On an EX3, what’s best for indoor shots of lectures etc?
- Normally film runs at 24fps, with a 180° shutter – which is 1/48th second.
- Hence for 25 fps, ideally use 1/50 second, or nearest available match to this.
- Uncertainty: For 50i, each field is at 25fps, so presumably still use 1/50 second ? Depends on how camera works?
- For a shot of someone talking, it would be hard to see the difference between a 1/48th shutter time and a 1/60th shutter time.
- To avoid (conventional) light flicker, frame rate should divide by integer into twice the power frequency.
- EX3 has no 1/50 shutter speed, at least when specified by Time – nearest equivalent is 1/60. This may risk some degree of light-flickering in 50Hz mains countries.
- For 1080i50
- Initially, used “No Shutter”, to maximize exposure with least Gain. But gave noticeable motion-blur.
- For 50p or 25p
- 1/50 or nearest equivalent (on EX3 is 1/60)
- For 50i, opinions vary:
- UseEX3’s nearest equivalent time-based shutter time of 1/60
- Use 180 degrees (assumes this angle relates to frames-per-second, namely 25fps for each frame – but is this valid when interlaced)
- Use No-Shutter (assumes 50i shoots each field alternately, at 50fps, hence no-shutter is inherently 1/50 – but is that assumption true?)
Discussion:
- http://reduser.net/forum/showthread.php?t=32073
- what is the normal shutter speed for feature movies?
- Normally film runs at 24fps, with a 180° shutter – which would indeed be 1/48th second
- …a 1/48″ exposure most accurately replicates the human eye’s perception of the phenomenon known as “persistence of vision” and therefore provides the most natural-looking reproduction of normal movement.
- To avoid light-strobing effects (at least for conventional lights…):
- The formula is any frame rate that divides evenly into twice the power frequency is safe. 1, 2, 3, 4, 5, 6, 8, 10, 15, 20, 24, 30, 40, 60, 120 fps for 60 Hz.
- For 60 Hz countries, you would get the following flicker free frame rates:
- 120/1 = 120,
- 120/2 = 60,
- 120/3 = 40,
- 120/4 = 30,
- 120/5 = 24,
- 120/6 = 20,
- 120/7 = 17.143, …
- And, for 50 Hz countries you will get:
- 100/1 = 100,
- 100/2 = 50,
- 100/3 = 33.33,
- 100/4 = 25,
- 100/5 = 20,
- 100/6 =16.67, …
- http://www.dvinfo.net/forum/sony-xdcam-ex-cinealta/141178-music-video-720-50p.html
- 720p25 or 720p50: 1/50
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- 50P with a shutter of 1/100 converted to 25P would be jerky if the editing system takes out every second picture ( to make it 25P)
- “I have tried using the camera in 720 50p with a 180 degree shutter angle at 1/100 shutter speed as this is the recommended setting for progressive shooting. The problem is the motion I get with this setting seems jerky.”
- http://www.cybercollege.com/tvp019.htm
- “When (video recording) under fluorescent lights (in US), it’s advisable to stick to a 60th second (normal) shutter speed. Using a faster shutter speed typically results in a flickering effect in the video as the chip exposure interval interacts with the normal flicker of fluorescent lights.”
- My reaction:
- Fluorescent lights flicker at twice means frequency.
- In US, mains frequency is 60 Hz, while in Europe (including UK) it is 50Hz.
- Correspondingly, US video framerate is 30fps (approx) and Euro is 25 fps (approx), while film (and some film-like video modes) is approx. 24 fps.
- On EX3, there is no 1/50 option, nearest is 1/60. In Europe, that 1/60 will capture almost-but-not-quite one cycle of mains, corresponding to almost-but-not-quite two cycles of light flickering.
- My reaction:
- “When (video recording) under fluorescent lights (in US), it’s advisable to stick to a 60th second (normal) shutter speed. Using a faster shutter speed typically results in a flickering effect in the video as the chip exposure interval interacts with the normal flicker of fluorescent lights.”
- http://www.dvxuser.com/V6/showthread.php?181124-25p-50p-shutter-speeds
- …as long as you are in the ballpark of the look of a 180 degree shutter, it’s fine because motion blur — which is what we are talking about — is affected by how much movement there is. So for a shot of someone talking, it would be hard to see the difference between a 1/48th shutter time and a 1/60th shutter time, for example.
- 99% of the time I have the shutter at 1/50 in either mode to emulate a 180 degree film shutter. I avoid going below 1/50 as that makes the motion blur to long and smeary for me. Unless I use it as a effect, watch “A Kindling Light” in my sig link. I only use 1/100 in the 720p 50 fps mode if I know for certain that I want to use the take in slow-motion.
- http://www.dvxuser.com/V6/showthread.php?210763-Short-Handheld-Video-with-HPX371e
- Gary Nattrass: “If we both shoot 1920x1080i 25np AVC intra 100 with a shutter of 1/50.0 with the BBC film settings it will be sort of a constant.”
- He tends to know what he’s doing…
- Gary Nattrass: “If we both shoot 1920x1080i 25np AVC intra 100 with a shutter of 1/50.0 with the BBC film settings it will be sort of a constant.”
- http://www.dvinfo.net/forum/sony-xdcam-ex-cinealta/468479-shutter-speed-ex3-pal-system.html
- …there is no 1/50 speed for 50i … I ended up leaving the shutter switched on with 1/60 shutter speed … and it worked out ok.
- just be aware that you might see some flickering if you shoot 1/60s under (50Hz mains) artificial light. Best to switch off the shutter when shooting 50i.
- …best just to leave the shutter off, you shouldn’t need it as there should be no blurring (at) 50 frames per second
- (Naively, but probably not wise, for interlaced) … an angle of 180 degrees would be better than 1/60.
Further Links:
- http://www.mediacollege.com/video/camera/shutter/
- Shows comparative images for a car moving through frame
- http://www.cybercollege.com/tvp019.htm
- Creative use of shutter speed and interaction with exposure (f-stops). Examples of speeding objects.