Samsung unveils 50MP ISOCELL JN1 camera sensor

10 June 2021
The sensor packs 0.64μm pixels and Double Super PD.

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  • Anonymous

Kurosava, 55 minutes agoYou have really no idea how pixels work. Smaller pixels h... more"I mentioned it a few times already, but you chose to ignore it."
No, I didn't ignore it, but you were not able to provide a source. As I said the sources of noise are photon noise, read noise and dark current noise. Read noise and fixed pattern noise is the noise you capture when you use a lens cap and a short exposure time, dark current noise is the additional noise you capture when the exposure time gets longer. There isn't another major noise source, unless you can provide a reliable source that says that there is another major noise source apart from read noise and dark current noise. The noise that is caused by the analog to digital conversion is read noise. It also doesn't matter what the reason for read noise, etc is. Small pixels don't really have more read noise than large pixels as I mentioned. That's why equivalence theories work. And this is also supported by measurements from photonstophotos.net . Smaller pixels can even have less read noise.

"Smaller pixel = lees photons = less shot noise"
Less photon noise per pixel, but not per object. The photon noise per object stays constant, no matter which pixel size.

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  • 24 minutes ago
  • pQr
  • Kurosava

Anonymous, 2 hours agoI didn't say that one can ignore read noise. And no, r... moreYou have really no idea how pixels work.
Smaller pixels have larger noise because of other factors - like smaller conversion capacitance. Which is different from readout noise. I mentioned it a few times already, but you chose to ignore it.
Then what you describe is called photon shot noise and it has a lot to do with the pixel size. It is actually better for smaller pixels, since they capture less photons. If number of photons hitting the pixel is S, then photon noise is sqrt(S) and is in direct relationship with the active area of the pixel. With abundance of light it is the dominant noise source. Smaller pixel = lees photons = less shot noise. But then a larger pixel achieves the same by reducing exposure time.

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  • 55 minutes ago
  • ndi
  • Kurosava

Anonymous, 1 hour agoYou think we can read your mind? You said small pixel size ... moreNo, I thought you have common sense.

  • Anonymous

Kurosava, 8 hours agoI though that striving for image quality is self-explanator... moreYou think we can read your mind? You said small pixel size makes exposure time longer. That statement is wrong. Period. I rest my case.

  • Anonymous

Anonymous, 2 hours agoI didn't say that one can ignore read noise. And no, r... moreIf you paint noise on your wallpaper and then you want to take a photo of your wallpaper (perfect light conditions), you wouldn't expect to see a better signal to noise ratio in your wallpaper photo, if you use a camera with a different pixel size. Though, this example isn't perfect because it only works, if the effective diameter of the lens stays constant.

  • Anonymous

Kurosava, 5 hours agoFirst, you can't ignore readout noise, since it is one... moreI didn't say that one can ignore read noise. And no, read noise isn't always the dominant noise source. In good light conditions without shadows, read noise isn't important. Also, read noise isn't necessarily that important, if there is a lot of light pollution. Furthermore, when you take a photo of an object with a 4 micrometer camera + 250mm lens, the object will have a similar amount of read noise as a 0.8 micrometer camera + 50mm lens because in both cases the object consists of the same number of pixels and the read noise per pixel will be similar (between 2 and 1 electrons per pixel). For example, an older iPhone or Pixel phone has a similar amount of read noise per pixel as a Canon M50 according to photonstophotos.net . Apart from photon noise and read noise, there isn't another major noise source. There is dark current noise, but this is only relevant for long exposures and I have seen no source that says that smaller pixels have more dark current per pixel. Indeed, there are many specialized astrophotography cameras with smaller pixels than Aps-c cameras. And not even every camera with large pixels has back side illumination.

"I am really curious how the noise of the object does not depend on the noise of the pixel that captures it."
The effective diameter determines how much light per time can be captured from an object. This doesn't depend on the pixel size as a sensor can only capture the light that goes through the lens. Photon noise is the variation of the number of photons that are emitted/reflected per time, so it has nothing to do with the pixel size. Of course the pixel size doesn't affect the photon noise of an object (unless the pixels are less effective and lose light), otherwise it wouldn't be called photon noise, but read noise or something else. Photon noise is part of the reality and affects our eyes as well.

  • Kurosava

Anonymous, 6 hours ago"a sensor with a 4um pixel and a 250mm/f10 lens will a... moreFirst, you can't ignore readout noise, since it is one of the major noise contributors. Second, even if you ignore the readout noise, a smaller pixel will still have larger noise from other sources like kTc. This is simple semiconductor physics. Then as I already said you will have bloom due to optical crosstalk. Especially when pixels become so small that they are comparable to the wavelength. Plus all the other drawbacks like dynamic range.
The only advantage is the increase sensor MTF, which will allow you to see smaller objects. I am really curious how the noise of the object does not depend on the noise of the pixel that captures it.

  • Anonymous

Kurosava, 8 hours agoYes, you can capture only as much light as the lens permits... more"a sensor with a 4um pixel and a 250mm/f10 lens will always perform better than a sensor with 0.8u pixels and a 50mm/f2 lens"
No, small pixels don't have more read noise per pixel than large pixels. Read noise is the important factor. I have never heard that the fill factor is worse for small pixels. If the fill factor was significantly different for small pixels, then simple camera equivalence theories wouldn't work at all, but they do work for cameras of the same generation.

When you take a photo of a distant object, one doesn't care about the noise per pixel, but the noise of the object. These are totally different things. So, when I ignore read noise and demosaicing and judge the noise of a distant object, it doesn't really matter whether I use a 125mm f/5 lens, a 250mm f/10 lens or a 500mm f/20 lens and it doesn't really matter which pixel size I use. Only when you take read noise into account, a high number of pixels per object will lead to significantly worse results in low-light conditions.

  • Kurosava

Anonymous, 22 hours agoNote that pixel size or sensor size does not affect how muc... moreYes, you can capture only as much light as the lens permits. But pixel size makes difference how good you can utilize the light that enters the lens. Smaller pixels capture less photons than large pixels. Then smaller pixels have larger noise. So total signal to noise ratio is worse. So no, a sensor with a 4um pixel and a 250mm/f10 lens will always perform better than a sensor with 0.8u pixels and a 50mm/f2 lens, as long as all the rest is the same. The signal level will be the same, but the noise for the smaller pixel will be higher. So overall SNR will be worse. And this is on individual pixel level. If you consider optical and electrical crosstalk gets worse with pixel size going down, then the picture gets even worse.

  • Kurosava

Anonymous, 18 hours agoThat wasn't what you said. I quote "With this pix... moreI though that striving for image quality is self-explanatory and does not need to be mentioned explicitly. In the end, the purpose is to capture a nice image, not just some noisy gibberish. If the purpose is to have bad images with poor color accuracy, narrow dynamic range, lots of noise and so on, then small pixels are much better than large ones.

  • Anonymous

aadddd, 11 Jun 2021People here really believe that full frame and smarphone ca... moreErm who? You?

  • Anonymous

Kurosawa, 11 Jun 2021Which means, you will need much longer exposure time to get... moreThat wasn't what you said. I quote "With this pixel size all exposures will ve long". You didn't mention anything about image quality.

  • Anonymous

Anonymous, 22 hours agoNote that pixel size or sensor size does not affect how muc... moreNote that even 0.8 micrometer pixels + 250mm f/10 lens or a 2500mm f/100 lens would still capture the same amount of light per time from a small galaxy, the difference would be that the galaxy consists of many more pixels and this leads to more read noise.

  • Anonymous

Note that pixel size or sensor size does not affect how much light per time you capture from an object, if you use exactly the same lens. A sensor can only capture the light that goes through the lens. So it doesn't really matter whether you photograph a galaxy with small pixels or large pixels as long as the effective diameter of the lens is the same and as long as the number of pixels per angle is the same. When you take a photo of a galaxy, a 54 megapixel full frame camera with 4.0 micrometer pixels and 250mm f/10 lens will perform similar to a tiny sensor with 0.8 micrometer pixels and 50mm f/2 lens.

  • Anonymous

The one they gave xiaomi with 50 individual 1.4um pixels is far superior

  • aadddd

People here really believe that full frame and smarphone capture same amount of light? Dont bother with photograpy, you need at least 50 IQ, you can only dream for IQ like this

  • Kurosawa

Nick Tegrataker, 11 Jun 2021..which does not contradict my initial argument that the ex... moreWhich means, you will need much longer exposure time to get the comparable image. Actually you will never get the same image, since smaller pixels will always be more noisy than large pixels and have less dynamic range. Especially in low light conditions, where dominating noise is kTC and conversion noise.

Anonymous, 11 Jun 2021Exposure time is determined by ISO and aperture size only. ... moreI've shot a lot of manuals on my Canon 600D.

Shutter speed is determined by an actual moving shutter which has a mirror. Ok? It opens and closes as per shutter speed we decide which is in seconds or its units.

ISO is sensitivity of the sensor and higher ISO means more light and noise.

Aperture is like a set of moving, multiple blades which create a hole between them.

Together they decide the exposure of the picture, in conjunction with the actual light we have.

P is Programmed Automatic.
A is Aperture priority in which I decide aperture and rest camera decides as per its decided ideal exposure.
S is Shutter priority in which I decide shutter speed and rest camera decides as per its decided ideal exposure.
M is full manual in which I decide it all.
Rest of the modes are not relevant, except video.

I admit I was wrong about bigger pixel size giving more light. This is because I have maturity, unlike you and I checked.
Just because I didn't know one thing, doesn't give you license to speak rubbish. What's your age by the way? I have a guess but still?

Kurosawa, 11 Jun 2021Yes, but you will get two totally different images, because... more..which does not contradict my initial argument that the exposure will be the same. I never implied that those images will be remotely close to being similar in terms of SNR and raw dynamic range.

  • Kurosawa

Nick Tegrataker, 11 Jun 2021It doesn't. Assuming that both sensors use exactly the... moreYes, but you will get two totally different images, because of the different pixel size. Either under or overexposed or extremely noisy, depending on the exact illumination conditions.