A lens profile for the SX40HS, where? - SX40HS lens correction opcode in the DNG - General Discussion and Assistance - CHDK Forum supplierdeeply

A lens profile for the SX40HS, where? - SX40HS lens correction opcode in the DNG

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Offline dvip

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Any idea if a chdk DNG has opcodes for lens correction?
I need a lens profile for the SX40HS.
Yes, I know one can be created with Adobe tools but I was wondering if
there is a place where I can download one for the SX40HS or the A590IS? 
Thanks :xmas


Offline philmoz

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The DNG spec allows for lens correction opcodes.

I played with this on the G1X by converting native raw files to DNG with the Adobe convertor then extracting the lens correction opcodes from this DNG file and getting CHDK to insert the opcode in it's saved DNG file.

It didn't work very well - although the image distortion was corrected it messed up the bayer de-mosaicing and created very strange color artefacts. I don't think the lens correction opcodes were designed to work with camera RAW image data (as opposed to the converted RAW data in the DNG file created with the Adobe convertor).

The only real option at the moment is to create profiles with the Adobe tools.
There are some SX40 profiles at http://photography-on-the.net/forum/showthread.php?t=1188185

CHDK ports:
  sx30is (1.00c, 1.00h, 1.00l, 1.00n & 1.00p)
  g12 (1.00c, 1.00e, 1.00f & 1.00g)
  sx130is (1.01d & 1.01f)
  ixus310hs (1.00a & 1.01a)
  sx40hs (1.00d, 1.00g & 1.00i)
  g1x (1.00e, 1.00f & 1.00g)
  g5x (1.00c, 1.01a, 1.01b)
  g7x2 (1.01a, 1.01b, 1.10b)


Offline dvip

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I'll try the lcp file they have there:  Canon PowerShot SX40 HS -4.3-150.5 mm f2.7-5.8- v2.0 - RAW.lcp
I need it so I can use it with RawTherapee. I hope it works. Thanks.

« Last Edit: 15 / December / 2012, 19:19:21 by dvip »


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