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- Path: sparky!uunet!usc!sdd.hp.com!nobody
- From: johno@sdd.hp.com (John Ongtooguk)
- Newsgroups: rec.photo
- Subject: Re: What does ED glass really buy you?
- Date: 22 Jan 1993 18:39:22 GMT
- Organization: Hewlett-Packard, San Diego Division
- Lines: 19
- Distribution: na
- Message-ID: <1jpf0qINNs48@hpsdlss3.sdd.hp.com>
- References: <1993Jan21.094446.12281@sactoh0.sac.ca.us> <1993Jan21.173218.28028@cbnewsm.cb.att.com> <1993Jan22.003824.1054@cbnewsm.cb.att.com>
- NNTP-Posting-Host: hpsdlg10.sdd.hp.com
-
- In article <1993Jan22.003824.1054@cbnewsm.cb.att.com>, ka1gt@cbnewsm.cb.att.com (robert.m.atkins) writes:
- |>
- |> I should point out that there are two types of chromatic aberation.
- |> One is longitudinal chromatic aberation which results in a different
- |> focus for each wavelength. I need to think about this some more, but
- |> maybe stopping down does reduce this?? I'm not sure.
- |>
- |> The second is lateral chromatic aberation (lateral color) in which the
- |> difference in focal length for each color results in a different
- |> magnification for different colors. This is not influenced by aperture
- |> and so stopping down doesn't help.
-
- I recall reading a review of some Rodagon (?) apo enlarging lens
- which were very well corrected for color but focused colors at
- different points, which I guess means that the lateral color
- was minimal but was optimized at the expense of longitudinal
- color ?
-
- John Ongtooguk (johno@sdd.hp.com)
-