ridgebackpilot
Member
Today I received my new pair of pristine condition Leitz 7x35 BA binoculars from @DLedig (thanks, Dave). They are amazingly bright and clear for a 32-year old binocular! This pair dates from 1986 (s/n 964920) and I was curious whether they might have received one of the early phase-correction coatings that were just being developed in the late 1980s.
So I decided to perform the polarizer test: Against a white LCD laptop screen, look through the objective end of the binoculars while wearing sunglasses with polarized lenses. You can also use a polarizing filter for a camera lens if you don't have polarized sunglasses.
When you rotate the binoculars or the polarizing lens, you'll see one of two things: If half the view goes dark blue/black and the other half is clear, the binocular does NOT have phase-correction coatings on its prism.
If the view stays mostly the same with only a faint line across the middle, the binoculars DO have phase-correction coatings.
In my case, I'm sorry to report that my Leitz 7x35 BA do NOT have phase-correction coatings. For comparison, I also tested my modern Zeiss Conquest HD 10x42 as well as my Zeiss TL 10x25. Both of them clearly do have phase-correction coatings.
This test seems an unmistakable way of determining whether or not your binoculars have phase-corrective coatings.
So I decided to perform the polarizer test: Against a white LCD laptop screen, look through the objective end of the binoculars while wearing sunglasses with polarized lenses. You can also use a polarizing filter for a camera lens if you don't have polarized sunglasses.
When you rotate the binoculars or the polarizing lens, you'll see one of two things: If half the view goes dark blue/black and the other half is clear, the binocular does NOT have phase-correction coatings on its prism.
If the view stays mostly the same with only a faint line across the middle, the binoculars DO have phase-correction coatings.
In my case, I'm sorry to report that my Leitz 7x35 BA do NOT have phase-correction coatings. For comparison, I also tested my modern Zeiss Conquest HD 10x42 as well as my Zeiss TL 10x25. Both of them clearly do have phase-correction coatings.
This test seems an unmistakable way of determining whether or not your binoculars have phase-corrective coatings.
Last edited:
