Mk809iii and webcam logitech dark topic

Hi everybody
I have an android stick mk809iii and I want to use it with skype
I have a webcam logitech c270 which I have heard is fully compatible with such devices, but I found out that the the image is too dark, almost -2 stop exposure

In the camera app I can increase sensitivity in order to see the image, but in skype I can't.... Is there any tweak to solve this problem?