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Performance of AS100

Started by echan1127, 01/24/2004 10:37AM
Posted 01/24/2004 10:37AM Opening Post
How is the performance of the AS100? More specifically, how would it fare in a side-by-side with a Tak FS102 or TV102?

Is the AS100 a triplet or doublet? Any help would be appreciated.
Posted 01/24/2004 01:09PM #1
Evan,

the AS 100/1000 is a doublet designed by August Sonnefeld at Zeiss during the 30'ies. It is a semiapochromatic objective based on a classic Fraunhofer (doublet with airspaced lenses). It consists of an outer crown and an inner flint element. Both are resistant to the normal air polutions. Until the early 80'ies Zeiss produced uncoated lenses. The newer AS objectives are coated.

It would not be "fair" to compare the AS to an FS objective by Takahashi. The FS is a fluoride doublet with a much better color correction. In fact the construction is very similar to the AS. It is als an airspaced doublet. But I think it is based of the design by Steinheil rather then Fraunhofer.

The AS lenses are extremely well corrected semiapochromates but they can not defeat a well corrected apochromatic objective. If you look for the "absolute" color-free picture it is not the right choice. But if you seek for a piece of fine optical design and finishing (and of course a collectible item) go for it!

Michael