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-   -   CA, or color fringing/separation (https://www.dvinfo.net/forum/canon-xh-series-hdv-camcorders/84840-ca-color-fringing-separation.html)

Piotr Wozniacki January 26th, 2007 04:47 AM

CA, or color fringing/separation
 
We all saw signs of bad lens performance several weeks ago, with Kaku Ito's first clips; one of them showed a tree on the left scene extremity with bad color separation on its branches. Now, I can see this phenomenon even closer to the picture's center, especially when there is some regular bright area (ie, a rectangular peice of white paper) - the left vertical edge shows some purple, and the right vertical edge - some greennish (or blue, cannot remember now) colors along it. Again: is it just my unit, or is it standard?

Michael Mann January 26th, 2007 06:25 AM

I presume it is standard, more or less. My unit shows quite noticable fringing as well.

Stephen Cannon January 26th, 2007 10:57 AM

CA is a problem particularly If you are shooting wide angle and with a wide open iris. Stopping down will help and may entirely eliminate the CA.

Stephen Cannon

Alex Leith January 26th, 2007 11:35 AM

There does seem to be a bit of variation in the lenses. Some show very little fringing, and some show more.

Generally the fringing in these lenses is quite noticable. It's on a par with the V1 - but for some reason it doesn't hit you quite so much.

Generally the greater the range of the lens, the more CA it shows.

Jim Hardy January 26th, 2007 11:42 AM

There are some pretty good software fixes for CA/fringing in digital still photos.

What about video?

Are there any workarounds or plugins etc. for FCP/Vegas/PP so this can be fixed in post?

Alex Leith January 26th, 2007 11:49 AM

Fixing CA in video is more challenging especially if you're zooming in vision - which of course we all know not to do (but do it anyway).

I haven't tried either of them but:

River Rock Studios make a cheap plugin that can simulate (or fix) CA for Final Cut Pro. http://www.riverrockstudios.com/rive...cheapLens.html

Digital Film Tools also make a slightly more expensive plugin set for FCP that includes CA fixing. http://www.digitalfilmtools.com/55mm...aberration.htm

Piotr Wozniacki January 26th, 2007 12:45 PM

Quote:

Originally Posted by Alex Leith
Generally the fringing in these lenses is quite noticable. It's on a par with the V1 - but for some reason it doesn't hit you quite so much.

Generally the greater the range of the lens, the more CA it shows.

So generally, it's less pronounced than with the V1? And how does the A1 compare to the Z1 in this respect?

Alex Leith January 26th, 2007 05:44 PM

Quote:

Originally Posted by Piotr Wozniacki
So generally, it's less pronounced than with the V1? And how does the A1 compare to the Z1 in this respect?

Actually I meant the other way around. The V1 actually shows worse CA (in my opinion)... but it doesn't seem to jump out at you quite as much (if that makes sense).

When they're there the red/green outlines are really noticable with the A1... but I have to say that they're a relatively rare addition to most images.

The A1 has less colour fringing than the H1, but more than the Z1. Of course the Z1 only has a 12x zoom, so fringing is likely to be less. The HVX200 is the nicest looking lens of this price range of cameras.

You can minimize CA, by avoiding high contrast edges; using the middle of the zoom range; and keeping to medium F stops. Even very expensive lenses show fringing


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