i was wondering What Balsam glue separation looks like? I've seen pics online in regards to severe cases. What I want to know or see is a normal view finder compared to view finder that has the start of seperation. No.. I don't have an issue with my cameras. Just want keep tabs on the condition on my gems.
I used to have a lens with edge separation, never saw it in the ground glass, and it was a really decent lens. I sold it with my 5x7 camera. It looked like air bubbles around the edge of the front element.
Separation begins around the edges of the two elements and progresses toward the center. It occurs when the resin used begins to dry out. Newer lenses use a synthetic cement that prevents the problem. It hardens but does not dry out. Lenses can be recemented but it requires a professional and special equipment. You need a vacuum chamber to prevent bubbles in the cement.
When the(if) the RF prism separates you won't see anything but framelines. The viewfinder goes black.
Doesn't help with seeing if there's any progression does it?
I just took a photo of my Symmar-S's separation in the rear cell. It's not always easy to find, but basically what you see is an extra surface appearing between the partly decemented elements. Since my lens is multicoated from 1978-1979, I wonder how resistant synthetic cement to drying out is.