Go Back   Steve's Digicams Forums > Digital Cameras (Point and Shoot) > Olympus

Reply
 
Thread Tools Search this Thread
Old Apr 4, 2003, 8:24 AM   #1
Member
 
Join Date: Feb 2003
Posts: 50
Default C-5050 and purple fringing on indoor lights

Hello,
I tested a C-5050 at a local store (CompUSA) by bringing in my own CF card and taking some indoor pics, then loading them onto my computer. One thing I noticed in some of the shots was what I assume to be the dreaded "purple fringing" around some of the ceiling lights (may gave been fluorescent, but not sure). I saw the purple primarily on my computer screen, but not as much when I printed out an 8x10 matte finish test sample. For simplicity's sake, I had had the camera set to P mode. Are there any changes to settings I could make that would reduce or eliminate the purple fringing in the future?
ruzicka is offline   Reply With Quote
Sponsored Links
Old Apr 4, 2003, 8:41 AM   #2
Junior Member
 
Join Date: Mar 2003
Posts: 28
Default

Hi,

You can reduce it by stopping down the aperture (using a larger F number, say, f/2.8 instead of f/1.8, which is wide open).

Regards,

Steve Price
Steve_Price is offline   Reply With Quote
Old Apr 4, 2003, 10:44 AM   #3
Member
 
Join Date: Jan 2003
Posts: 78
Default Purple Fringes

Hi,

Are you shure about the nature of the problem? It would be helpful to have a look at your pictures. Sometimes you get a blue corona around overexposed areas, more related to limited dynamic range. This is a general problem of digital cameras.

Purple fringing only occurs in the outer parts of your picture. It is clearly detectable by a purple border on one side of an object and a green border on the opposite side. I own a C4000z, which from its tests has a reputation for some purple fringing. Within 4 month of busy taking pictures I never found purple fringes severe enough to be easily noticed. I saw no difference with smaller apertures.

The lens error behind purple fringing is called chromatic abberation, which is a slightly different projection scale (and focal point) for the different colours. Usually GREEN is most affected. Efficient correction of an existing picture is possible with free Photoshop / Paintshop plugin software. If anybody is interested, I shall be back with details.

Regards, Herbert
HerbertRD is offline   Reply With Quote
Old Apr 4, 2003, 11:24 AM   #4
Member
 
Join Date: Jan 2003
Posts: 95
Default Re: C-5050 and purple fringing on indoor lights

Quote:
Originally Posted by ruzicka
Hello,
I tested a C-5050 at a local store (CompUSA) by bringing in my own CF card and taking some indoor pics, then loading them onto my computer. One thing I noticed in some of the shots was what I assume to be the dreaded "purple fringing" around some of the ceiling lights (may gave been fluorescent, but not sure). I saw the purple primarily on my computer screen, but not as much when I printed out an 8x10 matte finish test sample. For simplicity's sake, I had had the camera set to P mode. Are there any changes to settings I could make that would reduce or eliminate the purple fringing in the future?
Well since you were testing out a demo, and so many hands have changed the settings on that camera, I'm assuming that the WB setting might have been changed from AUTO causing the purple fringe you mentioned.

I've tried out the 5050 and it is a superb digicam. I'll take that over the Canon G3.
gmlasam is offline   Reply With Quote
Old Apr 4, 2003, 2:31 PM   #5
Senior Member
 
Join Date: Aug 2002
Posts: 1,910
Default

Purple fringing or chromatic aberration (CA) occurs when you have severe contrast, like dark tree branches against a bright sky, lighting in an arena against the dark ceiling, chrome on a car on a sunny day, etc.

This page shows the cause of CA and how to get rid of it with a photo program:

http://www.dpreview.com/learn/Glossa...rations_01.htm
Mike_PEAT is offline   Reply With Quote
Old Apr 5, 2003, 8:30 AM   #6
Senior Member
 
Join Date: Jun 2002
Posts: 104
Default

I have tested my C4040 in several different ways to isolate the problem. First, it occurs at ANY setting if pointed at bright sunlight. This is easy to avoid. Secondly, it can be avoided by not shooting at the widest setting on the zoom. If you are one of those who MUST have wide angle, this won't work for you. Because of the fringing, as well as the deeeep depth of field, I have completely changed my shooting style from my 35mm SLR days. I was dreaming of the day I could afford a DSLR, but so many user reports of the newer models have indicated some degree of chromatic aberration, and not just from the lens in use, that I have decided to just stick with the C4040. It has paid for itself many times over.
Skiola is offline   Reply With Quote
Old Apr 5, 2003, 4:23 PM   #7
Senior Member
 
Join Date: Aug 2002
Posts: 1,910
Default

Just a quick comment, Oly users get a lot of abuse on CA, but it's not limited to Oly cameras...that link I posted above uses a Canon camera in its the example.
Mike_PEAT is offline   Reply With Quote
Old Apr 9, 2003, 7:37 AM   #8
Member
 
Join Date: Jan 2003
Posts: 78
Default Purple fringing

I just put a post under the thread "Fisheye for the C-4000Z", which contains helpful information with regard to purple fringing.
As opposed to the procedure recommended at the DPREVIEW page, radial shift of the colour GREEN takes care of the cause of the problem.

Regards, Herbert
HerbertRD is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 5:13 AM.