have an extremely good
understanding of how they are assembled and adjusted, or you
happen to have some sort of repair manual available. I completely
messed up a 70-140 zoom lens by dismantling it for cleaning,
rendering it just about useless. As it was extremely cheap(US $,
I was not much concerned with how my adventure would turn out,
but I learned that I may never understand how zoom lenses
are properly assembled and adjusted.



After(again) having said all of the above and putting in my disclaimer,
I will offer my second SP 28-80 to you cheaply if you'd like to acquire one
in excellent mechanical, optical, and very good cosmetic condition.

[guardian]

Thank you, SkedAddled, for your very helpful reply to my post. I confess I only just now, admittedly days late, am seeing your response for the first time.

Sadly, you have confirmed my concern my new lens is not right. But receiving that confirmation is most helpful. This is one of only two Tamron Adaptall 2 SP lenses I own. I wish things had turned out better, but c'est la vie.

Regarding repair:

I did move the rubber grip aside and see the tape. I did not disturb the tape. I was cowed. I agree with you lens repair is enormously challenging . . at least it is for me. Yet, I'm somehow fascinated, at the same time, by the repair process. There is so much to learn.

After destroying my first repair project lens, a Zeiss Tessar f2.8, I was successful recently cleaning a Konica Hexanon 40mm f1.8. The latter is admittedly a very straightforward lens to dismantle. I also had a measure of success cleaning my Soligor 135mm f2.8. At least it is significantly cleaner and I did not destroy it. The internal fungus came right off.

Those experiences aside, I completely take your point that zoom lens repair is a special challenge, one requiring great knowledge and skill. And I don't have that kind of skill at this point. So I will hang on to my lens and "await developments" . . . . . I will wait to see if I become any smarter about lens repair. I have a Hexanon 52mm f1.8 coming in that needs repair. We shall see.

At least the Hexanon 52mm seller was open and honest about the lens he was selling. My Tamron SP 27A, OTOH, was sold without any disclosure at all of the loose front condition. And it's not the kind of problem that shows readily in a photo!!

[SkedAddled]

I apologize for only now seeing your reply, but I will reiterate my initial
warning about zoom lenses: They're complicated and difficult to figure out!

I also have a Soligor 135 f/2.8, in a T4 mount, and I disassembled it for
cleaning of obvious fungus. While the fungus seems to have been cleaned
very well, I probably did not take necessary precautions to ensure that
I could accurately reassemble the lens, which has resulted in a lens
which will not focus to infinity on my EOS cameras.
Of the three Soligor(Tokina-made) lenses I own, a 75-260 f/4.5,
a 400mm f/6.3, and a 135mm f/2.8, the 135 is the only lens I've received
which made me want to dismantle it for cleaning.

Knowing what I now know about these Tokina-made Soligor-branded lenses,
if I should(and probably will) acquire more, I am prepared to make infinity-focus
adjustments based on my previous experience, without dismantling the lenses.

As for your Tamron SP 28-80, I have found it to be an exceptional lens for
general-purpose use as a walkaround lens, so I might dig into the mechanics of it
with my less-minty copy, just to give you some satisfaction.
This would satisfy my own curiousity as well, and could make for an interesting
learning experience for the both of us.

[guardian]