So, with the new iPhone 4 rolling out at WWDC, there has been a lot of talk about this particular device and all of the "features" that it is packing. I just posted a lengthy (Google) Buzz report on the iPhone and what I thought about these so-called features. But what Steve Jobs obviously did was offer a lot of fodder for the Apple fanbois to boast about the next time you're enjoying a cup of coffee at Starbucks with your Apple toting friends. Words like Backside Illuminated sensor, A4 chip (which incidentally has an unknown clock speed; Jobs conveniently left that bit of information out), and of course, "retina display." Retina display is one of the more obvious marketing terms rolling out of the iPhone unveiling. It was comical that this unveiling had so very little buzz (thanks to Gizmodo and Vietnam) and with all the technical issues, you would think you're watching Google unveil GoogleTV at their I/O event. But it was also comical listening to Jobs explain "Retina Display," for a number of reasons: 1) The 10-12" distance is completely arbitrary. It's obviously the distance that most people hold their phones from their face. 2) The effective resolution of the retina is 250 dpi, depending on day or night conditions, etc. 3) Here are the actual dpi to distance relationships: @24"= ~100dpi, @18" = ~135dpi, @12" = 200dpi, @8" = 300 dpi. Now, if you don't know how far 8" is from your face, it's basically nose to the screen. So effectively, since the retina can only effectively resolve 250dpi natively, the display dpi only needs to be 200dpi for clear, smooth images. 4) Incidentally, dpi (and for that matter, ppi; Jobs uses them interchangeably) are different standards of resolution than screen resolution measure (e.g. 800x480, 960x640, etc.) But dpi and image resolution are not the same thing. A 960x640, 3.5" resolution screen amounts to something like 200K pixels in a square inch. So, technically speaking, you can "output" a 300dpi image on a screen that's "less" resolute. With that said, the Motorola Droid has an image resolution of 854x480 (as we all well know) and outputs at a pixel density of 267 dpi/ppi. The Droid Incredible has a "perceived" image resolution of 800x480 (although the PenTile pixel structure effectively displays 533 x 480) and outputs at a pixel density of 252 dpi/ppi. Both of which, exceed the 200 dpi at Steve Jobs' arbitrary 10-12" distance, making the DROID (and HTC Android phones with OLED)... RETINA DISPLAYS!