HTC One M8 for Windows - Manual (Page 127)

Crop Wide
Zooming Zoom slider should be at the minimum zoom level.
Continuous shooting Not supported
Lighting
§ Use Duo Camera in an environment where there is a good light
source. Post-processing effects for Duo Camera do not work for
low light photography or when you're using the camera flash.
§ If lighting is uneven, like when the background is a little bit under or
overexposed, tap
to adjust the exposure settings.
§ Hold HTC One so that you don't block the second camera lens.
Camera 127