An early Christmas present to myself. I probably paid too much for them, but these don't seem to turn up very often on the 'Bay, and I was regretting not buying the 90X Apo that sold a while back.
This seller has a good feedback rating, and received positive feedback for recent sales of objectives and microscope parts.
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Adding the 20x from the set I already have, I now have a set of 4 of these gold plated apochromats.
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I really only wanted a 90X to replace the one in my existing set, because it has real bad delamination in the upper group and gives a very poor image, not usable. But my existing 43X apo was also not in perfect condition. There is a touch of delamination around the very outer edge of the upper group, but also some localized delamination near the edge of the group just above the bottom plano convex element. And although localized to one spot, it extended in a ways toward the center. Actually, it looked kind of bad looking at it with a magnifier toward the light, but image quality is excellent as far as I can tell. My existing 10X and 20X apochromats are in perfect condition, as far as I can tell.
These lenses are from an older series, with serial numbers beginning with the letter B. My existing set have numbers beginning with the letter C.
One thing interesting is these older lenses are almost a whole millimeter longer than their counterparts in my existing set. I found this out right away when using my existing 20X objective with these new (to me) ones. Comparing them side by side it's easy to see.
These new to me lenses perform great, especially the 90X. It is sharper than any of my other oil immersion achromats, and the antique fluorite objective as well. I was kind of surprised, though, at the curvature of field, as great as my achromats, and slightly greater then the old fluorite, but sharper.
Not complaining though, it was made before plan objectives came on the market (as far as I know), and looking at the sharp image with the slight fuzziness seen through the achromats removed is very satisfying.