Re: new camera 41megapixels in a phone

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From: PhotoRoy6@xxxxxxx
: Re: new camera 41megapixels in a phone


_http://forwardthinking.pcmag.com/show-reports/294650-how-nokia-s-41-megapix
el-smartphone-works_
(http://forwardthinking.pcmag.com/show-reports/294650-how-nokia-s-41-megapixel-smartphone-works)



wow indeed! but I have to crawl the numbers, forgive me.. I'm used to surprise and derision directed at claims of high quality phone cams, having bought and owned a 5Mp phone cam back in the days when 1.5Mp was the biggest you could get in the Western market from Sony/Nokia/Others .. and I'm more than used to scepticism at high quality images from phones. However some of this just sounds odd to me and it wouldn't be the first time a manufacturer obfuscated things to their advantage (I'd add that my phone cam used a Sony digital camera sensor as opposed to the sensors designed for phones - and it had a mechanical lens cover rather than a nasty chunk of glass in front of the lens to protect it/degrade the image.. )


http://www.pcmag.com/article2/0,2817,2400773,00.asp

http://tinyurl.com/87n9h4u has some pretty crazy sounding explanations of things..

"e.g. If a conventional digital camera set to ISO 100 uses a shutter speed of 1/30th second,
the Nokia 808 PureView uses 1/180th second in the same lighting conditions."

and

"Less is more.
The simple structure of Nokia PureView Pro beats more complicated designs hands down. ... Conventional designs need many more lens elements to provide the zoom capability and correct aberrations, but these interfere with definition and/or light transmission. Our simple structure has enabled a significant improvement in manufacturing precision, and our lenses are produced with 10x greater precision than SLR lenses." (but they still put a chunk of ordinary glass in fron tof the lens to protect it :(


nice to see a manufacturer include this little fact though (well, the last bit about the nyquist theory :) "oversampling eliminates Bayer pattern problems. For example, conventional 8MPix sensors include only 4Mpix green, 2Mpix red and 2Mpix blue pixels, which are interpolated to 8Mpix R, G, B image. With pixel oversampling, all pixels become true R, G, and B pixels. What's more, based on Nyqvist theorem, you actually need oversampling for good performance. For example, audio needs to be sampled at 44 kHz
to get good 22 kHz quality."

now the numbers from Nokia

the claimed specifications:
Carl Zeiss Optics
Focal length: 8.02mm
35mm equivalent focal length: 26mm, 16:9 |
28mm, 4:3
F-number: f/2.4
Focus range: 15cm - Infinity (throughout the zoom range)
Construction:
· 5 elements, 1 group.All lens surfaces are aspherical
· One high-index, low-dispersion glass mould lens
· Mechanical shutter with neutral density filter
. Optical format: 1/1.2"
. Total number of pixels: 7728 x 5368
. Pixel Size: 1.4 microns

they also go on to say "For example, with the default setting of 5Mpix (3072 x 1728), once the area of the sensor reaches 3072 x 1728, you've hit the zoom limit. This means the zoom is always true to the image you want." - uh huh..

This is a small sensor, but not as small as many other phones use - that's nice :)

they claim a 41Mp image from 7728 x 5269 pixels, but then they talk of a limit of 3072x1728 pixels..

It uses a digital zoom.

te sensor is about 10mm x 12mm based on my calculations

Then I find:
http://www.phonearena.com/news/Just-how-big-is-the-sensor-on-the-Nokia-808-PureView_id27515
which shows the actual sensor - which certainly is small

and
http://www.dpreview.com/news/2012/02/27/Nokia-808-PureView-with-41MP-sensor
which is basically a rehash of the manufacturers blurb.

I'd like to know a lot more about this sensor. the example images look quite good tho





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