In the consumer market, which Dalsa does not target, 5-megapixel cameras often use the same size CCD as a 3-megapixel camera. More pixels are simply crammed onto the same-size chip.
"The pixels themselves get smaller," Myles said. "This has an impact on image quality."
Why? For one thing, smaller pixels are less light-sensitive.
Also, the lens quality might not support the additional pixels. As the receptors get smaller, a higher quality lens is needed to properly focus light onto each pixel. So where each pixel ought to capture different light information -- say perhaps a subtle shading change on the subject's cheek -- the same information can get spread across several pixels after passing through a lower quality lens.
This makes me worry even more about manufacturers who cram more pixels onto the same size sensor. Sony's crammed 8mp on their new F828, without enlarging the chip. No one questions that it makes a lot of noise over 100 ISO. And Baldy revealed that Canon's 10D will upgrade to 8mp from 6. Unless they increase the sensor size, will it all be for naught?
No question you know more about it than I do. Is there unused space on the current 10D imager? If not, then what you say makes sense. But it the 10D imager is full, then won't adding more pixels force them to make each pixel smaller, a la article?
Yes the pixels will get smaller but they will still be large enough. Think
about Canon's 11MP 1Ds
The 10D imager is [font=Arial, Helvetica, sans-serif]22.7mm x 15.1mm[/font] compared to the F828 [font=Arial, Helvetica, sans-serif] 2/3" (whatever
that means) Thus the 10D has the area for 8MP. [/font]
Sony's sensor is 8.8x6.6mm.