Cameras for Christmas ~ 2008 |
| Finding a camera under the tree, or in your stocking, is a
gift that keeps on giving. Whether you are new to photography, or buying
for a fledgling photographer, there's a camera on this year's list that
will satisfy your requirements with breaking your budget. As might be expected feature sets for consumer models continue to improve, and yet Pixel Madness marches on nearly unabated. I'll get into that qualification after telling you why it's become one of the biggest problems in digital imaging. Digital cameras actually employ analog devices to measure the light source. CCD stands for Charged Coupled Device and it acts as a capacitor for photons, using their energy to produce a scaled voltage. To date only the elusive (for US customers) Canon Powershot SX-1 IS uses a CMOS transistor in place of a CCD, though Sigma makes a DP-1 that houses the Foveon chip. Canon introduced the CMOS and uses that device in all SLRs. The problem with all of these devices is that as they heat up they emit to a lesser or greater degree an interference signal similar to the distortion in audio quality when you are listening to an AM radio station as it's signal fades out. This inference causes noise in images, and displays as blotches which are usually color cast. Combine this with optical distortion and you either print small or expend a lot of effort trying to correct the aberrations and maintain relevant detail. |
Pixel Madness |
| It's Pixel Madness that demands more and more megapixels
like a junkie chasing his first high. This strategy evolved early on
when any increase in resolution was welcome. As the density of CCDs
multiplied so did the noise. The solution came in the form of algorithms
in the camera's internal software program. This is incorporated into the
same routine that produces jpeg images. On some cameras you can save the
RAW data off the chip and process it yourself, but few in the consumer
line allow this choice. To eliminate the artifacts of noise the software cancels the aberrations by blurring the actual image, while the algorithms in the software attempt to discern what is detail and what is noise. In the real world noise suppression compromises the image quality, especially in low-light high ISO settings, but you can also see this in full daylight shots as you'll see in a comparison of two cameras: The Canon G10 and Panasonic's LX3. The result is that despite having almost 50% more pixels the G10 does not produce a better image. The Phil Askey and Crew at DPReview provide the analysis in the G10 “Noise levels and Fine detail in the real world Compared to Panasonic LX3” page. (Link opens in a New Window) So keep in mind that more doesn't necessary mean better, and always compare images by viewing them at 100%. Good reviews always offer than choice, or provide 100% crops of images as part of their review. Now, on to the cameras! |
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