Wollensak 330mm Triple Convertible Lens

[Will Ewing]

I bought my Wollensak from Sandy King (as he mentioned above) and I think if that had been my first lens, it would have been my only lens. I have a 14 inch Dagor that has only a slight edge of contrast over the Wollensak at 13 inches. The individual elements are really quite good...if you contact print you will wonder why anyone would spend the big bucks for an Artar... Under a loupe the Artar will win, but unless you enlarge it is hardly an issue... the difference in price will buy a lot of Azo. Good luck

Will

[sanking]

Hi Will,

Glad to see you are still getting good use from this lens.

BTW, Wollensak made the 13"-20"-25" triple convertible for a very long time. The early version was called a Velostigmat 1a, and was not coated. Later versions are called Raptar 1a and are coated. Like Dagors the Wollensak triple convertible only has four air-to-glass surfaces so contrast is very good, even on the older non-coated version. The coated convertible Raptar has excellent contrast, better than older single-coated Symmars.

I agree with Jim. These lenses are real sleepers and the ones I have used compare very favorably to the Protar VIIa, except for coverage where the protar has a slight advantage.

Just so there is no mis-understanding, my reference to lack of coveage was in refrence to 11X14 and 7X17, where this lens just misses. For 8X10 use it would give ample coverage, with quite a bit of movement, even with the single elements.

[sanking]

A few words about using the single elements. The single elements are not quite as corrected as the two elements combined so it is always recommended to stop down the lens two or three stops, which will greatly reduce many of the lens aberrations, including astigmatism, coma, and longitudinal chromatic aberration.

However, stopping down will not improve lateral chromatic aberration, which in effect produce color images of different size. For this you should use a filter that cuts one of the colors. The best filter for this, IMHO, is a light orange filter, since the worst offender tends to be blue light.

The above applies equally to other convertible lenses, such as the Protar Series VIIa, the Gundlach convertibles, and the convertible Symmar.

[J. P. Mose]

Strange...my prior posting thanking all of you for your infomation is before your responses! I don't have a crystal ball...I posted that after Sandy King's final posting. Cyberspace I will never understand.