Leica Leicavit 400mm televit lens- cleaning rear optics? Removal?

[jaques]

Advertisement (gone after registration)

I've just come across one of these lenses with a rifle type grip, etc. It's in perfect order except for some nasty dust on the rear element surface. It looks as if a very little fungus has sproted around each mote of dust. Doesn't look like it has damaged/etched the lens surface and should be easy to clean if it can be accessed. Is it possible for a layperson to easily remove open the lens and gain access to clean that area? And if so- how?

[dkCambridgeshire]

If you are referring to the Telyt R 400/5.6, it's a 2 element 'telescope' achromat lens group which unscrews from the front ... push the lens hood 'in' and with a firm anti-clockwise 'twist', the front lens group will unscrew ... there is a spacer ring surrounding the screw thread ... make sure it's replaced when reassembling. Clean the lens glass with Eclipse sensor cleaning fluid which will not leave any smears. 

[zeitz]

If you indeed have fungus, first wash the surface with 10 parts Hydrogen Peroxide to 3 parts Ammonia.  If you remove the cemented pair from the mount, all the better.  Just be sure you know which side is the front and which side is the back.  The fungus will be killed and removed.  In some cases damage from the fungus, such as in the coating, will remain.  Then clean as above or with lens cleaning fluid.