![]() ![]() What difference does it make? The short answer: because of applying white balance, something that is not clipped in RAW may end up being clipped in JPEG. Out-of-camera JPEGs are in one of those gray-balanced working spaces (usually sRGB or Adobe RGB), and that means that white balance is necessarily applied to out-of-camera JPEGs. Since the green channel usually receives the largest exposure (remember that green color cast?), the RAW data in the red and blue channels is multiplied to catch up with the green channel. To get rid of the color cast, we need to equalize (balance) the values of red, green, and blue on neutral subjects, that is to apply per-channel exposure correction to linear RAW data. White balance correction is turned off (UniWB) ![]() Here we switched the white balance correction off, setting UniWB in the white balance drop-down:įigure 3. In a lot of cases, this cast appears as green. Thus we arrive at different exposures for different color channels, producing something one might describe as a color cast. There are two reasons for this imbalance: the responsivities of the red, green, and blue channels of a sensor are not equal*, and the light intensities in the red, green, and blue portions of the light spectrum are also different and vary with the "color of the light." Of course, different intensity of light produces different exposure. For a neutral subject, camera RAW data has non-equal values for red, green, and blue and we say that camera RAW data is not grey-balanced. This is typical for idealized working spaces (sRGB, Adobe RGB, ProPhoto RGB, etc), but hardly ever happens for input device (scanner, camera) data. ![]() You can repeat the simple experiment above yourself, and also check that changing the white balance setting does not affect the in-camera exposure metering readings.įor a subject to appear neutral gray on the screen, it is commonly expected for it to contain equal values for red, green, and blue. An example of "small RAW" with white balance applied is Nikon pre-D850 small RAW format. If, however, the file contains modified RAW data, like with "small RAW" or in multiple exposure mode, white balance may change the RAW data. Thus, white balance is only an instruction for a RAW converter, not an actual modification of RAW data. ![]() The histograms are the same, and adjusting the white balance to the same value on all of the shots results in the same look and color. All RAW histograms remain the sameĪs you can see, changing the white balance setting in the camera doesn't affect the underlaying RAW data in any way. RAW displayed with the same custom white balance applied. The camera takes a light reading of either side of the check card to perform an exposure measurement or white balance and, hey presto, the camera is set optimally for the prevailing light conditions to guarantee perfect shots.Figure 2. The grey side serves as a reference area for exposure metering while the white side enables correct white balance that is so important in digital photography. The flexible check card, made of a special polymer, has an antireflection coating on both sides: one side white, the other grey. Checking always has to beat guessing, and now there’s a perfect check card for exposure metering and white balance. Consider the new ZEBRA check card from the accessory specialist Novoflex. Often quite small things make a big difference to the working life of a photographer. The white side allows calibrating of the white balance of the camera on location to provide accurate colour reproduction. The Novoflex ZEBRA Grey/White Card For Manual White Balance/ Exposure (20 × 15 cm) allows perfect white balance and exposure with the Novoflex Grey and White Card. ![]()
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