[geekette]

I got this set of Japanese made coated macro lens filters--part of the pentax bundle I got yesterday for $25.

They seem really heavy, crystal clear & coated with that purplish coated tint at certain angles--they look lovely. There doesn't seem to be a brand name not even on the instruction sheet. They are in great condition and I have already tried them out.. I just don't know what brand they are--please help

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[RioRico]

Without a 'name' brand, they could be from anyone, anywhere. These were churned-out by the zillions by almost anybody who could grind glass. They are close-up adapters, not really macro. They reduce the focusing distance of whatever lens they're strapped-onto. Here is some info I found in the "The Pentax Way" by Herbert Keppler:

"Generally speaking a +1 lens focuses from 20" to 38"; a +2 from 13" to 20"; a +3 from 10" to 13"; a +4 from 8" to 10"; a +5 from 6.5" to 8"; a +6 from 6" to 6.5"; a +8 at 5" and a +10 at 4". The focusing distances are not dependent on focal length. No matter what lens you use on your camera, subject distance with the same close-up lenses remain the same. Naturally, the area covered varies with the focal length of the lens and the image size will be greater with the lens of longer focal length."

Thus the close-up attachment lens diopter selects the working distance, while the focal length of the lens the close-up lens is attached onto determines magnification.

+1 >> 20-38" (500-950mm)
+2 >> 13-20" (330-500mm)
+3 >> 10-13" (250-330mm)
+4 >> 8--10" (205-250mm)
+5 >> 6.5-8" (165-205mm)
+6 >> 6-6.5" (153-165mm)
+8 >> 5" --- (127mm)
+10 > 4" --- (102mm)

Unlike 2-element Raynox and Canon adapters, these are simple meniscus lenses, quite uncorrected for optical aberrations. They can be usable when you 1) don't care about edge IQ, 2) don't have anything better, or 3) actually want their low-fi effects. A +1 dioptre can turn a slow prime into a moody portrait lens. They can be stacked to increase the dioptres -- +1+2+3 = +6. But the more they're stacked, the softer they get. Try some test shots and see how they work. They're cheap, and they can be fun! Just don't expect anything like great quality from them.

ADDENDUM / PERVERSION: I recently got a +10 dioptre close-up that I can stack onto my Raynox DCR-250 (+8 dioptres) along with a +2 dioptre, and mount on a short M42 macro tube. +20 dioptres = 50mm. (Divide 1000 by the dioptres to get the focal length.) The aperture of the Raynox is about 36mm. 50/36= 1.38. So I have a 50/1.4 fixed-focus lens for like REAL CHEAP. (A focusing helicoid would be nice to have, but those are expensive.) And it is SOFT! When another +10 dioptre arrives, I can take that to +30 dioptres = 35mm at f/0.9! Fastest glass around! And no, I won't expect anything like quality from that combo. Are bad optics worse than no optics at all?

[geekette]

Rico, wow thanks for the help!--I learned a lot there! Oh, btw I found out these are Tiffen brand.

[efe9]

looks like old Supreme filters