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).
A fast shutter speed such as 1/400th of a second will produce a series of crisp frames that have a choppy look when played back. A slow shutter speed such as 1/30th of a second, on the other hand, will produce a series of slightly blurred frames that have a smoother look when played back.
Camera aperture and shutter-speed controls are calculated so that an increase of one f/number compensates for a one-step decrease in shutter speed. For example, 1/250 at f/8 is equ*alent to 1/125 at f/11. The table below shows how aperture and shutterspeed are interrelated. All the combinations give the same exposure.