All reflexes allow the use of the B (bulb) pose which allows the use of very long times (seconds, minutes or hours), the B pose is useful in photographic genres such as night photography. When setting the B exposure the shutter is opened when the shutter button is pressed and is closed when the button is released.
There is also the T pose that works in a similar way, pressing the button starts the exposure and pressing it again ends, in both in cases you risk moving the camera, so it is advisable to use the remote control or the self-timer. Besides these that you can have shown you the cameras allow to use also intermediate fractions for which you can have for example also a time of 1/200 and of 1/800.
The shutter speeds are divided into slow and fast, you can define the lenses longer than 1/60, the shortest times are short 1/60, everything depends on the focal length, the speed of the subject photographed and the distance separates from it, with a telephoto lens generally 1/60 is considered a slow time and you will have photos moved if the subject is in motion, while with a wide angle pushed 1/60 it can go well to freeze the movement as part of Digital Imaging Los Angeles.
If you have to photograph a static subject and you can’t raise the ISO or change the aperture, the only thing is to use long times and avoidndo the blur generated by the vibrations of the hand with the aid of a tripod.
The right amount of light is given by a certain combination of time and diaphragm, corresponding to a certain exposure value. EV exposure values indicate the brightness of the subject framed by a number scale, the table above shows the time-aperture combinations and the related EV value.
EV (exposition value)
EV (exposition value) stands for exposure value, is related to the brightness of the scene and to the ISO sensitivity of the sensor, in summary the EVs can be considered the unit of measurement of light linked to Digital Imaging Los Angeles.
When the light changes by an EV to compensate, it is enough to move a time or a diaphragm, so if the light increases by an EV it means that to get the correct light intensity to the sensor just close a diaphragm or set a faster time and the other way around. But the time and the aperture do not change only according to the intensity of the light but also based on the ISO sensitivity set.
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