Go Back   Steve's Digicams Forums > Digicam Help > General Discussion

Reply
 
Thread Tools Search this Thread
Old Oct 29, 2006, 7:06 PM   #1
Senior Member
 
Join Date: Aug 2006
Posts: 268
Default

Is there some design characteristic responsible for the purple fringing? Does this also occur on the S6000FD and F31FD?
Contriver is offline   Reply With Quote
Sponsored Links
Old Oct 29, 2006, 7:26 PM   #2
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Virtually any digital camera can exhibit a bit of Purple Fringing in the right conditions. I could probably find a photo exhibiting it from any popular digital camera, just by looking through some of the online photo albums at popular photo sharing sites.

I've seen the causes of it debated for years. Lens quality is a factor.

The microlenses being used on the sensors (each photosite has a tiny microlens over it to help amplify the light) can also help to cause it. I can remember seeing some information from Kodak engineers about 5 or 6 years ago contributing some of it to the microlenses being used (because of diffraction as the light hits them).

You can also get some CCD blooming contributing to it (where you get some charge overflow between adjacent photosites in overexposed areas).

You tend to see it at high contrast edges (for example, tree limbs and leaves against a white sky), or a white shirt against a darker background.

Out of focus areas can be more prone to it (for example, when you're focusing on a closer subject with out of focus trees in the background against a bright sky).

Stopping down the aperture (smaller aperture/higher f/stop number) can help with some lens designs. Some focal lengths may be worse than others, depending on a lens design.

But, you can see it in some conditions with very good lenses.

Steve had this to say about the F30:

Quote:
The FUJINON 3x optical zoom offers a typical range for a consumer model. At its 36mm wide angle extreme, it provides a field of view sufficient enough for most interior and landscape shots, while it's 108mm maximum telephoto focal length is effective both for portraits and to bring your distant subjects a bit closer. Overall it helps the F30 produce nice sharp images, with small traces of chromatic aberrations (purple fringing) around highlights as well as moderate barrel distortion at wide angle, but virtually no pincushioning at the telephoto end.


F30 Review Conclusion


JimC is offline   Reply With Quote
Old Oct 30, 2006, 7:34 AM   #3
Senior Member
 
Join Date: Aug 2006
Posts: 268
Default

Is the F30 considerably worse with purple fringing than other small P&S cameras?
Contriver is offline   Reply With Quote
Old Oct 30, 2006, 8:51 AM   #4
Senior Member
 
BenjaminXYZ's Avatar
 
Join Date: Jul 2006
Posts: 788
Default

I think Fujifilm cameras have rather poor lens quality, but superior CCD(s).

Panasonic is just the COMPLETE opposite.
BenjaminXYZ is offline   Reply With Quote
Old Oct 30, 2006, 9:04 AM   #5
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Quote:
Is the F30 considerably worse with purple fringing than other small P&S cameras?
I don't have this camera, and the only way to tell how it compares with a specific model would be to take photos of the same subjects at the same time, using similar settings.

But, from what I can see looking at samples from it, absolutely not.

In fact, I'm pretty impressed with the lack of Purple Fringing in areas you'd normally expect to find it in some of the images.

I can find a touch of it in the corners in one or two of our samples. But, a touch of corner softness is common in many lenses, and that's probably the reason I'm seeing it there in some.

I haven't looked at a lot of images from it to see if it may be more prone to it at certain focal lengths and aperture settings. Have you got this camera? You seem to be pretty concerned with it.

Any camera design is a compromise in one area or another. You can't expect the performance of a high end, dedicated prime (non-zoom) lens at all focal lengths from a zoom lens camera that fits in your pocket. ;-)

Some of the image editors even have dedicated features to remove purple fringing now. It's a common issue. In fact, the thread at the top of the threads list in one of our forums right now is on how to deal with this issue:

http://www.stevesforums.com/forums/v...mp;forum_id=78

At typical print sizes, you're probalby not going to notice it, even it you do have a touch, and if you plan on a very large print from an image, you'd probably want to spend some time preparing it better for printing anyway in an editor.

There is some evidence to suggest that some manufacturers are starting to look for PF in the image processing pipeline to try and remove it there.

Ironically, some of the first models I've seen this discussed about was some of the Panasonic models (since Benjamin mentioned them).

No camera is perfect.

JimC is offline   Reply With Quote
Old Oct 30, 2006, 9:43 AM   #6
Senior Member
 
Join Date: Aug 2006
Posts: 268
Default

I understand that no P&S is perfect. I am just trying to learn what to expect in a P&S. What strengths andlimitations exist and so on. I hear alot about this 'purple fringing'. I was thinking that maybe it is the side effect of a specific feature/design. So, if it was due to one particular thing, I was hoping to learn what that thing was so that I can take that into consideration when researching a camera.

BTW, do an dSLRs suffer from purple fringing?
Contriver is offline   Reply With Quote
Old Oct 30, 2006, 9:57 AM   #7
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

You bet that a dSLR also suffers from it. Some lenses are worse than others. But, it's a common issue, especially at larger apertures (smaller f/stop numbers).


JimC is offline   Reply With Quote
Old Oct 30, 2006, 10:31 AM   #8
Moderator
 
Join Date: Aug 2004
Posts: 8,529
Default

Contriver wrote:
Quote:
BTW, do an dSLRs suffer from purple fringing?
Yep, I have a $2200 lens I use for sports shooting that has the problem :evilexacerbated by shooting it at 2.8 all the time - as Jim indicated the wider apertures make the problem more noticable).


JohnG is offline   Reply With Quote
Old Oct 30, 2006, 1:14 PM   #9
Senior Member
 
Join Date: Aug 2006
Posts: 822
Default

Here's an example of where you'll get purple fringing. Focusing close, with a bright sky in the background, and branches against the sky:


Attached Images
 
kenbalbari is offline   Reply With Quote
Old Oct 30, 2006, 1:23 PM   #10
Senior Member
 
Join Date: Aug 2006
Posts: 822
Default

Normally it occurs when the sky gets overexposed. The above is an extreme closeup where I got it and still had a blue sky. More typically, it will happen when you are shooting an object in the shade, with a bright sky in the background. In this next shot, a cloud had covered the sun, muting my sunlight, but the sky behind was still being lit by the direct sun:


Attached Images
 
kenbalbari 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 7:59 PM.