Win a Pentax Limited Lens: Raffle Now Live!

Eruditass · 09-18-2009, 09:57 AM

Originally posted by kibipod

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!

Blue · 09-18-2009, 10:58 AM

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/

jct us101 · 09-18-2009, 11:54 AM

Yeah I was pretty much just being an ass.

At least you were all asses back to me.

falconeye · 09-21-2009, 07:04 AM

Originally posted by jct us101

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:

Filter coefficient for white light (#photons hitting the photo sensitive area / #photons hitting sensor cell area) -- this depends on filter colors and microlens design
Quantum efficiency after filter
Sometimes, the former two parameters are combined into a single "pixel sensitivity" figure, measured in [Vm^2/Ws].
Full well capacity of a single dot
Number of pixels (dots)
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.

creampuff · 09-21-2009, 07:33 AM

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

creampuff · 09-21-2009, 07:35 AM

More pictures to chill out...

K-x with DFA 50mm Macro

K-x with DA 70mm Limited

gazonk · 09-21-2009, 08:04 AM

Originally posted by creampuff

More pictures to chill out...

K-x with DA 70mm Limited

Hmm, that looks much better than my DA70 on my K-10D!

Peter Zack · 09-21-2009, 02:54 PM

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.....

Blue · 09-21-2009, 03:29 PM

What did you do Creampuff, catch Ned B. on a trip and mug him while he was playing with his D-Lux-4?

creampuff · 09-21-2009, 09:56 PM

Originally posted by Blue

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...

ogl · 09-21-2009, 10:10 PM

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.

Eruditass · 09-21-2009, 10:21 PM

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.

ogl · 09-21-2009, 10:30 PM

Originally posted by Eruditass

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.

hinman · 09-21-2009, 10:42 PM

Originally posted by ogl

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

ogl · 09-21-2009, 11:37 PM

Originally posted by hinman

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.

09-21-2009, 07:04 AM	#34
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871	Originally posted by jct us101 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: Filter coefficient for white light (#photons hitting the photo sensitive area / #photons hitting sensor cell area) -- this depends on filter colors and microlens design Quantum efficiency after filter Sometimes, the former two parameters are combined into a single "pixel sensitivity" figure, measured in [Vm^2/Ws]. Full well capacity of a single dot Number of pixels (dots) 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 0.910^12 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.*

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Sample size of photos to email	jbrowning	Photographic Industry and Professionals	12	08-24-2009 08:24 PM
Sample K7 photos some with high ISO	pastorbbc	Pentax DSLR Discussion	0	07-05-2009 06:22 PM
Rokinon 800mm Sample Photos (10 pics)	MightyMike	Post Your Photos!	7	06-19-2009 07:40 PM
Fuji 800Z Sample Photos	k100d	Film SLRs and Compact Film Cameras	11	03-29-2009 05:28 PM
Sample Photos from a Cosina 50/1.4 MF lens.	frank	Pentax SLR Lens Discussion	21	12-28-2008 11:37 PM

09-18-2009, 09:57 AM	#31
Eruditass Veteran Member Join Date: Jul 2009 Photos: Gallery Posts: 2,207	Originally posted by kibipod 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
Blue Moderator Site Supporter Join Date: Jun 2008 Location: Florida Hill Country Photos: Gallery \| Albums Posts: 17,377	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
jct us101 Veteran Member Join Date: Jun 2008 Location: Rohnert Park, CA Posts: 3,793	Yeah I was pretty much just being an ass. At least you were all asses back to me.

09-21-2009, 07:33 AM	#35
creampuff Veteran Member Join Date: May 2007 Location: Singapore Photos: Gallery Posts: 3,953	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
creampuff Veteran Member Join Date: May 2007 Location: Singapore Photos: Gallery Posts: 3,953	More pictures to chill out... K-x with DFA 50mm Macro K-x with DA 70mm Limited

09-21-2009, 08:04 AM	#37
gazonk Pentaxian Join Date: Feb 2009 Location: Oslo area, Norway Photos: Gallery \| Albums Posts: 3,746	Originally posted by creampuff 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
Peter Zack Pentaxian Moderator Emeritus Join Date: May 2007 Location: Edmonton Alberta, Canada Photos: Gallery \| Albums Posts: 10,643	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
Blue Moderator Site Supporter Join Date: Jun 2008 Location: Florida Hill Country Photos: Gallery \| Albums Posts: 17,377	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
creampuff Veteran Member Join Date: May 2007 Location: Singapore Photos: Gallery Posts: 3,953	Originally posted by Blue 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
ogl Banned Join Date: Dec 2007 Location: Sankt Peterburg Photos: Gallery \| Albums Posts: 8,382	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
Eruditass Veteran Member Join Date: Jul 2009 Photos: Gallery Posts: 2,207	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
ogl Banned Join Date: Dec 2007 Location: Sankt Peterburg Photos: Gallery \| Albums Posts: 8,382	Originally posted by Eruditass 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
hinman Veteran Member Join Date: Oct 2006 Location: Fremont, CA Photos: Albums Posts: 3,473	Originally posted by ogl 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
ogl Banned Join Date: Dec 2007 Location: Sankt Peterburg Photos: Gallery \| Albums Posts: 8,382	Originally posted by hinman 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.

Sample photos of K-x

Win a Pentax Limited Lens: Raffle Now Live!