The fallacy of megapixel - megapixels camera
Internet Giant Social Media - The fallacy of megapixels
You can start to see that cramming more pixels onto a sensor may not be the best way to increase pixel resolution.
Jon Erensen, a Gartner analyst who has covered camera sensors, remembers when the cell phone industry jumped from 1-megapixel to 2-megapixel sensors.
"They would make the pixel sizes smaller [to fit in more pixels]," Erensen told me over the phone, "But keep the image sensor the same." Erensen similarly used the water analogy, this time swapping "buckets" for "wells."
What ended up happening is that the light would go into the well and hit the photo-sensitive part of the image sensor capturing the light. So if you make the wells smaller, the light has a harder time getting to the photo-sensitive part of the sensor. In the end, increased resolution wasn't worth very much. Noise increased.
The relationship between the number of pixels and the physical size of the sensor is why some 5-megapixel cameras can outperform some 8-megapixel cameras, and why we may not see, or want, a 12-megapixel camera on a smartphone. A slim smartphone limits the sensor size for one, and moving up the megapixel ladder without increasing the sensor size can unnecessarily degrade the photo quality by letting in less light than you could get with slightly fewer megapixels.
Then again, drastically shrunken pixel sizes aren't always the case when you increase your megapixels. HTC's Bjorn Kilburn, vice president of portfolio strategy, did share that the pixel size on the 16-megapixel Titan II measures 1.12 microns whereas it measures 1.4 microns on the One X's 8-megapixel camera. CNET's Josh Goldman points out that this is a small pixel size; however the take-away in terms of this discussion is that the two similar sizes mean that photo quality should be comparable at a pixel-by-pixel comparison.
Unfortunately, most smartphone-makers don't share granular detail about their camera components and sensor size, so until we test them, the quality is largely up in the air. Even if smartphone makers did release the details, I'm not sure how scrutable those specs would be to the majority of smartphone shoppers.
For more information on the interplay between megapixels and sensors, check out the excellent description in CNET's digital camera buying guide.
What about Nokia's 41-megapixel PureView?
Nokia's story behind its 808 PureView smartphone is really interesting. CNET Senior Editor Josh Goldman has written one of the best explanations of the Nokia 808 Pureview's 41-megapixel camera that I've seen. I strongly suggest you read it.
In the meantime, here's a short summary of what's going on.
Juha Alakarhu (pronounce his first name YOO-hah), is head of camera technologies at Nokia, where he works within the Smart Devices team. Alakarhu explained to me that although Nokia has engineered the PureView to capture up to 41-megapixels, most users will view photos as the 5-megapixels default.
