Tokina ATX 80-200mm F2.8 SD focus problems

mavtop · Joined: 10 Apr 2016 Posts: 32

i was thinking about them, but those are not holes, are like pins, they are higher of the base.

Is it normal ? This is my first disassembly, maybe i'm wrong.

thanks anyway
mav_top

mavtop · Joined: 10 Apr 2016 Posts: 32

Yes, thanks cooltouch,

i used the spanner wrench and i successed to remove that len too.

#Second len out

I will go on

mav_top

mavtop · Joined: 10 Apr 2016 Posts: 32

and also the 3th len is out, this is the column Smile

# third len

and i got access to the 2nd block

# third len and 2nd block

mavtop · Joined: 10 Apr 2016 Posts: 32

i can't open the second block, Nelson did it easily, unscrewing it with the hands, but i can't, neither using the spanner wrench tool.

Anyway i think the problem is on the rear element, infact if i shake the body of the len without all the 4 lens removed it hear some movement.

The problem is that i can't remove the mount.

It has a tiny screw and i can easily remove it, more 3 larger screw, but i haven't a star screwdriver for them.

I will have to look later at the rear element.

Nelson didn't post a video about it.

Now i will clean all the mirrors i removed and recompose the front part.

If someone has some ideas for the rear element.

mav_top

mavtop · Joined: 10 Apr 2016 Posts: 32

I'm thinking that it could be an infinity focus problem, easily viewable at 80mm, but not at mid and long focal length (at 200mm).

I found an old post about Lloydy http://forum.mflenses.com/tokina-at-x-80-200-2-8-infinty-focus-problem-t57126,highlight,+tokina.html

and he too had same problem like mine, infinity focus at 80mm.

I found 3 screws under the tripod collar,

I have to know if i need to remove the rear mount to adjust it, or i can directly remove those 3 screws (under the tripod collar) and try with them.

I read somewhere that infinity focus can be adjusted from there (for the ATX 100-300 for example), so if someone has some clue about it.

This is the post about the Tokina AT-X 100-300 F4

http://forum.mflenses.com/tokina-100-300mm-f4-adjust-focusing-t49961,highlight,+tokina.html

I have 3 screws like those showed in that post, more on another site

http://www.kyphoto.com/classics/variouslenses.html

for focusing problem loose the screw under the tripod collar and adjust infinity focus then lock them.

In another forum, someone tell to loose the 3 screws on the front group and then move the focus up to infinity focus is perfect then lock the screws.

This is the link

http://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/318919-help-fixing-infinity-focus-tokina-x-80-200-2-8-ka.html

So which of 3 screws i have to loose, the front or under the tripod collar ?

Thanks everyone for the help
mav_top

WNG555 · Joined: 18 Dec 2014 Posts: 784 Location: Arrid-Zone-A, USA

I don't have info regarding the infinity focus adjustment. Usually, it's a focus ring stop block that's screwed in place. Miine doesn't have infinity issue.
As for the inner lens assembly, mine unscrewed rather easily. But if yours doesn't it is likely due to thread locker. You need acetone, with a cotton swab, soak into the threads for a minute. Then the thread locker releases.

The rear mount came off mine rather straight forward. I had an Olympus OM mount. You may need an X drive/posidrive screwdriver. The screws are not Philips, which have a different profile and can strip the heads if they are tight.
The rear element assembly unscrews like the front one.

cooltouch · Joined: 15 Jan 2009 Posts: 9096 Location: Houston, Texas

On cameras and lenses, any screws with "x" shaped head slots are definitely not Phillips. My old camera repair instructor called them "cross points."' The profiles are entirely different -- Phillips are more pointy shaped. Fortunately the screwdrivers you most often find in these small jewelers screwdriver sets are cross points. But I should point out that if a screw is in really tight, it is still possible to strip its head with a cross point. So care must always be exercised.

mavtop · Joined: 10 Apr 2016 Posts: 32

Thanks for the answers, after remounting all, i tried to focus to infinity, no way at 80-100-200mm too.

I have infinity focus problem. I can easily focus object at 0,5-2-3 meters then no more.

When i have more time i will try to loosen the 3 screw on the front element.

This is that i found for the Tokina 80-200mm F4:

So, to adjust lenses for infinity focus, set zoom ring on infinity position and just loosen those three screws (just loosen, a one turn is enough) to discard tube contact with focusing helicoid. When screws are loose, return zoom ring to a bit closer than infinity mark (notice that you won't move focusing helicoid now because there's no contact with tube), and then fasten just one screw, attach lenses to a camera and try to get distant object into focus by turning focusing ring. If focus is still not achieved, repeat the process (loosen the screw and return focus ring further from infinity, tighten it again and test) as many times it takes to get real infinity.
Once you have infinity focus, loosen the screw again, try not to move helicoid by any other mean when turning zoom ring to a infinity mark. Then tighten all three screws back - you have done infinity focus adjustment.

Read more at: http://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/309272-tokina-rmc-80-200mm-f4-pk-mount-infinity-focus-adjustment-long-end.html#ixzz47lez6xzo

Now that i don't understand is what is and which is the focusing helicoid ? how can i don't move it ? I need to keep the front element ?

And also the phrase "Once you have infinity focus, loosen the screw again, try not to move helicoid by any other mean when turning zoom ring to a infinity mark. Then tighten all three screws back - you have done infinity focus adjustment.", what means "try not to move helicoid by any other mean when turning zoom to a infinity mark." ?

This is that i don't understand, if someone has it more clear than me, let me know

Thanks again
mav_top

LifesShort · Joined: 01 Feb 2016 Posts: 71 Location: Forsyth, GA, USA

I believe you have more than just an infinity focus problem since you aren't able to focus at mid-range distances, either. I once experienced a similar problem to yours where I could focus up close, but not more than a few meters. It turned out that when I reassembled the lens after cleaning, I put one of the lens elements in backwards. Once I discovered and corrected the problem, the lens focused at any distance with no problems.

Is it possible that either you or a previous owner of the the lens installed one of the lens elements incorrectly?

mavtop · Joined: 10 Apr 2016 Posts: 32

it is possible that the previous owner did it.

I payed a lot of attention when i disassembled the len.

I removed all the front elements, but i didn't remove the rear elements.

The front element were cleaned (they were already very clear) by me and i put them in their position.

I need the croce point screwdriver to remove the rear mount and have access to the rear elements easily.

Only in this way i can see if something is in the wrong position.

Repeat all the front elements are forced to stay only in one position, some have a tread which can be used only in one way.

mav_top

mavtop · Joined: 10 Apr 2016 Posts: 32

Yesterday night i successed to remove the rear mount, but then i stopped because at the beginning i had some problems remounting it with the aperture blades, so after removing it 2 times and looking better i discovered (maybe) how to fix it and i fixed, now the len aperture ring works again.

But for now i closed the rear part, i want to be sure i need to verify it, before disassemble the rear elements.

Anyway all seems at the right place for now, so i mailed to tokina japan for some help, some optical scheme or repair manual, or hints.

Hope they will answer.

mav_top