Ball bearing could be dirty / rusty. See ring (page 1 of parts list,
D2) CF9799 which may be loose.
___________________________________
John Hermanson | CPS, Inc.
21 South Ln., Huntington NY 11743
631-424-2121 | www.zuiko.com
Olympus OM Service since 1977
Gallery: www.zuiko.com/album/index.html
On 2/21/2011 5:58 PM, Chuck Norcutt wrote:
> From the parts PDF it appears there is a small spring and detent ball
> that presses on the back side of the ring towards the lens mount. When
> you pull back on the ring you are compressing the spring and probably
> compensating for dirt and/or lack of lube.
>
> You can get a copy of the PDF from Mark Dapoz's site here:
> <http://olympus.dementia.org/Hardware/PDFs/35-80mm_f2.8.pdf>
>
> See the first page and the third ring from the right in the top row.
> The second ring is the aperture ring. Note spring part number CA071500
> which is recessed into the third ring and what I assume is the detent
> ball, part number WE201036 which presses on the back side of the
> aperture ring.
>
> If I had to guess I'd say it probably just needs to be cleaned and given
> a teeny dab of grease so the ball can slide smoothly on the backside of
> the ring. My 28/2.8 had a similar problem and wouldn't open wider than
> f/5.6. Cleaning followed by that teeny dab of grease worked miracles.
>
> Chuck Norcutt
>
>
> On 2/21/2011 4:43 PM, SwissPace wrote:
>> I haven't yet been brave enough to remove the rear mount yet, but after
>> more inspection I discovered that the aperture adjust ring has play
>> front to back and that if I slide it back towards the camera I can turn
>> the aperture ring and then when it "springs" forward again it locks the
>> ring again. I assume is not some new feature I have found but it seems
>> to be quite useful :-) but more likely a bearing that has come out
>> although the good news is It seems that it hasn't affected the sharpness
>> of the lens as you can see in this image from this weekend.
>>
>> <http://thattimeoflife.smugmug.com/Portfolio/2011-Few-Fotos-For-Fun/15910940_2Y2hT#1194515466_BuWA5-L-LB>
>>
>> Is it tricky to work out where the bearing should go?
>>
>> Thanks
>>
>> IanW
>>
>>
>> On 2/18/11 7:50 AM, |-o-| wrote:
>>>>> . . . however the biggest casualty was my 35-80/2.8 which seems to be
>>> stuck on F8, I think the rear cap came off and maybe something got twisted
>>> as it bounced in my camera bag.
>>>
>>>> Unless the 35-80 is greatly different from other OM lenses, there's a
>>>> fairly
>>> simply part of the mechanism directly under
>>>> the mount. The area isn't particularly well sealed, so dust, dirt, etc.
>>>> could
>>> get in. Also, a couple of parts are fairly
>>>> flimsy. I've fixed 2-3 sticky apertures simply by working there.
>>> WATCH OUT for bearings dropping out.
>>>
>>> As Moose offers, look under the mount first. The aperture ring for that
>>> lense also uses a couple (or more ?) bearings. I had to dismantle my old
>>> 35-80 once when the bearing came out of the track due to loose mount
>>> screws, once I got the bearing back in the right spot the Aperture worked
>>> fine again, and didnt wobble between the front and rear of the lens.
>>>
>>> Cheers
>>> Ian Manners
>>> Power corrupts...Absolute Power is kinda neat...
>>
--
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