Seperating elements on N24-85 VR

[Pistnbroke]

I purchased a 24-85 VR for about $40 us  as it had a small transparent spot (4mm) of fungus under the front element. Investigation shows that the fungus is between the  two lenses that form the front element. It seems to be spun into  metal mount ( have lathe).

While it works fine is there anyway to separate the two lenses and re cement ?  Or is there any way to kill the fungus UV  etc.

thanks in advance

[Birna Rørslett]

A 'healthy' dose of UV, for example from the sun, will kill the spores and prevent the fungus from further  spreading. However, the hyphae won't disappear immediately and might persist for a very long time.

[Pistnbroke]

Thanks for that ..how long would you recommend in full sunlight

[Birna Rørslett]

A week? Really, there is no predefined answer. The longer the better.

Just remember the lens can focus sunlight and cause a fire. Thus be careful not to place it with combustible material to its rear. And do remember to keep an eye on the weather forecast. Drowning a lens in a sudden downpour is conducive to augmented fungal activity.

[Matthew Currie]

As an added note, I have a 20/2.8D lens which had fogging between the elements (too bad to use), and I took it to a local repairman who separated the elements and re-cemented them.  It's something he's done in the past with success, and he knows how to do it and to align the elements and so forth.  All clear now, but unfortunately the new cement apparently has a different index of refraction from the old, and the lens is soft. Not too awful if you don't look closely, but soft enough to be counted as a loss for which he ended up not charging.  So I'd give the treatment above a good long trial before trying to separate elements.

[Chulster]

Since the lens is still being manufactured, perhaps you could send the lens to an independent repair shop and have them just replace the front group? People scratch and crack front elements all the time, so this should be one of the cheaper repairs. Might even be cheaper than the labor to un-cement, clean, and re-cement the two elements.

[Nasos Kosmas]

I don thing it’s fungus between the two front elements, fungus needs moisture to grow, in this part of cemented glasses nothing can get in so it’s something else, can’t you live with it?
Otherwise go to Nikon repair house as suggested

[Pistnbroke]

I have had the front element out and its between  the two.  Dark centre spot and a spiders web around it. So must have got in during manufacture ( ? )
Although it looks silvery from the front looking through the lens its transparent . As the lens cost only $40 and it will work with a Z series (should Nikon ever produce one that will focus) I think its worth keeping as is .At present its on a UV lamp  24/7  awaiting the Z8 or D860

[Toby]

If it looks silvery from an oblique angle but transparent front on, it is most probably delamination--balsam separation.

[Erik Lund]

Please share an image close up of the issue.


Thanks