Facial twitch: I believe these twitches are similar to the twitches people get in their eyelids. Usually it goes away within 6 weeks or so. There are other causes such as caffeine, stress, alcohol, electrolyte imbalances and excessive fatigue. Feel better.
A shutter speed of 1/30 for example will let in twice as much light as a speed of 1/60 since it is two times slower. When you decrease the shutter speed by a factor of two you are increasing the amount of light by one stop. Remember that fractions get larger as the number on the bottom gets smaller.
Different combinations of shutter speed and aperture used to achieve the same exposure. Shutter speed: Speeds faster than one second are shown as fractions (e.g.: â¦1/125, 1/160, 1/200, 1/250â¦). Some cameras may omit the numerator so that â1/125â becomes â125,â â1/250â becomes â250,â etc.