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.
âShutter Priorityâ is the reverse mode in which you set the shutter speed and the f-stop is set automatically. So, lens speed refers to the maximum apertureâor f-stopâto which your camera lens can open up, and the âfasterâ the f-stop, the easier it is to shoot under low light and freeze fast-moving subjects.