as some Carl Zeiss E-Pl eyepieces purchased in the U.S. have been identified as coming from the manufacturing contracted in the Far East, it may be important to have an identifier for the country of origin.
The identifier can be found on the wrap with the documents, when not available, then on the plastic canister.
The canister on the pic shows:
- The item number, like 444232-9902 which is also engraved on the eyepiece body
- The product name Okular E-Pl 10x/20 Br (for glasses wearers) foc (focusable)
- The next row shows the traceability code for the quality control QS (Qualitätssicherung)
The second sticker refers to the accessory mounted in the eyepiece for delivery. In this case it is the reticle with a cross.
The production of the Carl Zeiss E-Pl eyepieces has been “iterated” over their production lifetime. Herewith the glass materials and AR coatings have changed, as my collection documents.
The next close eyepiece to the Carl Zeiss E-Pl 10x/20 Br foc is the LEICA
The both eyepieces have the same basic optics design after König, (field stop – 2 - 1).
The Leica proprietary glass materials with the higher refractive index and a still lower dispersion, have made it possible to materialize the eyepiece optics with smaller surface curvature lenses.
In practice, the both eyepieces have the same field of view, the same focus, and are parfocal. Herewith, I can swap Leica against Zeiss on my Zeiss STEMI stereo microscope without any difference.
On my refractor, the Leica eyepiece shows a higher contrast on the faint low surface brightness nebulae and galaxies, Zeiss passes more light at the blue wavelengths shorter than 436nm, which is helpful on the galaxies with the blue color index.
Thank you for reading and looking,