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Enabling CHDK RAW images on the Canon SD780IS

Note: This information is now out of date!

I have written an updated blog post here about the new way to enable RAW DNG support with CHDK.

(This blog post is left here for historic purposes. CHDK now has a Create Badpixel.bin feature in the RAW menu so you no longer need to use the badpixel.lua script method listed below to enable RAW support.)

It is possible to shoot RAW images using the new BETA and older Pre-Alpha versions of CHDK on the SD780IS / IXUS 100 IS.

Here is the basic process to enable RAW support with CHDK on the SD780IS:

Step 1.

On the Beta version of CHDK the badpixel.lua script is located in the CHDK/scripts/test folder.

If you are using the the Pre-Alpha Build of CHDK, download the CHDK script

This file has been modified specifically for use with the Canon SD780IS / IXUS 100 IS camera.

Unzip the archive and copy badpixel.lua into your CHDK scripts folder. Badpixel.lua is a script that makes a map of any bad pixels on the CCD imager. You will have to load and run the script before you can save RAW images.

Step 2.

Turn on ALT mode and load the CHDK Main Menu. The Canon SD780 IS Camera does not have an ALT button so you can simulate the ALT button by quickly tapping the DISP button. The DISP button held for more than 2 seconds acts as the normal DISP button in CHDK.

CHDK Scripting Menu

Open the Scripting Parameters sub-menu.

In the scripting Parameters Menu select Load script from file.

Select the CHDK script

Select BADPIXEL.LUA from the list and press FUNC SET to accept it.

Exit the CHDK Menus.

Step 3.

Switch back to photo mode and then enable the ALT mode.

You MUST be in photo mode for this to work!

When ALT mode is active and you press the shutter button it activates the loaded script and runs it. You have to run this script once before you can then use the DNG RAW image format and save DNG formatted digital negatives.

Press the shutter button to take a photo. It will take quite some time to to take and save the image.

Run the CHDK script

Press the FUNC Set button to save the file. At this point the camera is creating a file called badpixel.bin. This is a map of any bad pixels on the imager. This allows the camera to remove any artifacts caused by bad pixels.

Press the Shutter button to stop the script from running. Turn off ALT mode.

If the file badpixel.bin was not created in the CHDK folder on your SD Memory card you will get an error in Step 4. If this happens, load the SD Memory card on your desktop computer and rename the temporary file bad_tmp.bin to badpixel.bin and continue.

Step 4.

Open the CHDK Menu and then load the RAW Parameters Menu.

Turn on Save Raw.
Turn on RAW file in dir with JPEG

Raw develop:
Set Bad pixel removal to Off
Turn on DNG format
Turn on ‘DNG” file extension

CHDK RAW settings

This will save the Canon CRW raw image in the DNG format. Adobe Photoshop CS4 can now directly open the Canon Powershot SD780IS CHDK RAW DNG files which is quite handy.

SD7080IS Image in Photoshop CS4

SD7080IS Image in Photoshop CS4

You may need a program to convert the DNG file into a format your photo editor can understand such as TIFF or PNG.

You may notice some noise in the RAW images / uncompressed exports. The noise can easily be taken care of by a noise reduction filter such as the “reduce noise” filter. A “median” filter set to 1 pixel could also be used.

Here are a few programs that can convert the DNG formatted images:


Adobe Photoshop CS5


RawTherapee 3.0:


Adobe Photoshop CS5

Graphic Converter

Step 5.

Process the image.

Here is a sample Canon SD780IS Raw DNG image from the CHDK Beta for you to play with:

Canon_SD780IS_sample_RAW_image_new.DNG (18 MB)

Here is an unmodified Canon SD780IS JPEG image taken at the same time to compare against:

Canon_SD780IS_sample_JPEG_image_new.JPG (1.1 MB)

I hope this article helps you get more out of your camera. Good Luck!

  1. I can do everything in this except for when i go to select DNS format I get Error Cannot load CHDK/badpixel.bin please run CHDK/SCRIPTS/TEST/badpixel.lua

    I do see in the main A/CHDK directory there is a file called BAD_TMP.BIN but dunno if that was put there when everything is created.

    RAW files are being created they just are not being saved as a DNG file.

  2. Thanks for doing this tutorial Andrew. I recently heard about CHDK and got all excited about the potential only to encounter the problem of “Cannot Load CHDK/badpixel.bin.” I did a search for that term and was directed here. I now have got RAW to work on my IXUS 100. I notice that the RAW images have a distinct purple tint to them but I am able to remove it pretty easily using software. The DNG pics load fine using iPhoto 09 and Photoshop Elements 8 for Mac.

    Even using the ‘auto’ improvement features of PSE8 I can a great natural looking colour range rather than the artificial ‘Japanese’ colour range of the processed JPEG’s my IXUS usually puts out. Plus I get far superior quality when I compress the shots down to JPEG at similar file sizes to the standard JPEG output.

    I’ll just thank you again for your effort as I’m really impressed with your effort.


  3. i downloaded the raw file (.dng) and couldn’t open it with Adobe Photoshop CS5 or Raw Therapee.

  4. Thx for the quick response. I would really appreciate if you could guide me regarding one thing.
    I am planning to get a new P&S and SD780 and SD940 are available at similar prices at our place. SD940 is a better model in sense it has got a wide angle lens and 4x zoom and got better reviews on web.
    However, I am leaning towards SD780 due to its metallic body, “made in Japan” tag, and fact that it supports CHDK.
    I want to know whether going for 780 based on CHDK compatibility is worth it?


  5. They both would be perfect for an every day point and shoot Canon camera. Both the SD780IS and SD940 can shoot 720p video which is excellent. With CHDK on the SD780IS you can unlock quite a few features and the beta version of CHDK for the SD780IS works pretty well now. I like shooting time-lapses with the SD780IS and CHDK and also use the zoom during video recording feature that CHDK provides.

    It will probably be quite a few months before a working port of CHDK for the SD940 is out.

    What ever camera you decide on I am sure you will be happy with it.

  6. Excellent article! Thanks, Andrew! Now my PowerShot SD1100 is saving into DNG format, which opens directly in Photoshop CS4! Since then the CHDK makes sense!

  7. Very useful tutorial, without this i would be lost in theme.
    Thank you very much!

    Greetings from Hungary!

  8. I’ve got everything working, but i’m getting a jpeg and a dng file. is there a way to turn off the jpeg?

  9. I’ve did the process correctly and all seams to work fine, like dng opening in Lightroom 3 and in Photoshop.
    I only can’t find the way to put the manual exposure on the camera! Is it possible to do it? I only can force the shutter speed going in the menu but can’t change the aperture size…
    It’s also little bit unclear how works the shutter speed overide…

  10. Hi Alessandro.

    The Canon SD780IS does not have an aperture. You can only control exposure using shutter speed and ND filter overrides. I made a new blog post to answer some of your questions about shutter speed overrides.

  11. Hi Andrew,
    i would like to thank you so much!!!
    I spent alot of time in tests and in reading posts on CHDK forum but nothing had been useful.
    Then after few days i found your great blog and at last i fixed my bug: it was impossible to save in raw on my Ixus100; files CRW or CR2 (i can’t say images) were blank/with no pixels and at the same time i wasn’t able to run badpixel script until i modified bad_temp.bin in badpixel.bin as you suggest.
    I could post this story on CHDKforum if you agree, since i wrote my request there with no solution, and yours can help other people.
    I will be glad to come back to your site to learn more…
    Many congrats and greetings!
    Leo – Italy

  12. andrew, iam using alpha(or pre-beta) version of chdk for ixus95is/sd1200is and followed ur tutorial step by step and everything is working fine for me.

    the in-camera chdk developed dng files open in ps cs5!!! thanks so much:)

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