SOLVED CS-MIPI_IMX307 best settings to capture stars?

MK

Hi,
could you advice what best settings to use to capture stars with the cs-mipi-IMX307. I use now version 2.36 firmware of the camera with a 4mm lens. I used now slow shutter mode, but not clear how to set the exposure times and gains etc.

I want to capture video h264, on 1920p with 25fps

or

video h264, on 720p with 60fps.

Video will be used to capture meteors in a global network.

Many thanks in advance for your advice.
MK.

veye_xumm

@mk
Hi,
I think the slow shutter mode is conflict with framerate (1080p@25 or 720p@60fps). I mean the framerate will drop once the camera work in slow shutter mode.

As for the slow shutter mechanism, please refer to part5: http://wiki.veye.cc/index.php/CS_Camera_Slow_Shutter_manual#Autoexposure_mode_slow_shutter_configuration

My suggestion:
0. Use Autoexposure mode.

Set a proper slowshuttergain first，make sure the noise is acceptable in your most dark environment.
Set a proper max exptime, make sure the framerate drop is acceptable. So that you can have a smooth video.

If you want 25fps at least in 1080p mode and 60fps in 720p mode, I think you can't use slowshutter mode.

MK

Hello, thank you for your advice. A few more questions:

Is it possible to go for 720p@25fps in slowshutter mode?
1a. Is it possible to set the framerate to a fixed value like 25fps in 720p and slowshutter mode?
How to get a return of the set framerate during capturing/streaming?
How to set the exposure time to a fix value, like 40000us for 25fps, with the autoexposure mode as you advice?
To maintain a fixed framerate is important. If better not to use slowshutter mode, due to the variable (dropping) framerate, wich settings to be used best to reduce the noise in the dark enviroment?
(Manual settings are preferred to keep a steady videostream. With manual settings I could not figure out to reduce the noise)

Many thanks in advance,
MK

veye_xumm

@mk

@mk said in CS-MIPI_IMX307 best settings to capture stars?:

Hello, thank you for your advice. A few more questions:

Is it possible to go for 720p@25fps in slowshutter mode?
yes, of course.
1a. Is it possible to set the framerate to a fixed value like 25fps in 720p and slowshutter mode?
Of course, you do not need set slow shutter mode. Just need set the stream mode will get a fix framerate.

./cs_mipi_i2c.sh -w -f videofmt -p1 1280 -p2 720 -p3 25

And you can set the exposure time rang by:

./cs_mipi_i2c.sh -w -f aetime -p1 XXX

range:(100,1/framerate]

How to get a return of the set framerate during capturing/streaming?

./cs_mipi_i2c.sh -r -f videofmt

How to set the exposure time to a fix value, like 40000us for 25fps, with the autoexposure mode as you advice?

use manual exposure mode and set metime.

To maintain a fixed framerate is important. If better not to use slowshutter mode, due to the variable (dropping) framerate, wich settings to be used best to reduce the noise in the dark enviroment?
(Manual settings are preferred to keep a steady videostream. With manual settings I could not figure out to reduce the noise)

I think you can try this: do not use slow shutter mode, just decrease the framerate as you need.

./cs_mipi_i2c.sh -w -f videofmt -p1 1920 -p2 1080 -p3 [frame_rate_you_want]

MK

Hello, many thanks for your reply, most welcome!

i will use manual exposure time and a and d gain.

I saw in the manual at 3.8 ispcap
When I read Ispcap I get return 0X17

Can you explain function of Ispcap?
Can I write new settings to Ispcap?

Can you explain a bit more what the A gain function will do?

Can you explain a bit more what the D gain function will do?

Thanks in advance!!

veye_xumm

@mk

@mk said in CS-MIPI_IMX307 best settings to capture stars?:

Hello, many thanks for your reply, most welcome!

i will use manual exposure time and a and d gain.

Can you explain function of Ispcap?
I have add explaination for that.

Can I write new settings to Ispcap?
No, It is read only.

Can you explain a bit more what the A gain function will do?
Can you explain a bit more what the D gain function will do?

Again ：Analog gain
Dgain : Digital gain
The amplification of the signal will introduce some noise.

Thanks in advance!!

MK

Thanks,
To see mag 5 stars with the IMX307, Bortle scale at location 5:
Black and White mode
Manual capture
1080p/25fps
A gain 10
D gain 22

veye_xumm

@mk
Dgain will introduce obvious noise. I suggest you reduce the value of dgain as much as possible.

IMX307,again range is[0,27]dB, step 0.3dB.
IMX307,dgain range is[0,42]dB, step 0.3dB.

@mk said in CS-MIPI_IMX307 best settings to capture stars?:

A gain 10
D gain 22

Why not use Again 27,and Dgain 5?

MK

Why not use Again 27,and Dgain 5?

Thanks I will try and let you know.