Effect of shutter speed on look of video?
- Thread starter sbryan
- Start date
HorseFilms
Look ma no hands
Not generally. One of the few times you'll see it happen is when shooting under crappy fluorescent lighting. You sometimes see color shifting with the shutter at some speeds in those conditions.
khmuse
Tech Guru
Shutter speed has an effect on two properties.
First, the period that the shutter is open effects the quantity to light gathered. The longer the shutter is open, the more light reaches the imagers. The relationship is a linear one. Double the period and you double the light, half the period and you half the light.
Second, the period that the shutter is open effects relative motion blur. For objects which move in relationship to the camera frame (either by moving themselves or by the camera moving in relationship to their position in the frame) blur can and does occur (sometimes obvious, sometimes nearly imperceptibly). The longer the shutter is open, the more blur that an object in relative motion will impart. The shorter the period the less blur.
Film, unlike video can have different reciprocity curves for each of the color layers and can exhibit a color shift with very long exposures, video, in general lacks this effect.
First, the period that the shutter is open effects the quantity to light gathered. The longer the shutter is open, the more light reaches the imagers. The relationship is a linear one. Double the period and you double the light, half the period and you half the light.
Second, the period that the shutter is open effects relative motion blur. For objects which move in relationship to the camera frame (either by moving themselves or by the camera moving in relationship to their position in the frame) blur can and does occur (sometimes obvious, sometimes nearly imperceptibly). The longer the shutter is open, the more blur that an object in relative motion will impart. The shorter the period the less blur.
Film, unlike video can have different reciprocity curves for each of the color layers and can exhibit a color shift with very long exposures, video, in general lacks this effect.
Keep in mind, though, that on a video camera, there's no shutter. It's always "open." What "shutter speed" refers to is the fraction of a second that the camera reads the CCD(s), which is analogous to the amount of time a shutter lets light through on a film camera.
khmuse
Tech Guru
The actual term is acquisition period (there are also transfer and clear parts of the CCD cycle) but the analogy of a film camera is likely a simpler concept for most to grasp.
Each of the CCD receptors accumulate photons during the acquisition period. This results in a potential difference accumulating between each receptor and the substrate of the device. During the transfered cycle the net accumulated charge is read by the quantizer and is assigned a value according to the accumulated charge Voltage. During the final cycle, the CCD receptor is cleared by the application of a low impedance device (typically a MOS-FET) between each point and the substrate.
Each of the CCD receptors accumulate photons during the acquisition period. This results in a potential difference accumulating between each receptor and the substrate of the device. During the transfered cycle the net accumulated charge is read by the quantizer and is assigned a value according to the accumulated charge Voltage. During the final cycle, the CCD receptor is cleared by the application of a low impedance device (typically a MOS-FET) between each point and the substrate.
I just don't want anyone thinking their camera has a shutter. One time, someone asked if the "clunk" was their shutter coming loose. 
HorseFilms
Look ma no hands
khmuse said:
There was one in the HVX technical section last week and everyone gave him true information. 'Twas a sad day.
