Removing fungus from old Porro binoculars (2 Viewers)

[Barbican1987]

I bought a pair of Porro 10x 50. Charity shop for £15 recently.
They aren't waterproof and it looks like there is some fungus growth on the inside of the objective lens.

They are Japanese optics with fast focus lever sold by Boots the chemist in the UK. They are clearly generic badged by Boots but made by a Japanese company. Just found original Japanese manufacturer Kamakuri Koki from a previous thread listing all JB numbers of Japanese Binoculars ( hence prefix JB I guess!!)

They are not valuable and I wondering if it's possible to remove the Objective lens and clean off the fungus and replace the lens.

I am not really bothered if it fails but just wondered if anyone has any experience who can advise me how to go about this please.

 

[Binocollector]

If the fungus is only on the objective lense, it should be quite easy. Simply unscrew, remove the fungus and put back on. It's much more annoying if the fungus is on the prisms -- those are often cemented in place, so you'd have to remove the cement, remove the prism(s), remove the fungus and re-assemble everything + re-align.
Can you upload a pic?

 

[Barbican1987]

If the fungus is only on the objective lense, it should be quite easy. Simply unscrew, remove the fungus and put back on. It's much more annoying if the fungus is on the prisms -- those are often cemented in place, so you'd have to remove the cement, remove the prism(s), remove the fungus and re-assemble everything + re-align.
Can you upload a pic?

Thanks Phillipp,
They look similar to some Swift models. The number JB 133 plus serial number is shown . Looks like there is a screw threaded clip which keeps the lens in.

Photo doesn't show fungus very well but I have cleaned the exterior of the lens and something still shows on the inside.

Just found manufacturer on previous Bird Forum thread.
Kamakuri Koki it seems.

 

[Patudo]

There is a book written by one of the regular posters here that should give you chapter and verse...

 

[Binocollector]

I have a very similar Kamakura model in 8x40. On mine the whole objective can be unscrewed with the lense inside. And mine have no eccentric rings, so alignment shouldn't be affected. But you could check that by looking through the bino while carefully unscrewing the objective a half rotation. If the alignment changes, then they do have eccentric rings but if you screw them back on, alignment should be fine if they are in the same position as before.

 

[Maljunulo]

Make index marks before you unscrew anything, and keep track of how many turns.

 

[Barbican1987]

I have a very similar Kamakura model in 8x40. On mine the whole objective can be unscrewed with the lense inside. And mine have no eccentric rings, so alignment shouldn't be affected. But you could check that by looking through the bino while carefully unscrewing the objective a half rotation. If the alignment changes, then they do have eccentric rings but if you screw them back on, alignment should be fine if they are in the same position as before.

Thanks Phillip

 

[Barbican1987]

Make index marks before you unscrew anything, and keep track of how many turns.

Thanks Maljunulo

 

[Barbican1987]

Make index marks before you unscrew anything, and keep track of how many turns.

Thanks Maljunulo

There is a book written by one of the regular posters here that should give you chapter and verse...

Can you give me details please