Kodak Ektar 203 mm - fog/moisture in rear element

[Nitish Kanabar]

A recently acquired Kodak Ektar 203 mm come in a stuck Supermatic shutter. I removed the front and rear elements to give the shutter the ronsonol treatement. Since the elements were quite dirty as well, I cleaned the each surface of the front and back elements with Schneider photo-clear cloth and solution. Upon cleaning the back element, I noticed a tiny disk of fog/moisture in the center and *inside* the back-element. I waited a while and the fog disappeared. I'm sure that it was not on the surface and I cannot see any separation or haze now. What is this transient fog inside the back-element a symptom of?

thanks in advance,

[Patrik Roseen]

It could be that what you saw was actually fog. If the lens cleaner formula is such that it quickly vaporates, i.e. dries of, then it will consume energy and cool the glass surface which in turn could cool the air inside the ektar lens and create the fogging in the airspace between the two elements in the rear lens. I do not know if this is normal or not but maybe there is a leak in the lens where the glass is attached to the lensbarrel.

[Dave Henry]

Also, never apply lens cleaning agents directly to the glass on a lens. Always apply it to a cloth or tissue first, then clean the glass. Applying directly to the glass allows the cleaner to migrate around the mount and enter the edges of the glass. There it could possibly work its way between the elements and cause damage.