Canon Hacker's Development Kit

The RAW format produced by the CHDK has some restrictions. First, CHDK’s RAW images are not equipped with EXIF data. Second, the RAW format produced by the CHDK is not understood by all RAW converters. Some simply refuse to open the image. A good choice is the program RawTherapee, which is available for the main [...]

Bad Pixel Removal works quite differently and only in connection with DNG. A bad pixel map is created in advance. In section 4.5.2, we already discussed how such a map is created. When running, the script badpixel.lua grabs a bad pixel map from the camera (normally used for the creation of JPEG images) and stores [...]

Dark Frame Subtraction is a common technique for removing unwanted artifacts from an image. When an image is taken, the camera will make two exposures: one with an open lens, the other with a darkened lens. The second exposure will only show noise and hot pixels. Subtracting the second image from the first will remove [...]

RAW images are nothing more than the unmodified sensor data produced by the camera. JPEG images, in contrast, are the result of a development process: the color temperature is estimated and applied, the image is sharpened, noise is removed, and the contrast is compressed. Scenes with stark contrast usually have some highlights clipped. So, the [...]

The focal system of Canon compact cameras is dominantly based on an autofocus system. Only some cameras in the higher price range allow manual focusing. The autofocus system is augmented by special focus modes such as Macro or Infinity, which can be set manually. Over the years, the focus system has become more and more [...]

Custom Curves are another option in the CHDK to control the outcome of a shot. Curves are applied after an image has been taken; they don’t influence exposure settings such as aperture or sensor speed. They simply modify the digital data delivered by the sensor before it’s packed into a JPEG file. This can make [...]

Most Canon compact cameras have rather limited flash functionality. My SD1100, for example, supports the following modes: Automatic, Off, and On (in manual mode). Red-eye correction and a red-eye lamp can be switched on, and in manual mode there is a Slow Sync option. However, there is no way to control the flash power. This [...]

In the past, night photography has not been easy with digital cameras. At high ISO values, the noise in the image goes up. Shooting at low ISO values is not always possible — lack of a tripod may be just one reason. And at long exposure times, the camera’s sensor tends to produce artifacts: hot [...]

One amazing feature of the CHDK is the provision for ultra-short shutter speeds. Before we go into the details, let’s take a look at general shutter technology. Traditional cameras from the analog era use mainly two types of shutters. One is the focal plane shutter, which is also used in DSLRs. Here, two curtains move [...]

Another convenient way to control exposure is the Zebra feature. While the histogram informs you about the tonal range of the complete image, the Zebra feature identifies image areas that are under- or overexposed. These areas are displayed with a pattern overlaid on the image to make them stand out visually. When enabled in the [...]

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