วันอาทิตย์ที่ 25 มกราคม พ.ศ. 2552

White Balance For Digital SLR Cameras in Plain English

The most common question I am asked is how to properly set white balance on digital cameras. This is a new phenomenon relating to digital cameras and was not an issue with film cameras. In this article I hope to take the mystery out of these settings and to show you how to use this feature to optimize your photographs.

The definition of white balance is:

A camera setting that compensates for the differences in color temperature of the surrounding light. In digital cameras this setting must be adjusted to ensure that all colors in the scene will be represented faithfully. It can be adjusted automatically by the camera or manually, by selecting presets (tungsten, fluorescent, etc.) or by aiming the lens at a totally white surface (the white card) and selecting custom white balance. Source: PC Magazine

A camera will set its color values (red, green and blue) based on its value of white. Changes in color temperature can cause color casts unless a white balance is set. Beginner and amateur photographers can overlook this feature because of their lack of knowledge in evaluating proper color. Building this skill will require some practice. To achieve the best results in correct color you will need to shoot a lot of comparisons so you begin to educate yourself on the differences in cool light vs. warm light and various other types of light.

There are three ways to set white balance in your camera. This is when you will need to have your manual handy.

1) Automatic - AWB on most cameras. This setting will work most of the time but will produce average results. Photographs in the shade will have a slight bluish cast. The bluish cast may look normal to you until you see the difference between a custom white balance vs. a AWB. You may also see color casts from photographs taken indoors with mixed fluorescent and tungsten lighting. Again, once you see the differences in photos using the custom setting vs. AWB you will probably not use this setting anymore.

2) Manual - you can set the white balance manually to suit the respective light source. The following modes are found on most digital SLRs:

• Daylight - sun symbol
• Shade - house casting a shadow symbol
• Cloudy, twilight, sunset - cloud symbol
• Tungsten light - light bulb symbol
• White fluorescent light - fluorescent tube symbol
• Flash - lightning bolt symbol

3) Custom - the symbol is usually two triangles and a dot. This setting lets you manually set your white balance for better accuracy. You will need to check your camera manual to find out the correct steps. In the Canon cameras it is quite simple:

1. Photograph a white object (usually white foam core or a special digital calibration target).
2. Select "custom white balance."
3. Select "set."
4. Select the image captured in step one and select "set"
5. Turn the dial to the custom w.b. symbol.

The custom setting can be very effective, however it can be cumbersome if you are working outdoors in changing light conditions. If you are working in consistent lighting conditions (sun, shade and cloudy bright) I highly recommend it. You will need to test the various methods and see what works for you.

Another option is to select raw (vs. jpeg) where you can set your own w.b. settings in post-production. Stay tuned for an upcoming article on shooting raw in your digital SLR camera.

Mary Buck is a Professional Photographer and Photography Instructor in Duluth, GA. She is author of an E-book and online course , "Take Creative Control of Your SLR Camera." The course is now offered online at: http://www.online-digital-photography-course.com Her website offers free photography tips, reviews of digital SLR cameras and advice on how to start a photography business. Her work can be viewed at http://www.lightscapesphoto.com She owns and operates a portrait studio in Duluth.

ไม่มีความคิดเห็น: