Tamron 35-70 Zoom Front Name ring removal

[robbiechad]

Hi, I have a Tamron 35-70 Adaptall 2 Zoom lens, there is quite a bit of play in the focus mechanism, you can move the focus collar 2-3 millimetres, it looks to me like there are some loose screws or screw collar that has become loose in the top half of the lens, trouble is I cant get the name ring off which I think will allow me to tighten up any loose screws , is this name ring glued in or should it just unscrew? The lens does actually focus in either position and produces cracking pictures. I am just at a loss how to remove this name plate. Any help would be appreciated. Many thanks

[Ymmot]

Welcome to the forum.

Is it the Tamron adaptall 2 35-70 17A, which has constant 3.5 aperture?
if so check my old topic:
http://forum.mflenses.com/solving-focus-ring-play-in-tamron-17a-35-70-f-3-5-t51531.html
basically the screws you need are under the focussing rubber on this lens in this case, the name ring does not really remove on this lens, I think it probably is a (metalic) sticker anyways, no need to remove it on this lens.

O, and by all means do not remove the slotted ring at the back of the focus ring, that holds the helicoid together and is the focussing stop, dont mess with this, it can be very annoying to put back together correctly.

Dont know if it is the same for the 09A with varying 3.5-4.5 aperture. You could try the same with this lens and slide off the focussing rubber to check, the lenses seem to be related to some extend.

[robbiechad]

Hi Yammot, Thanks for the info, this lens is the 3.5 constant aperture model, 17A, I have had a look under the rubber sleeve at the three tiny grub screws, loosened them to release the sleeve but it doesnt come off there is something else that is holding it, it just moves back and forth, the grub screws lock the sleeve to the focus mechanism which is where the slop is, how does this sleeve come off, has it got an iternal cut out that allows it to slide off in one position only, I couldnt see any way of getting it off, tightening up the crews have no effect on the focus sleeve they just clamp the outer sleeve to the focus mechanism, and I think you are right the name ring doesnt come off it is solid!! I have put it back together and will await to see if anyone comes up with any suggestions, much appreciated anyway, thanks

[Ymmot]

Are you sure it is the entire focussing mechanism having play?
Do the front elements/group actually move/wobble along during the wobble in the focus ring, since I would not expect you to have cracking pictures then?

According to http://www.adaptall-2.org/lenses/17A.html there are three cosmetic versions, which might also differ slightly mechanically as far as I can see, since one version has at least a focussing helicoid that moves in the nikon direction as opposed to most other tamrons.
My lens is the second version, with normal tamron focussing direction and very finely diamond patterned grip.

I can give some more info on my exploits of fixing the wobble/play in mine.
In my case it was the outer sleeve of the focussing ring.
This could be seen since there was a small gap which varied in size with the play, located between the filtertread (attached to the focussing ring) and the name ring (attached to the front group/focussing assembly).

I first tried the name ring, but soon figured out that I could not remove it without damaging and it didnt wobble with the focus ring it so I left it.
Next I tried the tiny slotted ring at the back of the focus ring. I removed it and accidently untreaded the focussing helicoid, and found out the focussing ring was still wobbling and attached to the front group .
I then proceeded to put it back together asap to avoid dust so I didnt really investigate the insides further.
I then found the grub screws under the focussing rubber, moved and held the focussing ring/sleeve in the correct position and tightened them slightly (take care with this), and my lens was fixed.
So in case the front group does not wobble, I dont see what could be wrong besides the focussing ring (sleeve you called it I think?) being improperly attached to it.

I think you may be able to remove the entire focussing ring sleeve, by untreading the slotted ring on the back and loosening the grub screws under the rubber together, while taking care not to untread the helicoid.
Yet I dont really see what this would fix and there is a good potential to mess things up in this case.

Now if the grub screws do not do it, and the entire front group moves with the play as i mentioned at the start of the post, it may be something else.
It could be the cams-followers in the zooming mechanism, or the helicoid itself, both of which is again not something I would like to mess with.
If something is messed up with this, I would not expect the lens to perform cracking at all as the group placement/allignment may be off I would imagine?
That is almost almost impossible to fix without spares, mechanical diagrams / maintenance manual.
Naturally there could be more possibilities of something that could be wrong, yet I dont know what exactly as I do not have any repair manual or anything.
(see http://www.adaptall-2.org/articles/InsideZoomLens/InsideZoomLens.html, scroll down a bit to see an example of the cam-slots and followers)

As you can see I like to write longs stories,
I hope it helps you .
(btw, I am not a repairman, just someone who is mechanically inclined and does not have a issue with tinkering with a lens that I got for 5 euros)

[robbiechad]

Hi Yammot, Thanks for all the info, As far as I have been able to see, it seems the problem may lie with the zoom mechanism, from 35 to about 60 there is this movement in the focus sleeve, then when zoom to 70 the movement is gone , the lens focuses as it should with no play, once you start to zoom out to 35 again the movement returns. I actually can see a small piece of green roller which seems to have broken off somewhere so this must be part of one of the cam followers, which could indicate what the problem is, perhaps in a past life the lens has been dropped causeing the damage to the roller which in turn has led to the play in the mechanism. I took some pics with this lens at the weekend and will post a couple when I get the film developed later in the week. I have decided to leave well enough alone for the moment. Thanks for your input anyway it is much appreciated.