Archived posting to the Leica Users Group, 2008/07/02

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Subject: [Leica] Chromatic aberration/fringing in spectacles?
From: Frank.Dernie at btinternet.com (Frank Dernie)
Date: Wed Jul 2 02:26:56 2008
References: <5.1.0.14.2.20080630204103.00bf2ec0@mail.2alpha.com> <04CFED8A-C5FA-4512-B5ED-4B37746C9501@comcast.net>

> FWIW I have varifocal lenses and the chart with the various choices  
> of lens material at my Optician has a column related to the  
> chromatic accuracy. The best of the optical plasics was not that  
> with the highest refractive index, but one in the middle. I chose it  
> for this reason, rightly of wrong. I do not see any fringing.
Frank

>
>
> On Jul 1, 2008, at 12:27 AM, Peter Klein wrote:
>
>> Optometrists or anyone who knows the subject:  I just go a new pair  
>> of bifocals. The distance prescription seems great.  But the  
>> reading lenses do something I've never experienced before.  When  
>> the  gave me a newspaper to check how I felt when reading, the  
>> contrast of the letters appeared noticeably lower my old glasses.  
>> Then I realized that large black letters had color fringing. I  
>> looked at a square picture which was mostly black, and I saw a  
>> reddish-amber fringe at the top, and a blue fringe at the bottom.   
>> Huh?
>>
>> The young guy fitting my glasses (a technician, not the optometrist  
>> who does my eye exam) first met my observation with silence. After  
>> I insisted several times that I was seeing the color fringes, he  
>> said that it might just be that I was not used to the new  
>> prescription, and the fringing would go away in time.  But he also  
>> said that because I got a frame that had no bottom wire, they had  
>> to use polycarbonate lenses rather than the generic optical plastic  
>> I'd had on my previous glasses, and this has slightly less good  
>> optical properties. He said that they could upgrade the lenses to a  
>> better material for about $30.  But he advised me to keep them for  
>> a couple of weeks first and see how I felt then.
>>
>>  The lighting at the optometrist's was a mixture of sunlight and  
>> incandescent light.  At home under tungsten light,  I am seeing the  
>> same fringing on black bars or squares on white paper. The fringes  
>> are always horizontal lines, not vertical. The fringing doesn't  
>> happen without glasses, or with my old glasses. Possible  
>> confounding factor: It was very hot in Sunday night, and I got very  
>> little sleep.
>>
>> Has anyone else ever seen this color fringing with spectacles? Any  
>> advice?
>>
>> --Peter
>>
>>
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>
>
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In reply to: Message from pklein at 2alpha.net (Peter Klein) ([Leica] Chromatic aberration/fringing in spectacles?)
Message from len-1 at comcast.net (Leonard Taupier) ([Leica] Chromatic aberration/fringing in spectacles?)