Questions about the CHDK with SX40 ? - RAW Shooting and Processing - CHDK Forum

Questions about the CHDK with SX40 ?

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Questions about the CHDK with SX40 ?
« on: 24 / March / 2012, 21:45:49 »
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Hi every one.

I want to request help to anyone who use CHDK, I am proving the sofware and when I take a picture en RAW, I get a pic with the following characteristics:

a. [Photo]: bit.ly/GNST0g


b. [Photo]: bit.ly/GNSWJm


1. It is saw the edge of the lense
2. the image is curve, I mean the lines of the pic is curve like the curve of the lense

Anyone knows why it happens or what I have to do

thanks!

Re: Questions about the CHDK with SX40 ?
« Reply #1 on: 24 / March / 2012, 22:06:07 »
Welcome to CHDK.  When you ask for RAW from CHDK you get exactly what the sensor on your camera records.   You camera firmware normally corrects for these distortions prior to recording them as  JPG.  CHDK RAW gives you exactly what the sensor sees - apparently people think this means better quality as no information is lost in processing in the camera.

Here's a few things you can look at to better understand this :

link> CHDK Wiki Page about RAW
link> CHDK Forum thread on RAW
link> CHDK Wiki Page about Raw Software
link> CHDK Forum Board for RAW
link> How do you fix lens distortion with CHDK RAW files?
link> Decoding CHDK RAW images from a new cameras
link> CHDK Tools : rawconvert.c
Ported :   A1200    SD940   G10    Powershot N    G16

Re: Questions about the CHDK with SX40 ?
« Reply #2 on: 24 / March / 2012, 23:05:32 »
so... it has not solution? then I will always get pictures like that, when I take photos with RAW?

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Offline philmoz

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Re: Questions about the CHDK with SX40 ?
« Reply #3 on: 24 / March / 2012, 23:08:21 »
so... it has not solution? then I will always get pictures like that, when I take photos with RAW?

Yes, at the wide end of the zoom. The amount of distortion drops quickly as you zoom in - compare an image at 28mm to one at 24mm to see this.

Phil.
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)


Re: Questions about the CHDK with SX40 ?
« Reply #4 on: 24 / March / 2012, 23:28:06 »
so... it has not solution? then I will always get pictures like that, when I take photos with RAW?
That is what RAW is - the actual image on the sensor of your camera.  There are two "solutions" :

1) Let the Canon firmware do what it was designed to and convert that information into a JPG image.

2) Process the RAW image on your PC.   Again, the link that I posted previously :

link> How do you fix lens distortion with CHDK RAW files?
Ported :   A1200    SD940   G10    Powershot N    G16

 

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