Re: PESO - 400 mm portrait

[P. J. Alling]

It's called Bloom, and it's related to the same phenomenon present at 
high contrast transitions on CRT's and the like.

On 1/1/2011 2:18 PM, Bob W wrote:
I can't remember the technical term but I believe it can be dumbed down by
describing it as the pixels bleeding into adjacent ones under some
circumstances.
When I was choosing a dslr for the first time I wanted to use my existing
Carl Zeiss lenses designed for film - some of the best lenses ever made - so
I bought into Olympus and bought an adapter for the lenses. Unfortunately
some of them - some of the very best - suffered so much from purple fringing
that they were effectively useless. So I sold them.

One of the big challenges for the Leica M digitals was to design a sensor
which didn't suffer from this.

B

Yes, purple (and cyan) fringing seems to be native to digital
photography. Can't recall ever seeing it on film. I believe it's a form
of chromatic aberration, but PhotoShop tools designed to correct CA
won't fix it. I generally select it and replace the color to eliminate
it. Some lenses, particularly those designed for 35mm film cameras seem
more prone to it. The new DA and DA* lenses seem to be immune.
Paul

On Jan 1, 2011, at 11:31 AM, willdo-1 wrote:

I'm a little confused about "purple fringing". I have always
understood this to be the result of chromatic aberration from
inadequately corrected optics. From what I read here it seems that some
sensors display the fault more readily than others?
D

Dr E D F Williams
41660 TOIVAKKA
Finland
Ph: +358(0)400706616

On 01/01/2011 18:16, Paul Stenquist wrote:
Thanks Steve. It's good for shooting models with big noses:-). You
know, foreshortening. Of course Gracie has an itty bitty nose.
Paul
On Jan 1, 2011, at 10:51 AM, Steven Desjardins wrote:

What a wonderful picture.  (Now I have to get 400 portrait lens)

On Sat, Jan 1, 2011 at 8:47 AM, Toine<to...@repiuk.nl>   wrote:
Great portrait!

 From other A400 and K5 samples I think I have seen reduced purple
fringing. Did you notice reduced purple fringing on the K5. My
A400 is
very sharp but PF is sometimes hard to control on a K20.

Toine

PS All the best for 2011 to everyone

On 1 January 2011 00:51, paul stenquist<pnstenqu...@comcast.net>
wrote:
When Grace and I were out shooting birds and squirrels at the
nature center, I told her to walk away. When she was about 50 feet
distant, I shot her at f8, 1/1000th, ISO 1600.
No problem blurring the background:-).

http://photo.net/photodb/photo?photo_id=12173039&size=lg
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--
Where's the Kaboom?  There was supposed to be an Earth-shattering Kaboom!

        --Marvin the Martian.


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