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ZWO ASI 294 MM PRO: First impressions and test images.

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#51 Peregrinatum

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Posted 08 September 2020 - 08:35 AM

Interesting development.... possibly priced close to the colored version?

 

Etendue would be about 2x that of the ASI1600MM, and 1.5x the ASI2600MM OR QHY268M, whats' not to like about a potential ASI294MM?



#52 Dean J.

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Posted 08 September 2020 - 08:45 AM

It should be a decent camera for those who don’t want to pay for the larger APS-C or full frame versions.  It would be nice to see some specs.


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#53 CCD-Freak

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Posted 08 September 2020 - 08:52 AM

Since the 294 color is one of the lower cost cameras we can only hope the mono version follows that trend.   I will be very interested to see how it is priced.

 

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#54 Peregrinatum

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Posted 08 September 2020 - 08:54 AM

ZWO has a decent thread going on now about this camera on their FB page, they confirm the IMX492 sensor, and availability within the next month.



#55 Peregrinatum

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Posted 08 September 2020 - 08:58 AM

IMX492 sensor specs from Sony:

 

12 bit

2.315 um pixels

42 M pixels

QE ???

 

https://www.sony-sem...J_LQJ_Flyer.pdf


Edited by Peregrinatum, 08 September 2020 - 09:03 AM.


#56 MikiSJ

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Posted 08 September 2020 - 02:44 PM

I did a quick comparison of the data sheets for the IMX294CJK and the IMX492LLJ_LQJ and it appears that the major difference between the two sensors is that Sony bins four (2X2) pixels in the 294 sensor to get a 4.63 pixel, whether is it is an R or G or B pixel.

 

The image here is from the Sony data sheet for the 294: Capture.JPG

 

If my reading is correct then the 294 sensor should be capable of being made a MM version simply by a firmware change an that is likely what Sony is doing with the 494. The question then becomes whether a sensor with 2.315µm in the 494 is better than the binned 4.63µm of the 294. I don't know if the lensing for each individual pixel in the sensor is colored for the 294, but that seems unlikely as the cost to manufacture colored lens would be impractical.


Edited by MikiSJ, 08 September 2020 - 02:45 PM.


#57 aatdalton

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Posted 08 September 2020 - 03:59 PM

The real question will be whether ZWO allows the sensor to be "unlocked" and choose between 2.3 vs 4.6 in software or if they want to sell two different cameras.

 

Would be fairly telling of them as a company.



#58 Peregrinatum

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Posted 08 September 2020 - 04:42 PM

Even if the camera does not unlock binning it will still be desirable imo, considering it could potentially cut my NB sub exposures in half compared to the ASI1600MM, with no micro lensing issue... and equally as compelling is if the price point was similar to the ASI294MC



#59 Dean J.

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Posted 08 September 2020 - 05:37 PM

Even if the camera does not unlock binning it will still be desirable imo, considering it could potentially cut my NB sub exposures in half compared to the ASI1600MM, with no micro lensing issue... 

How would that be possible?

 

That would be great if true.


Edited by Dean J., 08 September 2020 - 05:41 PM.


#60 rockstarbill

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Posted 08 September 2020 - 05:50 PM

I did a quick comparison of the data sheets for the IMX294CJK and the IMX492LLJ_LQJ and it appears that the major difference between the two sensors is that Sony bins four (2X2) pixels in the 294 sensor to get a 4.63 pixel, whether is it is an R or G or B pixel.

The image here is from the Sony data sheet for the 294: Capture.JPG

If my reading is correct then the 294 sensor should be capable of being made a MM version simply by a firmware change an that is likely what Sony is doing with the 494. The question then becomes whether a sensor with 2.315µm in the 494 is better than the binned 4.63µm of the 294. I don't know if the lensing for each individual pixel in the sensor is colored for the 294, but that seems unlikely as the cost to manufacture colored lens would be impractical.


You would need to remove the bayer matrix from the color sensor. That's physically added on top of the chip itself for a color camera. You can't just change the firmware and make the color 294 a mono 294.
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#61 Dean J.

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Posted 08 September 2020 - 06:38 PM

You would need to remove the bayer matrix from the color sensor. That's physically added on top of the chip itself for a color camera. You can't just change the firmware and make the color 294 a mono 294.

... so ZWO would have to order a special batch with a clear micro lens surface instead of the Bayer matrix?



#62 MikiSJ

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Posted 08 September 2020 - 06:45 PM

The real question will be whether ZWO allows the sensor to be "unlocked" and choose between 2.3 vs 4.6 in software or if they want to sell two different cameras.

Most camera drivers allow for binning so it should be trivial to bin 2x2 to get to the 4.63µm pixel size of the 294.

 

I think I am going to start saving my change to get a CMOS camera with the Gpixel GSENSE4040 sensor. 16million 9µm pixels has my imagination running at full speed. SBIG has one, SBIG Aluma AC4040, but it is $12K - $14K depending on the sensor class.

 

Does anyone know if QHY brought their QHY4040 to market and if so at what price? 


Edited by MikiSJ, 08 September 2020 - 07:14 PM.


#63 Peregrinatum

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Posted 08 September 2020 - 06:54 PM

How would that be possible?

 

That would be great if true.

for the same OTA, the camera with larger pixels and QE will have a higher photon gathering rate, and hypothetically need less exposure to achieve the same signal


Edited by Peregrinatum, 08 September 2020 - 06:55 PM.


#64 Dean J.

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Posted 08 September 2020 - 07:41 PM

How much less exposure compared to an ASI1600MM?



#65 rockstarbill

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Posted 08 September 2020 - 07:44 PM

... so ZWO would have to order a special batch with a clear micro lens surface instead of the Bayer matrix?


Well Sony would need to sell a monochrome version of the sensor without a bayer array on it. That's the same for all mono cameras.

#66 Peregrinatum

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Posted 08 September 2020 - 07:47 PM

How much less exposure compared to an ASI1600MM?

about 2.6x, search 'etendue' on here for the backstory... the difference would be the ratio of the pixels squared times the ratio of the QE squared, so roughly:

 

(4.6/3.8)^2 x (0.80/0.60)^2 ~ 2.6x


Edited by Peregrinatum, 08 September 2020 - 07:48 PM.


#67 Dean J.

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Posted 08 September 2020 - 08:06 PM

Well Sony would need to sell a monochrome version of the sensor without a bayer array on it. That's the same for all mono cameras.

True, but do they?  If they haven’t been then this must be something new.



#68 Dean J.

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Posted 08 September 2020 - 08:14 PM

about 2.6x, search 'etendue' on here for the backstory... the difference would be the ratio of the pixels squared times the ratio of the QE squared, so roughly:

 

(4.6/3.8)^2 x (0.80/0.60)^2 ~ 2.6x

And where does the camera’s read noise factor in here?  Don’t you also need to consider the read noise?  I would think that you would want to want to expose sufficiently long to have the sky background (where there is sky background) adequately swamp the camera’s read noise.

 

Do we know the read noise of this detector when binned?


Edited by Dean J., 08 September 2020 - 08:25 PM.


#69 Scott Mitchell

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Posted 08 September 2020 - 08:36 PM

Well Sony would need to sell a monochrome version of the sensor without a bayer array on it. That's the same for all mono cameras.

 

 

True, but do they?  If they haven’t been then this must be something new.

The link provided earlier in the thread shows that Sony is offering this as a mono chip:

https://www.sony-sem...J_LQJ_Flyer.pdf


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#70 rockstarbill

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Posted 08 September 2020 - 08:53 PM

The link provided earlier in the thread shows that Sony is offering this as a mono chip:
https://www.sony-sem...J_LQJ_Flyer.pdf


Thanks. I checked ZWO Facebook and they said it's the 492. So as others stated they seem to be binning the chip to match the pixel size.

#71 Peregrinatum

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Posted 08 September 2020 - 09:37 PM

And where does the camera’s read noise factor in here?  Don’t you also need to consider the read noise?  I would think that you would want to want to expose sufficiently long to have the sky background (where there is sky background) adequately swamp the camera’s read noise.

 

Do we know the read noise of this detector when binned?

RN is a factor for sure with exp, but the ASI1600MM has 10 year old chip technology, so I assume the IMX492 will have better technology and lower RN... but I could be wrong Lol



#72 ezwheels

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Posted 08 September 2020 - 10:16 PM

Most camera drivers allow for binning so it should be trivial to bin 2x2 to get to the 4.63µm pixel size of the 294.

 

I think I am going to start saving my change to get a CMOS camera with the Gpixel GSENSE4040 sensor. 16million 9µm pixels has my imagination running at full speed. SBIG has one, SBIG Aluma AC4040, but it is $12K - $14K depending on the sensor class.

 

Does anyone know if QHY brought their QHY4040 to market and if so at what price? 

I may be out of the loop on this but, have you seen any good reviews of this camera chip? Or even good images produced with it yet? 



#73 andysea

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Posted 08 September 2020 - 11:42 PM

I meant to do this earlier but I didn't get a chance until now. 

I ran the camera through the sensor analysis tool in SharpCap. Here are the screenshots. 

Attached Thumbnails

  • Screenshot (1).jpg
  • Screenshot (2).jpg

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#74 khursh

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Posted 09 September 2020 - 12:06 AM

121=magic number. 



#75 andysea

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Posted 09 September 2020 - 12:09 AM

121=magic number.

For sure, I think it's actually 120 according to ZWO.




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