CHDK

Today on one of the flashlight discussion areas, a guy had taken some macro photos of a flashlight he had taken apart. Someone said that if he used a Canon camera, he should use CHDK, which allows you to create RAW images and add a lot of features to your camera. Well, I have a Canon camera. And one of the things I would really like for it to do when I’m taking pictures of flashlight beams (shining them on a wall to see what tint, brightness, and beam pattern you get) is to turn off the automatic white balancing that the camera does. If I have a flashlight with a cool white, bluish beam, the camera will reduce the blue color and make it look more white. If the flashlight has a warmer, more orange, tint, the camera changes it to make it more white. So I end up with two pictures that look the same even though the tints are very different. I can shine both lights at the wall, which helps some, but often the camera will exaggerate the differences, especially if the tints are fairly close. So I’d like to be able to turn that off, but the only way I can figure to do that is some process where you take a picture of something that is totally white in order to set your own white balance. And I don’t know if that is stored or if you have to do that every time you want to take a picture.


So I went the CHDK website, here. CHDK stands for Canon Hack Development Kit. These guys have developed this hack into the operating system that a Canon camera uses to offer these additional features. The program runs from the SD memory card that you put in the camera and it doesn’t permanently change anything in the camera, it only runs when you turn the camera on and there is a memory card with this software on it. That’s a pretty neat concept right there.

So I had to try it out. I downloaded a bunch of stuff. They try to make it easy, but at the same time they also seem to make everything harder to understand. For instance, it seems like you should just be able to put the files on the memory card, but instead they wrote another program that you run on your computer and it writes the files to your memory card.

I’m still having some trouble figuring out what is going on. The RAW files are just a dump of data from the camera eye, not compressed into jpeg format and not given any kind of processing apparently. So they don’t look like much, if you can see them, which I can’t, because I don’t have any software that reads RAW files (yet). Then you use Photoshop or some kind of image software to balance everything the way you want. I’m not sure that even a RAW files isn’t already white balanced, so this may not work at all for what I want.

One neat thing this software can do is take multiple images of the same thing with a variety of different settings on the camera. For instance, it could focus up close, a little further out, and in the distance. Then some other software (not sure what) takes the 3 pictures and gets only the parts of each that are in focus and now you have a picture that is totally in focus, whether stuff is up close or farther away. You can do the same thing with light levels, so that things in the shadows are adjusted separately from things that are in direct sunlight and get the best lighting for everything in the picture (supposedly).

A lot to learn and play around with . . .

One thought on “CHDK

Leave a Reply

Your email address will not be published. Required fields are marked *