Hello friends! I am a new filmmaker and hoping someone could offer some advice on this issue I'm having. I'm still confused on how to maintain proper light exposure while filming outdoors for projects such as documentaries. I can generally get the arrow of the light meter in the middle but as soon as I move I'm either way underexposed or vise versa. In "run and gun" situations how do you have continuous shots without having to constantly adjust the aperture of the lens? As soon as I change direction or even zoom in the light exposure changes pretty dramatically. How do you make this less of a headache when constantly having to move around, and not have to record the actual compensation on footage you want to keep? Maybe I'm over thinking this but its something that's causing a lot of stress for me while out filming. I currently am using the canon c100 mark ii. I'm sure this is a rookie question but I'm new so be easy on me. :)
I have that same camera and when I'm in constantly changing light situations, I take it off manual and use Canon's automatic iris. It definitely does a better job than I could especially when panning across a big scene. You will have to pan a little more slowly than usual to allow the camera time to adjust the exposure, but it works. You can also keep pushing the "auto iris" button on the side of the camera as you notice the waveform getting too hot or too dark.
I believe that the only way to really do it manually is to spend a few years working with really old guys who have honed their skills over 40 or 50 years and learn their secrets so that you too can look at any scene and know exactly when to change your iris and by how much.