0:00 as i'm sure you know moving images
0:03 are created with multiple still images
0:07 exactly how many still images or frames
0:10 are taken in the camera
0:12 is known as frames per second
0:15 the usual number of frames per second
0:17 for films is around 24 or 25
0:20 fewer frames than this would appear
0:22 jittery and movements wouldn't look as
0:24 smooth as they should
0:27 more frames than this would simply mean
0:28 you would be getting more images
0:30 captured in one second
0:32 and therefore give clearer more defined
0:34 movements
0:37 high frame rates can also be used to
0:40 slow the footage down
0:41 in the edit if you captured 24 frames
0:45 per second in camera
0:47 and slowed this down to play back over
0:49 two seconds in the edit
0:51 there wouldn't be enough frames to make
0:53 the image look natural and smooth in
0:55 playback
0:56 therefore if you plan to slow the
0:58 footage down
1:00 you need to have the appropriate amount
1:01 of frames per second
1:03 captured in camera for example
1:06 if you filmed 100 frames per second and
1:09 spread this out across four seconds in
1:11 the edit
1:12 then the frames per second in playback
1:14 would be twenty five
1:16 doing this would make the footage four
1:18 times slower than watching it in real
1:20 time
1:22 if you filmed ten thousand frames per
1:24 second you would be able to play
1:26 back the footage 400 times slower than
1:28 real time
1:31 the more frames per second you capture
1:33 in camera the slower you can play it
1:35 back in the edit
1:37 however the more frames that are
1:39 captured
1:40 the more light is needed to capture them
1:44 this can be balanced out by adjusting
1:46 the iso
1:47 iris or by simply using bigger lights
1:52 another element to consider is the
1:54 shutter
1:56 when we talk about shutter angles this
1:59 refers to when things are shot on film
2:01 and there is a physical disk as the
2:03 shutter
2:05 the angle of which could be manually
2:06 changed
2:09 some digital cameras do also have a
2:11 physical shutter
2:12 although it is designed differently and
2:14 is more of a rectangle shape
2:18 for most digital video cameras there
2:20 isn't a physical shutter
2:22 it's more of a shutter effect created by
2:24 the camera's sensor
2:26 but the term shutter angle is still used
2:28 to describe the effect
2:29 caused as well as the equally used term
2:33 shutter speed
2:36 shutter angle or speed affects exposure
2:40 and motion blur the angle refers to how
2:43 much of the shutter is open
2:45 and therefore how long one single frame
2:47 is exposed to light for
2:49 when the angle of the shutter is
2:51 decreased
2:52 this reduces the motion blur of a moving
2:55 object because it's captured faster
2:59 however as a result of this the light
3:01 reaching the image will be lessened
3:04 as a general rule you want to have a
3:06 shutter angle of 180 degrees
3:10 this is half the shutter disc and is the
3:12 most common shutter angle to use
3:15 the equivalent of this in shutter speed
3:18 terms
3:19 would be 1 over double the frame rate
3:22 for example if the frame rate is 25
3:26 frames per second
3:27 then the shutter speed will be 1 over
3:30 50.
3:31 this means one fiftieth of a second
3:34 if you increase the frames per second to
3:36 fifty
3:38 then the shutter speed will be one
3:39 hundredth of a second
3:43 the way digital sensors create a shutter
3:46 effect without a real shutter
3:48 is by activating the photo sights on the
3:50 sensor like a switch
3:52 either being on or off this way
3:56 it can simulate the length of time a
3:58 physical shutter would have been
4:00 open for a rolling shutter
4:03 means that the photo sites are activated
4:06 from top to bottom
4:07 or side to side this technique can
4:10 sometimes give
4:11 unusual effects like the jello effect
4:16 on the other hand the newer global
4:18 shutter doesn't have this problem
4:20 because all of the photo sites are
4:22 switched on at the same time
4:24 this way the motion blur can still be
4:26 regulated but you don't get any
4:28 distortion as a side effect
4:32 the sensor needs to convert light into
4:35 digital information
4:38 this can either be achieved with a ccd
4:40 sensor
4:41 or a cmos sensor ccd
4:44 sensors work by sending the charge from
4:47 the photo sites
4:48 one row at a time and takes them to a
4:50 chip elsewhere to be converted into
4:52 information
4:54 cmos sensors are designed differently
4:58 instead of converting information
4:59 elsewhere in rows
5:01 each photo site has its own tiny
5:03 converter next to it on the sensor
5:06 the downside to this is that more noise
5:09 is accumulated on the image because of
5:10 this
5:12 however it is the cheaper sensor
5:14 designed to have
5:16 on the other hand ccd sensors are more
5:18 expensive
5:19 but create higher quality low noise
5:22 images
5:26 thanks for watching like this video if
5:29 you found it useful
5:30 and we'll see you next time
5:43 [Music]
5:50 you
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