This button is essentially your focus assist button:
On page 3 of the custom menu, you can change its behavior for manual focus from four options:
1) punch in when either rotating the focus ring on the lens OR after pressing the Fn3 button
2) punch in only when rotating the focus ring
3)...
You can get a larger matte box with some barn doors to provide more coverage against lens flares:
but if there's a bright light source shining right down your lens there's always gonna be a risk of flare. Sometimes all it takes is holding your hand out over the lens in a specific spot to get...
Did you guys see the Helix Jr. that Letus showed at NAB?
https://www.youtube.com/watch?v=A1Uwr_sLVBs
I do like the orientation of the device that puts the camera closer to eye-level by default:
Although with the Helix Jr. at "sub-$3000" it looks like the Ronin-M is the more feature complete...
I'm definitely not talking about barrel distortion, but the whole image skewed to one angle. This shot below for example is the most obvious one to me. I've added perfectly vertical lines for illustration. At the start of the pan, it seems like maybe the poles are just at an angle naturally...