Extra parameters for capture

[Wolfyann]

Hi, I make tests with a modest fisheye camera based on the OC5647 sensor, the results are difficult when the dark is complete (without Moon, or low light pollution).

1. binning
   I noticed that the 2x2 binning does not give better results, or even worse, but maybe it is due to the camera control register (0x3820 and 0x3821 == 1) which would be different than the RPiHD. However, the result size matches well. Another curiosity, the maximum exposure time which is given as 6 seconds, can be increased to 27 seconds 1x1, unfortunately not more ...

2. night mode
   the night mode gain and auto exposure works well (as it can), but quickly the average collapses and when the exposure reaches the max (27") and the gain at the max (16, but I think the effect is the same from 9). I couldn't find the manufacturer's values in the datasheet.
   The sensor have a night mode (I don't know if it exist on RpiHD dur their QE ), it can be activated by the register 0x3A00 to 1 and set by 0x3A02-05. Unfortunatly this extra parameter seem not to be usable in capture program ? May be another solution to stack to have a kind of long time exposure equivalence with a low cost camera ?

3. Defect pixel cancellation
   the register DFC at adress 0x5000 permit an automatic dead pixels cancellation (not hot pixels !) but I don't find the extra parameter to use this (bit 0 and 1 to high to activate). I've some on mine, and very similar to stars.

I don't know if it possible, may be if I'm not alone to use this sensor, but it'ld permit to use more cheaper camera. I don't have the tool chain to try some software modification, without any answer maybe I'll try to do this waiting to find a better sensor.
The RPiHD has increased a lot recently (like the RPi cards). But all your comments and advice are welcome :)
YD

[EricClaeys]

@Wolfyann Some CMOS cameras implement binning by averaging the pixels, rather than adding them, so binning doesn't increase brightness like it does on CCD chips. The OC5647 may be one of them.

Allsky uses libcamera-still to take pictures, so Allsky has no access to any registers. Did you use libcamera-still during your testing?

The RPi HQ camera has a maximum of 230 seconds, Older RPi cameras had very short maximum exposures and aren't really appropriate for an allsky camera used at night.

Try creating an Issue at the libcamera Git page. That's the team that supports libcamera; I believe their intention is to support multiple cameras, not just RPi HQ. Ask them about OC5647 chips.

[Wolfyann]

Ok, I understand thanks again :)
I've experienced some problems with libcamera-still (it don't work), but I'll investigate between the time I'll find/buy a new sensor.