Dicussions on four new small CCDs IMX183, IMX294 IMX385, IMX390, ( and a bit on GSense2020 BSI )
From Albéric posted on Webastro:
For reading noise figures, be careful it depends on the gain and it also varies a bit from one sensor to another. In rapid CP, one works with high gain (60 to 90% approximately) values, but not at max gain.
On the noise values, I would rather set the sliders to these values, looks more reasonable to me:
IMX183: 1.3 e-
IMX224: 0.75 e-
IMX290: 1 e-
IMX178: 1.5 e-
Then a sensor with tiny 2.4 micron pixels is anything but soft and versatile. In deep sky it is limited to fast and expensive astrographs or a SC (Schmidt Cassegrain) equipped with Hyperstar. Want to equip a conventional Newton at F / 5 with an expensive reducer dedicated type ASA, it is also often embarking in a big galley side settings ...
With 4.63 micron pixels, you can easily use classical instruments telescope / telescope to F / D of 5 or 6. Or SC / Mak with a classic focal reducer. It is therefore an excellent compromise to do everything (fast CP, slow CP, lunar, planetary see solar if mono sensor) with the majority of the trade instrument, the same definition versatility. In addition it has an excellent frame rate, which can be increased in fenestrating, and its resolution of almost 11 Mpixel is roughly equivalent to that of a Sony A7S.
For the reading noise values, you have to reduce this value to the pixel size and the received stream.
IMX183: 5.8 micron2, reading noise of the order of 1.3 e-
IMX390: 9 micron2, reading noise of the order of 1 e-
IMX385: 14.1 micron2, reading noise of the order of 0.75 e-
IMX294: 21.1 micron2, reading noise of the order of 1.5 e- to 2 e-
To simplify things, considering a single monochrome sensor, with a QE "reasonable" means of 70% on the visible spectrum and arbitrary Illumination of 1 photon / micron2 / sec:
IMX183: 9x0.7 = 4.1 e- detected in 1 sec of exposure
IMX390: 9x0.7 = 6.3 e- detected in 1 sec of exposure
IMX385: 14.1 * 0.7 = 9.9 e- detected in 1 sec of exposure
IMX294: 21.1x0.7 = 14.8 e- detected in 1 sec of exposure
Dynamic range:
IMX183: 20 log (4.1 / 1.3) = 10 dB
IMX390: 20 log (6.31 / 1) = 16 dB
IMX385: 20 log (9.9 / 0.75) = 22 dB
IMX294: 20 log (14.8 / 1.5) = 20 dB for 1.5 e-
20 log (14.8 / 2) = 17.3 dB if based on 2 e-
If the estimates are accurate and if the glow amp remains unobtrusive or easy to remove, I maintain, the IMX294 is really a super super super sensor in all areas including in CP short poses where it will be perfect for a color type camera. The only real problem is clearly the lack of a monochrome version.
Regarding the IMX390, you forget two crucial numbers:-
- the frame rate:
60 image / sec in HD, to make it simple, it is a comeback 5 years late. Logically, Sony directly announces the color version, "Sony's new image sensor has addressed this issue by making the exposure time longer than the LED flicker frequency, "
Understanding that they simply limited the exposure time to a compatible minimum value with the frequency of these traffic lights.
- the saturation signal:
only 700 mV, is the lowest value of all in the table !
So it saturates faster than other sensors. In addition to CP short pose, one works at high gain so the dynamic range is already very limited. There it will be even worse!
I would not buy a camera with this sensor (IMX390) , it's very clear.
Albéric
Sony announcements:
here
From Albéric posted on Webastro:
For reading noise figures, be careful it depends on the gain and it also varies a bit from one sensor to another. In rapid CP, one works with high gain (60 to 90% approximately) values, but not at max gain.
On the noise values, I would rather set the sliders to these values, looks more reasonable to me:
IMX183: 1.3 e-
IMX224: 0.75 e-
IMX290: 1 e-
IMX178: 1.5 e-
Then a sensor with tiny 2.4 micron pixels is anything but soft and versatile. In deep sky it is limited to fast and expensive astrographs or a SC (Schmidt Cassegrain) equipped with Hyperstar. Want to equip a conventional Newton at F / 5 with an expensive reducer dedicated type ASA, it is also often embarking in a big galley side settings ...
With 4.63 micron pixels, you can easily use classical instruments telescope / telescope to F / D of 5 or 6. Or SC / Mak with a classic focal reducer. It is therefore an excellent compromise to do everything (fast CP, slow CP, lunar, planetary see solar if mono sensor) with the majority of the trade instrument, the same definition versatility. In addition it has an excellent frame rate, which can be increased in fenestrating, and its resolution of almost 11 Mpixel is roughly equivalent to that of a Sony A7S.
For the reading noise values, you have to reduce this value to the pixel size and the received stream.
IMX183: 5.8 micron2, reading noise of the order of 1.3 e-
IMX390: 9 micron2, reading noise of the order of 1 e-
IMX385: 14.1 micron2, reading noise of the order of 0.75 e-
IMX294: 21.1 micron2, reading noise of the order of 1.5 e- to 2 e-
To simplify things, considering a single monochrome sensor, with a QE "reasonable" means of 70% on the visible spectrum and arbitrary Illumination of 1 photon / micron2 / sec:
IMX183: 9x0.7 = 4.1 e- detected in 1 sec of exposure
IMX390: 9x0.7 = 6.3 e- detected in 1 sec of exposure
IMX385: 14.1 * 0.7 = 9.9 e- detected in 1 sec of exposure
IMX294: 21.1x0.7 = 14.8 e- detected in 1 sec of exposure
Dynamic range:
IMX183: 20 log (4.1 / 1.3) = 10 dB
IMX390: 20 log (6.31 / 1) = 16 dB
IMX385: 20 log (9.9 / 0.75) = 22 dB
IMX294: 20 log (14.8 / 1.5) = 20 dB for 1.5 e-
20 log (14.8 / 2) = 17.3 dB if based on 2 e-
If the estimates are accurate and if the glow amp remains unobtrusive or easy to remove, I maintain, the IMX294 is really a super super super sensor in all areas including in CP short poses where it will be perfect for a color type camera. The only real problem is clearly the lack of a monochrome version.
Regarding the IMX390, you forget two crucial numbers:-
- the frame rate:
60 image / sec in HD, to make it simple, it is a comeback 5 years late. Logically, Sony directly announces the color version, "Sony's new image sensor has addressed this issue by making the exposure time longer than the LED flicker frequency, "
Understanding that they simply limited the exposure time to a compatible minimum value with the frequency of these traffic lights.
- the saturation signal:
only 700 mV, is the lowest value of all in the table !
So it saturates faster than other sensors. In addition to CP short pose, one works at high gain so the dynamic range is already very limited. There it will be even worse!
I would not buy a camera with this sensor (IMX390) , it's very clear.
Albéric
below are new STARVIS sensors introduced in ShenZhen surveillance exhibition 2017:
IMX334, IMX335, IMX385, IMX327, IMX307
Sony announcements:
here
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