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09-18-2009, 09:57 AM   #31
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QuoteOriginally posted by kibipod Quote
Let me see if I understand it correctly. OP started with Kx pics...........and now we are talking about what?

I have a cool Kx pic people...it is a pic of the camera and not a pic taken by the camera. So what.......let us enjoy it
If only the lens was blue too!

09-18-2009, 10:58 AM   #32
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This edition of the K-x will be an attention grabber one way or another.



http://k-rumors.com/the-new-pentax-k-x-with-12-4mp-720p-video-coming-october-for-650/
09-18-2009, 11:54 AM   #33
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Yeah I was pretty much just being an ass.

At least you were all asses back to me.
09-21-2009, 07:04 AM   #34
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QuoteOriginally posted by jct us101 Quote
The mathematical formula for ISO only allows 200 to be a true base.
Because you have stirred up the topic, here is input

The mathematical formula for base ISO for a given sensor will be a function of five parameters:
  1. Filter coefficient for white light (#photons hitting the photo sensitive area / #photons hitting sensor cell area) -- this depends on filter colors and microlens design
  2. Quantum efficiency after filter
    Sometimes, the former two parameters are combined into a single "pixel sensitivity" figure, measured in [Vm^2/Ws].
  3. Full well capacity of a single dot
  4. Number of pixels (dots)
  5. Area
Because you are so well informed, I kindly ask you to provide the exact formula (I may be able to help you here ) and the four parameter values. That's the least you could do after your estimed contribution to the forum.

To give you a run start, these three parameters for the Cypress 14MP full frame CMOS sensor (IBIS 1400) are:
  • Sensitivity: 1256 Vm^2/Ws
  • Full well capacity: 65000 electrons
  • Number of dots: 13898880
  • Area: 24 x 36 mm
Numbers unavailable for most CMOS sensors though.

Now, your turn to apply your "mathematical formula". Good luck


BTW ...
A full well capacity of 65000 electrons means that the Poisson shot noise limits the noise freedom of a single bright pixel to 7.99 Bits (log2(65000)/2).

Note that noise and the dynamic range of a sensor is determined by the total full sensor capacity which is 0.9*10^12 electrons (~1 trillion).


This is in line with my own lab tests for K20D ISO 100 shot noise which yields single bright pixel noise after 7.7 Bits. Which corresponds to a full well capacity of 43000 electrons for the K20D. A difference of 0.6 Bits would have been what to expect from the pixel size difference.

What is nice is that the read-out noise for the Cypress sensor is specified as well: "kTC noise" of 35 electrons and "dark current" of 223 electrons/s.


Last edited by falconeye; 09-21-2009 at 07:51 AM.
09-21-2009, 07:33 AM   #35
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Enough of the tech talk guys... you all need to chill out by looking at pictures to induce LBA/CBA

K-x with DA 15mm Limited


K-x with DA 21mm Limited


K-x with DA 40mm Limited
09-21-2009, 07:35 AM   #36
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More pictures to chill out...

K-x with DFA 50mm Macro


K-x with DA 70mm Limited
09-21-2009, 08:04 AM   #37
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QuoteOriginally posted by creampuff Quote
More pictures to chill out...
K-x with DA 70mm Limited
Hmm, that looks much better than my DA70 on my K-10D!
09-21-2009, 02:54 PM   #38
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Geez Creampuff, are you trying to force me out of LBA remission? Crap those all look good.

Lets stay on topic please and just drool.....

09-21-2009, 03:29 PM   #39
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What did you do Creampuff, catch Ned B. on a trip and mug him while he was playing with his D-Lux-4?
09-21-2009, 09:56 PM   #40
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QuoteOriginally posted by Blue Quote
What did you do Creampuff, catch Ned B. on a trip and mug him while he was playing with his D-Lux-4?
Ha, ha... guess we all need to give him a break.
Don't pooh, pooh the D-Lux-4... when I'm not using my Pentax, I'm using the cheaper but just as good Panasonic Lumix LX-3. Now if only the compact PnS people at Pentax can come up with an LX-3 clone...
09-21-2009, 10:10 PM   #41
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It seems to me that K-x's end picture could be better than K-7's.
Less noise, other colours, no magenta with skintones. IMO.
09-21-2009, 10:21 PM   #42
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here's hoping the sensor is better than the K-7's, although somehow I have doubts that pentax would do that to their flagship model.
09-21-2009, 10:30 PM   #43
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QuoteOriginally posted by Eruditass Quote
here's hoping the sensor is better than the K-7's, although somehow I have doubts that pentax would do that to their flagship model.
K200D has a bit better picture than K10D.
09-21-2009, 10:42 PM   #44
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QuoteOriginally posted by ogl Quote
It seems to me that K-x's end picture could be better than K-7's.
Less noise, other colours, no magenta with skintones. IMO.
What are you smoking? Share it with me. Are you kicking my sorry a. to go after a K-x than a K-7. Pentax will hire the black sniper to correct your smoking thoughts. Seriously, your opinion can save me the cost for a 12-24 lens

Thanks,
Hin
09-21-2009, 11:37 PM   #45
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QuoteOriginally posted by hinman Quote
What are you smoking? Share it with me. Are you kicking my sorry a. to go after a K-x than a K-7. Pentax will hire the black sniper to correct your smoking thoughts. Seriously, your opinion can save me the cost for a 12-24 lens

Thanks,
Hin
Sensor is a bit bigger, less MP.
We saw this sensor in D90, D300, D300s and D5000. Very good high ISO.
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