Re: [Leica] Anomalous partial dispersion

["Gerry Walden" <gerrywalden@cwcom.net>]

My understanding of this phrase is that they both disperse elements of the
light rays as they pass through, but the dispersion is such that the effect
of one lens is cancelled out by the opposite effect of the other lens.   I
would stress that this is my personal understanding with no scientific basis
or knowledge based on being around a long time - but I could be totally
wrong!

Gerry


- ----- Original Message -----
From: Anders Nygren <anygren@attglobal.net>
To: Leica Users <leica-users@mejac.palo-alto.ca.us>
Sent: 23 March 2000 04:56
Subject: [Leica] Anomalous partial dispersion


> Hi
> Finally I got a trip from Mexico to Miami where I spent one day
> visiting some camera stores. I was looking for a I thought that
> I was looking for an Elmarit 90 or a Summilux 50 or a
> Skopar 25 or a Heliar. But I did not find it. However I found a
> APO 90 Asph. I always thought that it was MUCH to expensive
> but when I saw and handled it I realised that I had to have it.
> (And it is all Your collective fault, if not all the LUGGERs had raved
> so much about ths lens I might have had the strengt to "just say no",
> so thanks alot, I couldnīt have done it without You all.)
>
> So well back at the hotel I saw in the instructions that two elements
> have "anomalous partial dispersion", I have never heard of this
> before. Can someone, maybe Erwin, explain what that is?
>
> /Anders Nygren
>