It actually comes down to "pixel" size. The smallest unit to record image
data. Colour film can typically record information down to about 60lines
pairs/mm which comes out to 120 "pixels" per mm. The 8mp is really not
relevant. It's the CCD array pixel size. The Canon 20D (an 8 Mp camera) has
a pixel size of 6.5 microns. That equates to 156 "pixels" per mm. The
trouble is, they are not full frame. So you can use more "pixels" with film
to record the same picture. That's where digital are currently behind. The
Canon 20D array is only 62% (1.6X multiplier) of the width of a 35mm frame.
That basically means a equivalent "pixel" size of 97 "pixels" per mm. Still
way off film resolution. Noise is also an issue (as is dynamic range), but
most digital cameras over filter an image. Using a film scanner and a noise
reduction algorithm (as is applied in a digital camera), you can come pretty
close to the same noise floor. When digital goes full frame for non-pro
cameras, then digital will be ahead.

Phil Fairman



"Matt" wrote in message
...
I heard someone say that 8Mp digital cameras were the equivalent to 35mm
film quality?

Does this mean they have the theoretical equivalent resolution? Are they
the equivalent to 35mm?