SV305 - RAW8 or RAW16 - RAW12 gone?

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Planetibo
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SV305 - RAW8 or RAW16 - RAW12 gone?

#1

Post by Planetibo »

Hello,
I have a SVBONY SV305 Camera.
I recently updated the SVBONY drivers and updated Sharpcap.
Since then, it seems to me that the RAW12 bit depth has disappeared.
Therefore, the Sensor Analysis is now wrong:

Gain Value e/ADU Read Noise (e) Full Well (e) Relative Gain Rel. Gain (db) Dynamic Range (Stops)
0 0,171207648 2,710052859 11220,2644 1 0 12,01549806
50 0,09910628 2,312291785 6495,029152 1,727515634 4,748439727 11,45579682
100 0,055494989 1,241210327 3636,919613 3,085101018 9,785387781 11,51675372
150 0,030951818 1,116110407 2028,458333 5,531424638 14,85674 10,82768821
200 0,017674932 1,010928227 1158,344346 9,6864671 19,72330815 10,1621679
250 0,009956643 0,959338787 652,5185353 17,19531905 24,70820477 9,409762781
300 0,005558575 0,913468049 364,2867686 30,80063666 29,77119387 8,639504612
350 0,003201264 0,879540124 209,798012 53,48127131 34,56403445 7,898035897
400 0,001808931 0,879264981 118,550092 94,64576712 39,52202391 7,074983057
450 0,001012015 0,876914174 66,32341841 169,1750014 44,56672377 6,240938908
500 0,000604952 0,900492762 39,64613501 283,0102959 49,03604471 5,460321738


Whereas before, the values seemed normal:

Gain Value e/ADU Read Noise (e) Full Well (e) Relative Gain Rel. Gain (db) Dynamic Range (Stops)
0 2,227735813 2,543144587 9124,80589 1 0 11,80896467
50 1,273301534 2,100621477 5215,443083 1,749574436 4,858648487 11,27775789
100 0,718757977 1,119770203 2944,032675 3,099424123 9,825620176 11,36037527
150 0,399449239 1,067226169 1636,144084 5,577018539 14,92804176 10,58221814
200 0,227896985 0,977408868 933,4660504 9,775187738 19,80250214 9,899419644
250 0,127731965 0,91207337 523,1901276 17,44070732 24,83128188 9,163969718
300 0,072033433 0,876003066 295,0489419 30,92641455 29,80659146 8,39580265
350 0,039985476 0,81685735 163,7805109 55,71362452 34,91922826 7,647463819
400 0,023070084 0,831602642 94,49506215 96,56383817 39,69629039 6,828200791
450 0,012944994 0,829001391 53,02269662 172,0924523 44,71523647 5,999091711
500 0,007385426 0,81000523 30,25070551 301,6394407 49,58976254 5,222893755

I tried to check the option in the parameters "Record in 8/10/12 bits without mapping to 16 bits"
I want to do photometry, so I need fair values.
Does anyone have any idea what's going on?
Thanks in advance
Planetibo
Posts: 7
Joined: Tue Dec 01, 2020 7:42 am

Re: SV305 - RAW8 or RAW16 - RAW12 gone?

#2

Post by Planetibo »

I have just tested the downgrade with each version containing the mention "upgrad SDK SVBONY" and it appears that with the following version, I find the RAW12 mode:

SharpCapInstall-4.0.8185.0.exe

After this version no more RAW12, it turns into RAW16.

How can we notify the developer?
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Re: SV305 - RAW8 or RAW16 - RAW12 gone?

#3

Post by admin »

Hi,

the fact that it shows RAW16 instead of RAW12 isn't a massive issue - it should just mean that the data comes to SharpCap already in 16 bit form rather than in 12 bit form and SharpCap does the bitshift to 16 bits internally (which was what used to happen). It will affect the photometry option that you mention, since SharpCap now doesn't know for sure the true bit depth of the sensor. That will mean that you will probably need to rescale the images down to 12 bit data using some external application :(

As to the sensor analysis, that will work even with the new SDK showing the camera at RAW16 and will detect the camera as being 12 bit (I just tested it). What will confuse it though is if any of the image processing controls are set to anything other than their defaults. These controls (and default values) are:

Contrast : 50
Gamma : 1.00
Saturation & Sharpness : 0
White balance R/G/B : 128

Changing those controls applies digital manipulations in the SDK before the image gets to SharpCap and messes up the bit depth measurement because the pixel values will no longer be a multiple of 16.

cheers,

Robin
Planetibo
Posts: 7
Joined: Tue Dec 01, 2020 7:42 am

Re: SV305 - RAW8 or RAW16 - RAW12 gone?

#4

Post by Planetibo »

Sensor Analysis does not seem to detect the 12 bits bit depth in 4.0.8365:
Image


Whereas with version 4.0.8185 it was in 12 bits with a coherent e/ADU:
Image


Another question: How can I find the precise Unity Gain (1 e/ADU) to have the Unitay Gain?
Seems to be gain 125, but not shure.
Planetibo
Posts: 7
Joined: Tue Dec 01, 2020 7:42 am

Re: SV305 - RAW8 or RAW16 - RAW12 gone?

#5

Post by Planetibo »

Here is a result of Pixinsight's BasicCCDParameters script.
I used Sharpcap 4.0.8395 with the settings below.

It seems that the gain 110 is the closest to reach the 1e / ADU.

Image
Image
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Re: SV305 - RAW8 or RAW16 - RAW12 gone?

#6

Post by admin »

Hi,

since the new change from the SDK, you need to set the white balance values to 128/128/128 for the sensor analysis to work I think.

Previously the data came from the SDK at 12 bits (0..4095), which SharpCap would multiply by 16, leading to values from 0..65520 (all the values being multiples of 16). Even if the colour balance was set to non default values (you have 100/100/100), the sensor analysis would detect the 12 bit bit depth. Note that although the bit depth would be correct with non default colour balance, other measurements may be affected.

Now the data comes from the SDK at 16 bits. If all the white balance/contrast/sharpness etc are default then all the pixel values will be multiples of 16 and the 12 bit depth of the sensor will be detected correctly. If the WB values are not 128 or other things like contrast have been adjusted then the pixel values will have no pattern and the sensor analysis thinks the camera is 16 bit.

I will put some code in the sensor analysis to force the appropriate controls (WB, contrast, etc) to their default values when running an analysis on an SVB camera, which will restore correct results.

cheers,

Robin
Planetibo
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Re: SV305 - RAW8 or RAW16 - RAW12 gone?

#7

Post by Planetibo »

Thanks Robin!
How can i set or reset the all default values?
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Re: SV305 - RAW8 or RAW16 - RAW12 gone?

#8

Post by admin »

Hi,

hold down the CTRL key while opening the camera - that should set things back to defaults - see https://docs.sharpcap.co.uk/4.0/#Keyboard%20Shortcuts

cheers,

Robin
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