001 - Jan.28, 2010 --- I’ve Got More Megapixels Than You Do!

     We generally accept that the more megapixels a camera has, the better it’s rated– but what does it mean? One of my kids defined megapixel as a whole lot of little pixies running around drawing pictures -- and maybe that definition isn’t that far off.  With any technical term, there’s always the risk of getting too involved in the definition; while I’m going to risk erring on the simplistic side, even simplistic can sometimes get a little involved, so hang in there with me and here we go.  It’s not hard.

Cameras are often rated in megapixels – literally ‘million pixels’.  A pixel is the smallest element in a digital image that can be processed and is displayed on your monitor in organized rows to display an image. If you look really closely at a television or monitor screen, you’ll see lots of dots (the dots may be round, square or rectangles) – you may need a magnifying glass to see them clearly.  If all the dots are lit up, you should see groups of dots consisting of  a red, a green, and a blue dot. [Illustration 1] A group of one red, one green and one blue dot is needed to display a pixel in all its possible colors.

Let’s take this information and apply it to the camera. As light (the image you’re photographing) comes through the lens of the camera, it’s focused on rows of sensors that record the intensity of Red, Green and Blue (RGB) light striking each sensor. Each group of RGB sensors records the color and intensity for a pixel in the image.

If your camera had a sensor array that was 600 pixels wide and 400 pixels high, your camera would be a 240,000 pixel camera (600 x 400 = 240,000).  This would  translate into approximately a 1/4 megapixel camera – by today’s standards, not very big even for a cell phone camera. A typical consumer level camera these days could easily be 6 megapixels – with a sensor about 25 times larger than in my example. A larger megapixel rating allows the potential for a better picture, especially if the goal is to make a larger print, but the settings on the camera can greatly affect the print quality even on a very expensive 25 megapixel camera.

A digital camera is essentially a small, specialized computer that processes and records light images.  Inside your camera, the intensity of light that strikes each pixel on the sensor is measured for its R, G, and B component value.  When those values are sent to the camera’s computer, the settings on the camera determine how the camera sees these values (the digital image), how it crunches the data into a file, and then how it stores the files -- usually on a removable memory card. These files can then be transferred to another computer for processing, sent to a printer or print service, uploaded to the internet, transferred to a digital picture frame, or even left on the camera and viewed on the LCD screen on the camera back.

I think you’ll find that understanding some of this tech stuff will help you get better and more useable photos, so we’ll gradually explore some of those areas of the camera that we can easily control and put to practical use.  For now, even if you haven’t figured out the mode settings on your camera, turn it on, put in auto mode and have fun taking pictures.
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Tip #1: Practice and get familiar with your camera BEFORE the occasion that you want to get some important pictures happens.  Nothing is much worse than not remembering how to get the camera working when you need it and want that picture. We’ll discuss how camera settings work in future articles.

Tip #2: Fill the frame with the most important part of the picture. Either zoom in with the lens or zoom out and move closer. You’ll get two very different pictures. Try both and see. [Illustration 2]

Tip #3: One of the most common errors is to throw the camera up and click the picture all in one motion.  The computer in the camera needs time to measure the available light, set ISO, lens opening and shutter speed, get a focus point and then record the image - on some cameras, more than ½ a second. Take time to frame the pict, press the exposure button part way down to allow the camera to focus and set the exposure, take a breath and let it partly out, then press the exposure button the rest of the way down. Now you can let the rest of the air out.[Illustration 3]

Tip #4: Most cameras come with a lanyard, wrist or neck strap. Attach them and use them. Wrapping the lanyard around your wrist keeps the camera handy and secure.  And it’s a whole lot better than dropping the camera into the Niagara River.

Next issue, we’ll discuss getting the pictures out of your camera.  See you then.

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