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10-16-2019, 04:09 AM   #1
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Mp count + sensor size & Imaging output

Hi! Here is a potentially technically-obvious question you can help me with:

I am curious about what happens when you shoot with a lower megapixel count on a sensor like the K3II's (24mp). Is there any benefit in terms of color rendition, dynamic range, etc? (provided you don't care about printing, cropping and pixel peeping).

I have read a lot about how certain old cameras, like the Nikon D700 or the Canon 5D, have a "legendary" image output because of –in addition to their color processing and many etc.– a "magical quality of spreading 12 mp accross the size of a full frame sensor". I swear I must be quoting someone on this, credit where it is due. So I am wondering if I would obtain any benefit from shooting my K3II at 14mp on purpose, depending on the assignment. I am aware that the k3II has an APS-C sensor smaller than the Fx cameras I mentioned.

Thank you for you help.

10-16-2019, 04:18 AM - 1 Like   #2
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QuoteOriginally posted by Mørkus Quote
I am curious about what happens when you shoot with a lower megapixel count on a sensor like the K3II's
You cannot shoot at less than 24MP on the K3II ?

Do you mean use a lower quality JPEG ? In that case the image file is downsized by the camera software after it has been captured.
10-16-2019, 05:47 AM   #3
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Urban legends !! Fanboy of Nikon and Canon.
10-16-2019, 05:59 AM - 2 Likes   #4
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All other things being equal the camera with the larger pixel pitch will produce better quality images with less noise. However not all other things are equal so it becomes rather pointless to compare just off of pixel pitch. Basically a larger pixel results in that pixel being able to count more photons and provide a better representation of the actual light value of the image at that location. Additionally a larger pixel means that the image becomes diffraction limited at a larger f-stop. However technology marches along and the quantum efficiency of each pixel has increased, the supporting electronics have shrunk so that they take up less space blocking fewer photons, the energy consumption and heat production of the sensor has gone down as feature sizes have shrunk, lower noise electronics have become better, and now with back side illuminated sensors moving the supporting electronics to the side of the sensor that isn't gathering photons it should become clear that pixel size isn't the only factor in determining image quality.

If you wanted shoot your K-3 at a lower resolution really the only one you could reasonably do would be 6MP and instead of debayering the image you would treat each group of 4 pixels as a single pixel and have full RGB information like one would get with pixel shift. However instead of having a 24MP image you now have a 6MP image. This is not down sampling using photoshop to 6MP from 24 as you would have already debayered the image and would have been working with interpolated information. I know with some astro image processors they have a super pixel mode that does this but I'm not sure about other tools.

10-16-2019, 06:01 AM - 1 Like   #5
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QuoteOriginally posted by pschlute Quote
You cannot shoot at less than 24MP on the K3II ?

Do you mean use a lower quality JPEG ? In that case the image file is downsized by the camera software after it has been captured.
There we go,I guess that is what I meant. I refer to setting the "number of recorded pixels" smaller than L** in the menu. If what the camera does is to compress the jpeg after capture, that immediately answers my question.

Thank you.

---------- Post added 10-16-19 at 06:06 AM ----------

QuoteOriginally posted by MossyRocks Quote
All other things being equal the camera with the larger pixel pitch will produce better quality images with less noise. However not all other things are equal so it becomes rather pointless to compare just off of pixel pitch. Basically a larger pixel results in that pixel being able to count more photons and provide a better representation of the actual light value of the image at that location. Additionally a larger pixel means that the image becomes diffraction limited at a larger f-stop. However technology marches along and the quantum efficiency of each pixel has increased, the supporting electronics have shrunk so that they take up less space blocking fewer photons, the energy consumption and heat production of the sensor has gone down as feature sizes have shrunk, lower noise electronics have become better, and now with back side illuminated sensors moving the supporting electronics to the side of the sensor that isn't gathering photons it should become clear that pixel size isn't the only factor in determining image quality.

If you wanted shoot your K-3 at a lower resolution really the only one you could reasonably do would be 6MP and instead of debayering the image you would treat each group of 4 pixels as a single pixel and have full RGB information like one would get with pixel shift. However instead of having a 24MP image you now have a 6MP image. This is not down sampling using photoshop to 6MP from 24 as you would have already debayered the image and would have been working with interpolated information. I know with some astro image processors they have a super pixel mode that does this but I'm not sure about other tools.
I appreciate that you took the time to bring together a series of highly-specific, relevant and interrelated concepts. It would have taken many hours of research to eventually piece those together on my own. This will sure be of value next time I consider diversifying my tools. Thank you.

Have a nice day

Last edited by Mørkus; 10-16-2019 at 06:07 AM.
10-16-2019, 06:31 AM - 1 Like   #6
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QuoteOriginally posted by Mørkus Quote
There we go,I guess that is what I meant. I refer to setting the "number of recorded pixels" smaller than L** in the menu. If what the camera does is to compress the jpeg after capture, that immediately answers my question.

Thank you.

---------- Post added 10-16-19 at 06:06 AM ----------


I appreciate that you took the time to bring together a series of highly-specific, relevant and interrelated concepts. It would have taken many hours of research to eventually piece those together on my own. This will sure be of value next time I consider diversifying my tools. Thank you.

Have a nice day
Actually I worry less about sensor tech and more about the features offered by the camera when I buy. Unless you are really pushing the capabilities of your gear in rather extreme shooting environments (I do with astrophotography) we are really at the point where in normal circumstances the sensor doesn't matter all that much for image quality. Having a good autofocus, and quality glass matter much more for the vast majority of images than the sensor behind the glass but the person behind the camera matters the most. I've demonstrated this when doing photography merit badge with some scouts who believe that it is the camera that makes the pictures great. The first scout to state this we go and take a trip out side as a group and I let the scout pick a subject, use my K-3 and pick what ever nice lens they want and shoot the image. I will grab one of the old canon PowerShot G2 cameras (donated by a parent who worked for the company that did the cameras for the MN DMV and were the ones that got replaced probably 2 cycles ago) that I have for scouts to check out. I have yet to have a scout take a better picture, even if the image quality is better it is just a better quality image of a poorly shot picture.
10-16-2019, 08:01 AM - 1 Like   #7
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There is a road you can explore. Adobe DNG Converter allows you to use loosy compression when you convert a RAW file. With loosy compression you can choose to reduce the pixel count.

I mostly shoot in RAW and sometimes in 'JPEG M'. But I'm so used to RAW format that what I do for casual pics is to shoot in RAW but use DNG converter to compress and reduce the pixel count to 14Mp. I get a good RAW file that is better than a JPEG on camera.
I don't know if you could cancel the effects of interpolation by choosing a 6Mp pixel count, because this is a compressed format with some loss of data, but you can play with it, and see if you get a pic with less noise, sharper, etc.

BTW, I have the K3-II too.
10-16-2019, 08:30 AM - 1 Like   #8
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Great explanations above!

As for the magic of the 5D or D700, you have to take it in the context of their era. They were the first affordable FF digital cameras and thus were groundbreaking. APS-C sensors were struggling to have decent IQ at 400ISO. So a sensor able to provide a usable output at ISO 800 or 1600 really was magical. But today, it’s not really impressive. Any modern APS-C sensor will perform better than these old FF, even if they were great in their time.

10-16-2019, 08:36 AM - 1 Like   #9
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QuoteOriginally posted by morenjavi Quote
I don't know if you could cancel the effects of interpolation by choosing a 6Mp pixel count, because this is a compressed format with some loss of data, but you can play with it, and see if you get a pic with less noise, sharper, etc.
That is why I said using a super pixel method instead of debayering the image and then down sampling. You avoid the whole interpolation step and would see those improvements in noise and sharpness like you get with a pixel shift image but at a cost of having a 6MP image instead of a 24MP image. If you have an OOC jpeg you are already screwed as you've done what ever debayering method the camera uses, used lossy compression, and pitched a bunch of data to get to 8bpc from the 14 you get in raw.
10-16-2019, 09:12 AM - 1 Like   #10
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Less of the larger pixels or more of the smaller pixels on the same sensor area, is like the size of the squares on 250gr of chocolate, is still 250gr of chocolate I'm afraid.
10-16-2019, 09:38 AM - 1 Like   #11
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You might also want to consider a used k10d for the large pixels and ccd vs cmos technology. Ultimately I think it is not that large a difference.

The k5iis is another idea. Slightly larger pixels with good noise characteristics.

Personally I would not expect a huge Delta but it could be a fun ride trying out things.
10-16-2019, 11:46 AM   #12
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QuoteOriginally posted by CarlJF Quote
Great explanations above!

As for the magic of the 5D or D700, you have to take it in the context of their era. They were the first affordable FF digital cameras and thus were groundbreaking. APS-C sensors were struggling to have decent IQ at 400ISO. So a sensor able to provide a usable output at ISO 800 or 1600 really was magical. But today, it’s not really impressive. Any modern APS-C sensor will perform better than these old FF, even if they were great in their time.
Thank you for providing a useful perspective which is hard to have for me, as I was not into the photography world during all those years. When I have come across such reviews of those cameras in 2019, I have tended to gravitate to the ideas you mentioned. I am very happy with the results of the K3II for professional work always shooting RAW. But I do have to post process almost 100% of the time to fix the warmer tones and some colours. Although I guess this is entirely subjective.

---------- Post added 10-16-19 at 11:56 AM ----------

QuoteOriginally posted by MossyRocks Quote
Actually I worry less about sensor tech and more about the features offered by the camera when I buy. Unless you are really pushing the capabilities of your gear in rather extreme shooting environments (I do with astrophotography) we are really at the point where in normal circumstances the sensor doesn't matter all that much for image quality. Having a good autofocus, and quality glass matter much more for the vast majority of images than the sensor behind the glass but the person behind the camera matters the most. I've demonstrated this when doing photography merit badge with some scouts who believe that it is the camera that makes the pictures great. The first scout to state this we go and take a trip out side as a group and I let the scout pick a subject, use my K-3 and pick what ever nice lens they want and shoot the image. I will grab one of the old canon PowerShot G2 cameras (donated by a parent who worked for the company that did the cameras for the MN DMV and were the ones that got replaced probably 2 cycles ago) that I have for scouts to check out. I have yet to have a scout take a better picture, even if the image quality is better it is just a better quality image of a poorly shot picture.
I agree wholeheartedly with your approach. I looked into the d700 mainly because I own some Nikon glass which I use to shoot film on an F100. Since the AF system on the K3II with a SMC Pentax-F 28mm 2.8 lens & the Tamron 17-50mm 2.8 has disappointed me at times, I started wondering if the D700 could offer a different experience worth the investment. I am not looking to replace the K3II, but for shooting events, I wonder. Either that, or adding the AF 50mm 1.8 from Pentax to replace my M series 50 1.7
As I said in other replies, it is easy to come by biased and inflated information, and it is difficult to maintain perspective sometimes.

Thank you very much to everybody for taking the time to reply. Have a nice day.

Last edited by Mørkus; 10-16-2019 at 12:09 PM.
10-16-2019, 11:57 AM - 1 Like   #13
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If you want to shoot at 14 MP in RAW, here is a suggestion: I have a 14 MP K-7 which I'd be happy to swap for your K-3ii. Not sure if you'd get some benefit from such a move, but I certainly would...
10-16-2019, 07:39 PM - 1 Like   #14
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Your opening post makes me think of how people are nostalgic for certain sensor technologies and corresponding colors. I believe the CCD sensor of Leica M9 was designed in conjunction with Kodak and was known for being like Kodachrome in it's color rendition. There was a thread here awhile back on setting up LightRoom for CCD like colors from the K-3: https://www.pentaxforums.com/forums/61-post-processing-articles/350673-get-c...lightroom.html
11-01-2019, 04:01 AM   #15
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QuoteOriginally posted by Mørkus Quote
Hi! Here is a potentially technically-obvious question you can help me with:

I am curious about what happens when you shoot with a lower megapixel count on a sensor like.......

I experienced this a long time ago on the beginnings of digital cameras, because I had little room on the card. Other than the fact that I filled the card with lower resolution photos, much lower quality than normal ones, there was no benefit. I would not repeat that.
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