Tuesday, October 27, 2009

Cypress Full Frame CMOS Sensor is to be Used in the Rumoured Upcoming Pentax Full Frame Body?

With surprise and to doubt about the reason(s) behind, Cypress has updated their datasheet of their 36 x 24mm CMOS sensor at their website, recently:-

http://download.cypress.com.edgesuite.net/design_resources/datasheets/contents/ibis4_14000_8.pdf

And, a rumour has begun recently for that the "upcoming" Pentax Full Frame DSLR body will use this sensor:-

http://www.nphoto.net/news/2009-10/22/6f1e08121de985fa.shtml
(Text in Simplified Chinese)

..of which the contents are 90% the same as another Chinese article that was posted two years ago at another Chinese site:-

http://news.fengniao.com/69/691199.html
(Text in Simplified Chinese)

But just don't look down at those Chinese websites' reports. My experiences were that they were either pure rumours and imaginations or the cases were just in another extreme - the authors received REAL information from insiders and they dared much to disclose, without anything of being afraid! :-)

As for the Cypress sensor, below are some of my impressions on the published Specs:-

1. 8um Pixel Size is really large. The K-x pixel size is only 5.6um, as I have calculated last time;

2. The "Rolling Shutter" capability means that it should be video recording ready, and also the Live View (For more technical information about the "rolling shutter", read my last post here);

3. The Master Clock is of 15MHz is slow (The old K10D Sony CCD is clocked at 25MHz);

4. As such, the Maximum Frame Rate of the sensor is low, too, at only 3 fps;

5. The Full Well Capacity at 65,000 electrons is large;

6. The Dark Current at a rate of 223 electrons per second is very low (which affect noise performance and dynamic range);

7. The Dynamic Range of 65.4 dB means a theoretical maximum DR of 10.86EV steps which is not too impressive, in contrast;

8. At a 3.3V operating voltage and a low operating frequency of 15MHz, this would be a low power consumption device (< 176mW as specified). But actually one thing I don't understand is about the DR spec in dB. If I have to calculate it from the Full Well Capacity to the Dark Current, it is only of 49.29 dB, which is yet lower than the published spec and the value is lower than typical, also. (If any of the imager experts read here, please enlighten me! TIA. :-))

Well, after all, actually there is no outsider knows at the current stage if Pentax is really making a Full Frame DSLR body, not even mention to which and what sensor in such a rumoured body. Btw, I think there are still other (limited) choices, but this Cypress CMOS would be a relatively much cheaper option, I bet. Performance wise, it is yet unknown. But normally I would not expect miracles from novices - even the electronics giant Samsung has been striking much for making a better APS-C sensor, with higher performance, better image quality and less bugs, frankly.

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