Wednesday 8/8/12: White Balance

"..Why would anyone want to photograph an indisputably colourful world in monochrome? If colour film had been invented first, would anybody even contemplate photographing in black and white?” - Russell Miller , Magnum: Fifty Years at the Front Line of History by Russell Miller , ISBN: 0802116310 , Page: 4

"…the art is in selecting what is worthwhile to take the trouble of photographing…" - Berenice Abbott

Motion is controlled by these factors:

1.     Shutter Speed: 

Faster SS = Less Motion (Frozen)

Slower SS = More Motion (Blurred)

The longer the shutter stays open, the more motion will be shown in the image.  (Even if your subject is moving at a slow rate! – Remember, it’s how much of the image sensor plane is covered during exposure that shows motion.  So, with a shutter speed of 1 second and a person walking you will have just as much motion blur as a person running with a shutter speed of 1/30!).

2.     Focal length of lens:

Short FL (zoomed out) = Less Motion (Frozen)

Longer FL (zoomed in) = More Motion (Blurred)

3.     Subject distance: 

Far Subject = Less Motion (Frozen)

Closer Subject = More Motion (Blurred)

4.     Speed of Object:

Slower Speed = Less Motion (Frozen)

Faster Speed = More Motion (Blurred)

5.     Direction of Motion:

Moving towards lens (into camera) = Less Motion (Frozen)

Moving parallel with lens (across picture) = More Motion (Blurred)

The important factor is how much the image actually moves across the image sensor.  The more of the sensor that your image crosses while the shutter is open, the more the image will be blurred.

 

White Balance and Color Temperature

The color temperature of a light source is measured in degrees Kelvin and it describes its color exactly.  The lower the color temperature, the more “warm” red wavelengths are in the light.  Higher color temperatures have more “cool” blue wavelengths.

Cool = above 5500˚K (like shade at 6000˚K) 

Neutral = 5000-5500˚K (like midday daylight)

Warm = Below 5000˚K (like Tungsten at 3200˚K)    

In a digital camera, white balance is a setting that compensates for the differences in color temperature of the surrounding light. The white balance 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 "lock white balance." Alternatively, a gray card with 18% gray is sometimes used.

White Balance Presets and Color Temperature Scale 

 

Shot with Manual White Balance Settings.  Notice it's the opposite of what you would think - 3000˚K is Cool - It's more like adding a color filter to adjust for the color temperature the camera thinks it is capturing!