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Posted by Steve King on 12/21/07 15:43
"David Ruether" <druether@twcny.rr.com> wrote in message
news:476bd934$0$28837$4c368faf@roadrunner.com...
>
>
> "Spex" <No.spam@ta.com> wrote in message
> news:13mnl5ed2rmie38@corp.supernews.com...
>> Steve King wrote:
>>> "David Ruether" <xxx> wrote in message
>>> news:476af1cb$0$11001$4c368faf@roadrunner.com...
>
>>>> Canon certainly got their act together on this one
> [...]
>>>> --DR
>
>>> Okay. I'll admit that I am not much of a techy, when it comes to
>>> photography and lenses. So, I had to look up 'WA'. Google is >> my
>>> friend: Cocaine Anonymous, or a virus solution, or the state of >>
>>> California, or Chartered Accountant, or Certificate Authority, or >>
>>> Computer Associates, or the chemical symbol for Calcium. I think I'll
>>> go with calcium. Grrrrrrrr!
>>>
>>> Steve King
>
> I guess I assumed that common-usage of WA for "wide-angle"
> and CA for "chromatic aberation" in this NG (ah, "news group"...;-)would
> save space - only to find that a transferred single-spaced
> Word doc. became a double-spaced post...;-(
>
>> I think you meant CA not WA
>>
>> Chromatic Aberration.
>>
>> Around contrasty areas you'll see green and purple or blue and red lines
>> caused by the refracting at different wavelengths. It has always been
>> there just not as obvious in the low res world of SD.
>>
>> Lens can be coated to reduce this but it can lead to ugly bokeh if the
>> lens is over optimised.
>
> It is a lens design (or alignment fault) characteristic, not a matter
> of coatings...
>
>> I believe the new Sony EX1 actually corrects CA in the DSP which is
>> another completely valid way of reducing its appearance. I can also be
>> fixed in post by rescaling the R,G&B components.
>
> Yes - neat!
>
>> The standard Canon XL-H1 lens was the worst offender I've ever > seen for
>> CA.
>
> The original Canon XL-1 lens was no "gem", either, good as some
> Canon lenses can be...
> --DR
I did mean CA. Thanks to all for furthering my education.
Steve King
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