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Old 29-10-2017, 07:12 PM
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Possibly Sony's new embodiment of ICX694 ?

Hi all,

I noticed that Sony recently announced a few new CMOS censors. IMX428LLJ in particular caught my attention. It has similar resolution, pixel size and dimensions to ICX694 that became quite popular among amateur astrophotographers in the past years.

Not sure if I read the specs correctly, but the new sensor seems to have a higher sensitivity than ICX694. If it also has a lower read noise and is cheaper, then maybe we will see it implemented in some astro cameras?

Specs for the new sensor:
http://www.sony-semicon.co.jp/produc...8LLJ_Flyer.pdf

I could not find specs for ICX694 on Sony's website, so this may have to do: http://www.neutronoptics.com/icx694.pdf
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Old 30-10-2017, 10:24 AM
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Yup, that'll be the 694's successor, but _gasp_ a CMOS chip?!?

The sensitivity is good, although not as good as the 294 (BSI) and 224 which are ~2350mV. The read noise will be ~2e or better as it's using the High Conversion Gain feature as on most Sony sensors nowadays.
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Old 30-10-2017, 01:15 PM
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Quote:
Originally Posted by Camelopardalis View Post
Yup, that'll be the 694's successor, but _gasp_ a CMOS chip?!?

The sensitivity is good, although not as good as the 294 (BSI) and 224 which are ~2350mV. The read noise will be ~2e or better as it's using the High Conversion Gain feature as on most Sony sensors nowadays.
IMX224 has sensitivity of 2350mV, but that is at f5.6, while stated 1600mV sensitivity for IMX428 is measured at f8. This indicates that IMX428 is significantly more sensitive than 224, possibly because it also has larger pixels.
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Old 30-10-2017, 02:18 PM
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Indeed, Sony tends to quote f/8 for their mono sensors and f/5.6 for OSC, while they "advocate" (my quotes) SNR1s instead.

Taking the f-ratio into account and halving the value for the IMX224 => 1175mV, then multiplying by the pixel area ratio of 1.44:1 gives 1692 for the IMX224. Be happy to learn what I'm estimating wrongly.

We'll probably have to wait and see how it looks when we have more data...
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Old 30-10-2017, 02:40 PM
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Your calculations look correct to me Dunk.

Closer inspection of Sony's datasheets cause even more confusion, to me anyway, and it makes it harder to compare their sensors. For example, for IMX224 they state G sensitivity, whatever that means.

We still need to wait for the final numbers for sensitivity for the mono version of IMX428, since quoted 1600mV at f8 is only an estimate, according to Sony. No doubt sensitivity is higher (3200mV vs 2350mV both at f5.6), but QE might be about the same or lower.

And whether anyone will implement these in astro cameras, that is a different story.

EDIT:

Just found Sony's data sheet for ICX694, with its 4.54micron pixels this excellent and popular CCD has a sensitivity of 1000mV at f8. So if the new IMX428 with its 4.5 micron pixels has a sensitivity of 1600mV at f8, that would indicate a significant improvement.

Would be interesting to see how read noise, dark current and well depth compare for the two. Perhaos saturation signal can give an indication of well depth? It is 520mV for ICX814, 800mV for ICX694 and 1000mV for IMX428.

Last edited by Slawomir; 30-10-2017 at 05:56 PM.
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Old 30-10-2017, 09:12 PM
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G sensitivity would be Green - IMX224 is OSC. No doubt mono is more desirable...they’ve not had a decent sized mono CMOS until recently (IMX183 also).

PtGrey are offering other IMX42x family cameras, so we shouldn’t have to wait long to find out, hopefully.

The only things that concern me in the specs are the 12-bit ADC and the lack of BSI. Not that either are a deal breaker, like you say QE and noise are what really counts. The recent IMX294 has a 14-bit ADC and BSI and low light sensitivity almost the equal of the 224, but is sadly OSC also
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