JCIA, the Japan Camera Industry Association has today officially announced new guidelines for the measurement and marketing of the number of megapixels output by a digital camera. The guidelines recommend the use of effective pixel count. We've known about this for some time, but this is the first time JCIA have made it official. What these new guidelines mean is that from September 1st, 2001 all new Japanese digital cameras must carry a label which states the effective pixel count, not the total CCD pixel count. For example todays '2.1 megapixel' digital cameras would be labelled as '1.9 megapixel'. This is a more accurate, fairer and less confusing method of labelling and should make it easier for the consumer to know what they are buying.

What's still slightly confusing is that JCIA (and the manufacturers) measure effective pixels as the number of pixels captured, this is always slightly higher than the number of pixels recorded because of horizontal and vertical rows used for optical black and those discarded in the bayer interpolation process.

Example: Sony's ICX282 2/3" 5 megapixel CCD (as used in the Minolta DiMAGE 7):

  • Total number of pixels: 5.24 megapixels
  • Number of effective pixels: 5.07 megapixels
  • Number of active pixels: 5.02 megapixels
  • Recommended recording pixels: 4.92 megapixels

Differences:

Labelling today After September 1st, 2001
2.1 megapixels 2.0 megapixels
3.3 megapixels 3.2 megapixels
4.1 megapixels 4.0 megapixels
5.2 megapixels 5.0 megapixels

It will be interesting to note how this effects brands such as Fujifilm with their SuperCCD sensor.