Foggy element on Zuiko OM zooms?

[Philipp500]

I read a posting where someone wrote about an irreversible fogging of an element of an OM 35-105. Now I do have

two 65-200/4 which both show the same problem. Is it really irreversible? Anyone can help? Thanks a lot

[harold_gough]

In what circumstances did this occur? Was it sudden? Were the lenses subjected to the same conditions?

[tommyinca]

If the fogging is caused by the coating seperating or breaking up, not much you can do (ie. like many Computar enlarger lens) outside of removing and recoating it. You will need expensive equipment and process. Couple years back, there is an outfit in Russia that can do it at reasonable price. Not sure now. If it is caused by element cement seperation, it is easier to do but still expensive and hard to DIY.

[tommyinca]

BTW: Chances are it is not above. In which case, taking the elment out plus cleaning should do it and are much easier. Do mark everythings so putting it back together is easier. Zoom lens are much harder.

[john_hicks5]

It's probably vaporized lubricants deposited on the element, certainly cleanable, or of course could be fungus haze. Send the lenses to a reputable shop for cleaning. Really bad fungus, peeling coating or separation are essentially unrepairable for a reasonable cost.

[konrad_beck1]

It's new to me that the 35-105mm lens would have a common fogging problem, but for the 65-200/4 (and it seems that the 50-250/5 is en route), fogging of the second element from the rear is so common that you can buy another ten to have the chance to get one clean one (I might exaggerate, but only a little). Cleaning seems not to help: if it can be cleaned, the fogging will be back in a couple of month. As John Hicks suggested, it might be due to evaporated lubricants, and these can also etch the surface.

 

Are your two lenses early or late samples (serial number = ...) ? I think the 65-200/4 was produced up to at least 1990, i.e. longer than the 50-250/5, and it could be that late samples might not have this problem due to better lubricants?

[Philipp500]

Thanks a lot for your contributions. The lenses are 111320 and 119908. The 35-105 was mentionned in an older posting which actually was not about the fogging. It seems indeed that it is one of the rear element which is affected. Both lenses show very much the same regular and soft fogging. I'm pretty sure contrast must be less with that problem and as I read you, I'm not sure whether it will be worth having the lenses fixed since it may reappear soon? Somebody is offering me a new lens - boxed - for a decent price, but I haven't seen it. Any possibility the same problem may be present even there? I'll never try to fix it myself anyway, too scared...

[john_hermanson2]

I have not ever seen the element fogging issue in the 35-105 zoom. I have seen it in the 65-200 and 50-250. I don't remember exact details as to which lens, but sometimes outer surface of element, 2nd or 3rd from the rear, takes on an etched finish. Other possible symptom might be 2 elements glued together ( a group) becomes unglued. Though problem might be caused by migrating oil (separating out of the focus grease) it is not something that will just clean off. Damage is permanent. New parts not available. John, www.zuiko.com

[konrad_beck1]

Your serial numbers indicate that these lenses were produced in the early period in 1983 and 1984. Over the weekend, I have checked that my 1513xx has not (yet?) build up any fog. However, a database indicates that even later lenses (154xxx from 1989) have fog problems, so my earlier assumption that this problem might have been solved by Olympus over time seems unfounded.

[Philipp500]

Looking carefully at the problem, it really doesn't seem to be elements which got unglued, but much much more like some very regular (!) and even spraying of something onto the element. I check it by looking through the lens from the front against the sun, (of course, carefull not to get the sun itself in the field)

[Philipp500]

To Konrad Beck. I would be very interested in being able to determine the age of my Zuiko lenses (all of them) according to serial number. Do you have such infos? Thanks

[konrad_beck1]

Here is an explanation for determining the age of Zuiko OM lenses produced after mid 1983:

 

http://www.photo.net/olympus-camera-forum/0063Yx

 

Be aware that the abscence of this 4-digit code does not mean that the lens is produced earlier. There seem a couple of lenses where this code was not applied.

 

Lenses marked "ZUIKO" only (not "ZUIKO MC" or "X.ZUIKO" with X = E, F, G, H) are usually produced after November 1981 (again, some exceptions).

 

For many (again not all) lenses produced before mid 1983, a 3-digit code can be found below the focus ring rubber: 1st Katakana or roman letter = production plant, 2nd digit = last digit of production year (e.g. "7" = 1977), 3rd digit or letter = production month (X,Y,Z, for Oct - Dec).

 

Your 111320 lens should have a white code at the back reading TNCC or TND1, the 119908 TND2 or TND3 (I might be wrong by one or two month, but not more).

[ondrej_p.]

<p>I also had a 65-200 with foggy element and just last night I managed to clean it. The most difficult part is getting to the foggy element, because it's the middle of 5 element group.<br>

http://esif.world-traveller.org/om-sif/lensgroup/65-200mmf4.htm<br>

However the group can be unscrewed from the back of the lens after removing the mount and aperture ring, and then carefully disassembled. Some elements are not distinctively convex or concave so be sure to put them back the correct way. The middle element is removable from the front.</p>