GH5 GH5: why two buttons to shoot?

[FoxAdriano]

Two questions please, I need to understand better since I've always used only videocameras for many years. Is it better to film at 400 ISO or put 200 ISO on a full sun day in the African sun?

In the GH5 there are 2 buttons: in the instructions, a button called 'shutter button' and the other 'video button' (I don't have english manual). Can you tell me the difference? I make only videos with my GH5 and I have always used the button 'shutter button' because it is much more comfortable. The other one is terribly uncomfortable. In other words, I use the "shutter button" to shoot. It is a lot more comfortable, also because it sets focus before shooting when I click half button.
I would be curious to know if I have done everything wrong until today.
I attach the image. The buttons in question are numbers 11 and 9.
Thanks

 

[-griffy-]

For ISO, you typically want to use the lowest possible given the situation. Less light will typically call for a higher ISO, so a bright sunny day 200 would be better.

The reason there are two buttons that will record is because it's a hybrid stills/video camera. If you are in a photo shooting mode, the shutter button will take a picture, but you can still use the video button to record a video. In a video mode, both buttons will record video.