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wfhguy · Posted: Sat May 12, 2001 4:22 pm Post subject:

I was inspecting an Ektar 127mm lens recently, thinking of replacing my 127mm Optar. On close inspection, the Ektar had several bubbles in the glass. Is this common for Ektars or is it a fluke? I'm surprised a lens with bubbles would make it through quality control.

Les · Joined: 09 May 2001 Posts: 2682 Location: Detroit, MI

small bubbles in glass in common, some people believe it's a sign of better glass, since the bubbles are formed by mixing more than one type of glass in a molten state. If the bubbles are spherical, there is no problem.

I have a lens made about 1840 that show distorted bubbles, which are a sign of striation (incomplete mix of the glass types) This leads to image degredation

wfhguy · Posted: Sun May 13, 2001 6:21 pm Post subject:

How is it that bubbles wouldn't degrade the image? Wouldn't the light be scattered and distorted as it passes through? Thanks...

Les · Joined: 09 May 2001 Posts: 2682 Location: Detroit, MI

I'm not sure why, but all I know is, you won't be able to find the difference with a 7x loupe on a 4x5 transparency.

I think it might be the ratio of the size of the bubble to the size of the glass, ie not enough rays of light getting scattered.

wfhguy · Posted: Sun May 13, 2001 11:19 pm Post subject:

That makes sense...thanks for the info!

brushworker · Posted: Sun Aug 26, 2001 7:56 pm Post subject:

My 1947 Ektar 127mm lens has me stumped. Where can I get a 38mm polarizer for my series 6 filter adapter? B+H does not seem to carry this or any series 6 filters. Is there any field-expedient solution out there?

Henry · Posted: Mon Aug 27, 2001 12:16 am Post subject:

Dear Brush,
I'm not sure what size Series VI slip-ring fits a 127 Ektar (is it the 38mm you mentioned?), but if you already have the slip-ring then you're half-way there. The thread in your Series VI slip-ring is 44mm. Obtain a 44-49 step-ring (or 44-52, 44-55 etc.) and you can use a 49mm (52, 55, etc.) polarizer directly on this adapter set-up. Or look for a Series VI polarizer---I found a mint Spiralite recently at a camera show---it will already have the 44mm thread and will screw right into the Series VI directly. Caution: older polarizers seem to develop permanent fog spots in the glass, so make sure any used polarizer is really clean! In general, camera shows are the best places to look for all this sort of discontinued stuff. Since you're in northwest Jersey there are camera shows several times a year, in the Delaware Valley-Philadelphia area, also in the metro NYC area.
Check Shutterbug magazine for listings.
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[ This Message was edited by: Henry on 2001-08-26 17:22 ]

leski · Joined: 06 Sep 2001 Posts: 2 Location: Nortwest NJ

Bless you, Henry,

And thanks for your information. Sorry to reply so late. Been away. Yes, it's the 127mm Ektar (1947) and I now understand 38mm is the slip-on size. Hope to get my 44-52 step-up in the next few weeks.