Camera image is getting darker and darker

[Oliver2526]

Hi everyone,

I use a 5-MP-camera together with two IR-led-lamps to watch my garden in the night. The software that I use is RPi Camera Web interface and everything works perfect at daylight. However, a night light the brightness of the images drops gradually and is almost total black after about 2 hours. As a simple reboot brings the bright image back again, I think it has something to do with the software and not with the IR-lamps which work independently from the software running on the Pi.

I already tried different settings of raspimjpeg (brightness, contrast, exposure mode, fps, ...), but I could the image not stop from getting darker.
Furthermore, I found out that I can trigger this brightness drop manually by flashing a light (e.g. from my smartphone) into the cam. After the flash the brightness doesn't come back to its previous level.

I posted this problem to RPi-Webcam-Interface-thread, but the developer suggested me to re-post the problem here, as he thinks it is somehow related to the MMAL handling of the brightness adjustment (whatever that means).

So, did anyone experienced a similar issue? And what could be a possible solution?

Thanks for any help!
- Oliver