Magenta edge tinging at high ISO and a possible solution...

Started Aug 17, 2009 | Discussions thread
GordonBGood Veteran Member • Posts: 6,308
Re: PROGRESS: Version has one more tiny fix...

photogerald wrote:

Thanks for your efforts, Gordon!

Thanks for the encouragement, I was wondering if anyone other than Dominique (dlacoutu) was actually following this.

I've generally avoided shooting at high ISO (1600 and up) with my K20D, but with your tool I might be more inclined to do so.

I'm glad you feel so inclined to try high ISO, but perhaps it's time to list a few things that this program does not do , as follows:

1) It doesn't do anything about the existing levels of noise at high ISO, which will still be seen at 100% zooms in the deep shadows unless you use extra external Noise Reduction and likely down sampling of the images (or smaller prints) in order to compensate for the loss of resolution in doing NR.

2) It doesn't do anything about noise patterns by column and row, other than if I am able to compensate for certain wide vertical banding patterns in a future version (but I am not promising).

3) It doesn't do anything about the actual black level not being absolutely black and in fact makes the center of the image less black while making the top and bottom (landscape orientation) slightly more black. Note that overall black level can easily be corrected with most raw converter applications or in post process editing.

All that it does is reduce the amount of top and bottom border colour tingeing, usually magenta, while not affecting the overall colour balance (as far as I know). If this was the main thing preventing you from using high ISO's with your K20D, have at it. Remember that ISO 6400 in this camera is more or less equivalent to shooting at ISO 800 to 1600 with most compact cameras as to image quality once you reduce the noise as much as they do, so you aren't going to produce wonderful image quality when viewed at large zooms from full size images.

To all, I have almost completed the support for PEF format raw files, which will be released with version

Regards, GordonBGood

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