[Cerebum]

I have an Auto Rikenon 28mm f2.8 with what appears to be fungus on one of the rear elements. Is this an easy fix? Is it best to strip it from the back? And what is the best cleaning solution? I have never done this so any help or guidance would be well received. It has really good reviews on PF, otherwise I wouldn't bother but I am not an engineer, so, heeeeelp

Attached Images

 

[Sandy Hancock]

Put it in a sealed bag, and burn it

[Cerebum]

Put it in a sealed bag, and burn it

That is vying to be option 1 I have a nice chinon 28mm (the super sharp one) and a tokina that is a gem. I also have a soligor 28mm made by sun so I wouldn't miss the rikenon, but, if it as good as the reviews say .....

[VoiceOfReason]

If you already have 28mm lenses what's to lose in trying?

[ramseybuckeye]

If you do, make sure you have JIS screw drivers or you will damage the screw heads. Have some way to keep the screws in, magnetism works well. The screws are tiny. take pictures of each step. You may need a spanner. You need a well lit work table. Good Luck!

[ismaelg]

If you decide to try it (and I encourage you to), carefully disassemble from the back noting the orientation of the parts as you take them out. Once you get to the offending glass use Hydrogen Peroxide liberally. It may not get back to mint if there is some etching but it will improve. Make sure it is clean and dust free with a microfiber towel and put it back together.

*EDIT* As noted before, JIS screwdrivers are a must. Regular cross point may work but you risk stripping the screws.

Thanks,

[DWS1]

I would try to clean it myself. Nothing to lose. There all several quality 28/2.8 lenses available at a good price.

[Michail_P]

What about UV? I’ve heard of this, doesn’t it work?

[Cerebum]

If you already have 28mm lenses what's to lose in trying?

Thats true

---------- Post added 11-15-20 at 11:56 PM ----------

If you do, make sure you have JIS screw drivers or you will damage the screw heads. Have some way to keep the screws in, magnetism works well. The screws are tiny. take pictures of each step. You may need a spanner. You need a well lit work table. Good Luck!

I have a big rack of jis screwdrivers that I bought but barely use, time for a play

---------- Post added 11-16-20 at 12:00 AM ----------

If you decide to try it (and I encourage you to), carefully disassemble from the back noting the orientation of the parts as you take them out. Once you get to the offending glass use Hydrogen Peroxide liberally. It may not get back to mint if there is some etching but it will improve. Make sure it is clean and dust free with a microfiber towel and put it back together.

*EDIT* As noted before, JIS screwdrivers are a must. Regular cross point may work but you risk stripping the screws.

Thanks,

It looks quite faint, I am hoping this means it is at the early stages, although there is a possibility it has been cleaned and what I am seeing is etching and not fungus. The operation of the lens is suspiciously buttery smooth lol. I need to buy some hydrogen peroxide. Where to get that during lockdown. Hmmmm. Thanks

---------- Post added 11-16-20 at 12:01 AM ----------

I would try to clean it myself. Nothing to lose. There all several quality 28/2.8 lenses available at a good price.

That's the way I am heading. Worst case, I get some practice at stripping and reassembling

---------- Post added 11-16-20 at 12:02 AM ----------

What about UV? I’ve heard of this, doesn’t it work?

I think that works at killing fungus, say when you have a little bit that doesn't affect image quality, but in this case it needs cleaning

[HarisF1]

Just wipe the fungus off with a bit of condensation (breathe on it) and a clean cloth. No need for any fancy chemicals.

For a lot of lenses the front and rear elements are separated by the aperture blades, so if your fungus is in a rear element then you need to disassemble from the back. When you open it up you might ne able to move the aperture blades out of the way using the lever in order to clean the rear surface of the front element group.

Just start at the back with a lens spanner and make your way through the lens. Reassemble the rear elements and then start from the front if there is still some fungus left over.

[Astro-Baby]

Dont know the lens but would guess a lens spanner will be needed.

With luck the rear lens will unscrew in one block but you will need to get a lens spanner on it.

Once out the approach would be just a drop of hydrogen peroxide and wipe gently with a cotton bud. Flush lens with water and blow dry and final polish with lens cloth.

If its a cemented double go very easy with it and dont immerse it in anything.

[ZombieArmy]

I mean what do you have to lose by trying I say.

[Cerebum]

Just wipe the fungus off with a bit of condensation (breathe on it) and a clean cloth. No need for any fancy chemicals.

I like the idea of trying a good wipe first before hitting it with chemicals I can do that now, and if it doesn't work, I will go shopping

---------- Post added 11-16-20 at 02:15 AM ----------

Dont know the lens but would guess a lens spanner will be needed.

With luck the rear lens will unscrew in one block but you will need to get a lens spanner on it.

Once out the approach would be just a drop of hydrogen peroxide and wipe gently with a cotton bud. Flush lens with water and blow dry and final polish with lens cloth.

If its a cemented double go very easy with it and dont immerse it in anything.

Thanks I have unscrewed the rear ring that needed an improvised lens spanner but that just gave me the rear element bi need to get my screwdrivers and get the mount off

---------- Post added 11-16-20 at 02:16 AM ----------

I mean what do you have to lose by trying I say.

Nothing its currently a paperweight and whatever I do, it will still be a working paperweight lol

[ZombieArmy]

Nothing its currently a paperweight and whatever I do, it will still be a working paperweight lol

That's the spirit!

[Sam_I_am]

Take pics as you go please. It will be a learning experience for me anyway.