Figure 2. From lightweight entry-level up to large pro-level bodies, there’s a digital SLR suited for nearly every budget and need.
Color in Black and White
Color in a digital camera is determined by the filter. Your digital camera is shooting a grayscale image, that is, black and white mixed into shades of gray. Because of the layout of the filter on the sensor, a 6-megapixel camera is actually recording 1.5 million grayscale pixels with a red filter, 1.5 million grayscale pixels with a blue filter, and 3 million grayscale pixels with a green filter. (The human eye is more sensitive to green, so having twice the number of green filters ensures that color fidelity is more accurate.) The photosites have no “knowledge” of color. The software in the camera or the raw converter processes the data and interprets these filtered grayscale pixels to create the missing color data and render a 6-megapixel full-color image.
When the exposure is made, each photosite on the sensor records the amount of light that hits it. This value is the luminance, or intensity of light, and ranges from black (no light) to white (fully saturated). The number of levels of intensity between black and white make up the dynamic range.
The luminance is recorded as red, green, or blue, determined by the color filter at each photosite, and sent to a processor. Four photosites are needed to create the data for one pixel. These pixels are laid out as green, red, green, blue, referred to as GRGB. The conversion method takes this data and interpolates it to make its best guess at the correct color values. |
One differentiating factor is becoming increasingly important: the ability to shoot in the raw format. Point-and-shoot cameras only produce JPEG images, which go through some processing and compression, saving space on the memory card. Images captured in their native raw format more accurately reflect the colors we see through the lens. That’s because digicams producing JPEG files have to convert image data to RGB (red/green/blue, the colors that digital images mix to produce all colors) before it can be processed with an image-editing application on the computer. The conversion process discards data, which can compromise the quality of the image. Raw images, on the other hand, retain all the image data, so the photographer has greater latitude as well as control when editing images.
When you’re ready to make the leap to a digital SLR, it’s time to think about which camera to buy. You’ll find a huge range of options with the digital SLR market, from simple-to-use, compact camera bodies up through pro-level cameras with advanced features (and price tags to match). The first step in your journey is to decide what your budget is and what features are most important to you.
Digital SLR Camera
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March 27th, 2008 at 5:02 am
[...] lennylipton wrote an interesting post today onHere’s a quick excerptWhat makes a camera a digital SLR, anyway? And how is it different than a point-and-shoot camera? If you’re familiar with film cameras, then you know that SLR stands for single lens reflex, a system which uses mirrors and lenses to … [...]
March 28th, 2008 at 1:48 am
[...] you know that SLR stands for single lens reflex, a system which uses mirrors and lenses to … MORE >>Creadit By weight [...]