Ideally, a hydrogen fuel-cell vehicle has no environmental impact. Energy is produced by combining hydrogen with oxygen pulled from the atmosphere, and the tailpipe emission is water. The hydrogen fuel could come from a number of sources (Iceland recently started pulling it out of the ground).
4) Fast, Slow and Long Shutter Speeds. Fast shutter speed is typically whatever it takes to freeze action. For me, it is typically above 1/500th of a second for general photography and above 1/1000th of a second for bird photography. NIKON D700 @ 420mm, ISO 450, 1/2000, f/5.6.
When you shoot in â Aperture Priority â mode, you set the lens aperture, while the camera automatically sets the shutter speed. There are two ways to manually set the shutter speed: a) By setting the camera to â Shutter Priority â mode, where you set the shutter speed and the camera automatically selects the aperture. b) By setting the camera to â Manual â mode, where you set both shutter speed and aperture manually.