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My DMC-G2 has a viewfinder spec of 1,440,000 dots, but I read a review that says it is really 480,000 pixels:
The electronic viewfinder has an extremely high resolution of 1,440,000 dots (480,000 pixels), offering a 100% field of view and 1.4x magnification. The Panasonic G2's viewfinder has a generous +/-4.0 diopter adjustment range, and a rather tight 17.5mm eye point.
What gives? How am I supposed to compare with other cameras?
I'm a bit skeptical about what they are stating. It says that the viewfinder is "1,440,000 dots equiv". The "equiv" term is an annoying marketing term used when trying to be competitive without stating the true nature of something, they are simply stating it is "equivalent to" such a thing. The Electronic Viewfinder is "equivalent" to a "1,440,000 dot" resolution. Whatever that means, who knows, but I doubt its actually truly 1.4 million dots.
EDIT: Based on the linked review, the EV has 480,000 "pixels" comprised of 1,440,000 "dots". This is a wacky marketing way of saying that it has 480,000 dots each of red, green, and blue, the triplets of which make up a resolution of 480,000 total pixels in a 4:3 form factor. This boils down to a EV screen size of around 1470x1100 pixes.
Comparing the viewfinder with other DSLR's. This viewfinder is 100% coverage and 1.4x magnification. The magnification is multiplied by the sensor size, which is 17.3x13.0mm. Thats a viewfinder size of 24.22x18.2mm, which is basically APS-C size. In contrast, a Canon or Nikon APS-C DSLR will usually have 95-97% coverage and anywhere between 0.70x to 1.0x magnification, depending on the model. Most of the entry-level DSLR's are around 0.85-0.95x, while the Canon 7D is a 100% 1.0x APS-C viewfinder. A Canon 5D Mark II is a 98% 0.71x viewfinder, which is again about the size of an APS-C sensor.
The LCD screen on the back has "460K dots" in it, which these days is pretty low. Most of the more recent Canon and Nikon LCD screens have 920k or 1040k dots.
Actually it is slightly more misleading. 480,000 pixels normally equals 1,440,000 dots but they do get away with only 480,000 actual dots (not pixels) by using something called field-sequential display which is basically 480,000 dots which change colors very fast, sending information for each primary color sequentially.
There are only 480,000 dots but since they send three colors sequentially, it is considered 1,440,000 dot 'equivalent' and therefore equivalent to 480,000 pixels.
Other answers cover everything, but to be blunt: it's marketing bullshit. They are counting each of the three color components of the pixels (red, green, blue) as a "dot". People have been making color displays for decades and only recently has this ridiculousness arisen (for displays, you hear these "dots" called subpixels).
On the other hand, for sensors, each individual photosite - which corresponds to a subpixel or "dot" - is counted as a "pixel" and it's been that way from the beginning of digital cameras. In this case, however, you do get full resolution in the luminosity but only 1/3 resolution in color.
The latter situation causes trouble for the Foveon sensors, where the photosites for the three colors are stacked on top of one another, so you get the same resolution in both luminosity and color. They've responded by quoting the total number of photosites still, but many people believe this is misleading because an N megapixel Foveon sensor gets you only 1/3 of the detail of an N megapixel normal sensor.
To reproduce colour, each pixel needs three dots - one for the red component, one for the green component, and one for the blue component. 480,000 pixels x 3 components gives 1,440,000 dots.
When comparing, make sure you compare figures in the same unit (or even consider cameras with an optical viewfinder, rather than an electronic one)
I think it's worth mentioning that as much as specifying the dot for each color separately seems like "cheating", this is also exactly how the ratings for sensors have been done since day one in digital cameras.
Just for example, a 12 megapixel camera does not have 12 million sites that each sense red, green and blue. Rather, it has (roughly) six million green sensors, 3 million red sensors and 3 million blue sensors, and some sophisticated software to put those together into (to use that magic word, "effectively") ~12 million pixels, each containing red, green and blue information.
In the end, I don't think it makes a whole lot of difference either way -- the actual number doesn't mean much of anything anyway. For the most part, it's a comparative measure so if one says 1.4 million dots and another says 2 million dots (for example) you assume (and hope) that the latter has higher resolution than the former. You only run into a real problem when/if different cameras are rated in different ways, so a particular screen is likely to be called 480,000 pixels on one spec sheet, and 1.44 million on another. Fortunately (?) for us, I'm pretty sure all the current manufacturers "cheat" in exactly the same way, so they're all going to give the same inflated figure for the pixel count, and comparing one to another is pretty straightforward.
