Montag, 26. April 2010

Stop the megapixel madness

The specs for Nokia's new flagship Symbian^3 smartphone just leaked out (see, thanks for the photos). If these are correct, it will have a 12 megapixel camera. The new flagship must have the highest spec components available, right?
But unfortunately, the camera phone makers and buyers have not learned the lesson, which the compact camera folks just have.
But it is so easy:
  • On a given sensor size, more megapixel means smaller pixel
  • Smaller pixel mean less light sensitive pixel
  • Less light sensitive pixel mean more noise
This is just simple physics. As well as
  • It does not make sense to build a camera with a higher sensor resolution than supported by the optics
This is known to every amateur photograph, but not to every average more-is-always-better buyer. Thus, ambitioned amateur photographs typically buy compact cameras with lower resoltution than the average buyer. And the manufacturers react to it. Panasonic's high end compact camera, the LX3 has the lowest resoltion of all Panasonic compact cameras. And it has the best image quality.
It is getting weird when looking at Canon's latest product lineup. While the entry level compact cameras like the new SX210 getting up from 12 to 14megapixel, their high end compact cameras G11 and S90 are downgraded from 14,7 to 10 megapixel.
Unnecessary to mention, that the SX210 produces noisier images than its 12 megapixel predecessor SX200, whereas the G11 produces much better images than its predecessor under lowlight conditions.
And to compare this to camera phones: even the sensor of Nokia N86, which is the largest sensor of all camera phones, is smaller than the sensor of the cheapest compact cameras. So if 9-10 megapixel is a reasonable resolution for high end compact cameras with the largest sensors in this space, this would mean that the resoltion of camera phones has to be below this margin. Even 8mp should be too much, maybe 5mp would be a reasonable resolution.

This is a lesson, camera phone producers and buyers still have to learn. And one already learned. The Apple iPhone has a 3.2mp camera, the next generation will probably have 5mp. And the iPhone's photos are better than these from most camera phone, exept some photo experts like the N95 or N86.
So hopefully other manufacturers will follow and downgrade their camera resolution for better image quality.


Arrgh! This posting is just one day old and Nokia proved me to be wrong ... at least to some degree. Today, the Nokia N8 has officially been announced and they showed some sample photos on Nokia Conversations. These are quite good, much better than I expected.
In fact, this is no magic. In another posting, they explained the trick: they took "the biggest sensor in a mobile device". The N86 had a 1/2,5'' sensor, which has been the standard for cheap compact cameras some years ago. Now, the compact camera standard is 1/2,33'' and many of these are available with 12mp. So probably the N8 has just gotten a standard compact camera sensor. And with a given aperture speed of f/2,8, it will give the N8 a reasonable low light performance, comparable to standard compact cameras.
I can't wait to see N8 tests from photographic sites. Probably, the little optics won't keep up with the 12mp sensor, so I am curious what the effective resolution of the N8 will be.
But in fact: if these photos are not faked, the N8 will probably become the best camera phone on the market.

According to, the sensor is even larger than I assumed. If this is correct, it is a 1/1.83" sensor. To put this into comparison with compact cameras: only a handfull of high end compact cameras have a similar sized sensor, eg. the Canon G11, Panasonic LX3 or Fuji F200EXR.
Back to my initial statement of stopping the megapixel madness: if Nokia had restricted the resolution to 8-10mp, the photos would probably be even better. But the N8 will probably not only make better photos than all other camera phones, but also will successfully compete with digital compact cameras.

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