What shutter speed for 1080P Slow Motion?
- Thread starter Indyreel
- Start date
awelgraven
Well-known member
Are you using Twixtor or some such software? Slow Motion plugins like to have higher shutter speeds to work with because there's less image blur, and thus, it's easier for the software to work.
When using 720 60 I thought the best setting was a shutter of 120. That being the case, wouldn't there be a higher setting for 24?
Barry_Green
Moderator
If you're using the variable frame rate for 80% slow-mo, use 1/60th and that will give you 1080/30p.
If you're wanting to go slower than that and are using 1080/60i and intend to de-interlace it in post for a simulated 60fps, use 1/120th.
If you're using 720/60p as 60fps slow-mo, use 1/120.
If you're wanting to go slower than that and are using 1080/60i and intend to de-interlace it in post for a simulated 60fps, use 1/120th.
If you're using 720/60p as 60fps slow-mo, use 1/120.
stoneinapond
Veteran
What does that achieve that using a "slow down function" in an NLE doesn't?
Barry I'm a bit confused.
I'm using an unhacked GH1 Shooting in FHD 1080/24P . I then transcode it to 24 via Cineform. Can you tell me what shutter speed to use in this case? Thanks
Barry_Green
Moderator
Smooth picture-perfect frame-accurate slow-mo.
Barry_Green
Moderator
Yep, my bad, I was thinking GH2.
Barry_Green
Moderator
For slow-mo? Don't. Switch to 720/60p for slow-mo, and use 1/120th.
thx Barry, gonna try with 720/60p for slow mo using Trixtor. Tried GH2's 80% variable speed and it wasn't slow enough for me.
btw when I attach my Marshall LCD via HDMI, shooting in manual mode, the GH2 Rec Mode option (so you can choose 1080 or 720) is grayed out and you can't select it. I guess you can only shoot 720 WITHOUT an HDMI monitor attached?
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Barry_Green
Moderator
Choose SH mode instead of FHD.
Barry,
After I shoot this footage (like my 1080P footage) can I transcode this 720/60p Slo-Mo footage to Cineform HD 24p? As I am editing this with the 1080p footage.
Also, can I switch (back and forth) from FHD and SH mode while filming, without messing the footage up?
Thanks
After I shoot this footage (like my 1080P footage) can I transcode this 720/60p Slo-Mo footage to Cineform HD 24p? As I am editing this with the 1080p footage.
Also, can I switch (back and forth) from FHD and SH mode while filming, without messing the footage up?
Thanks
Ok guys, read the following article about shutter angle, which is the relationship between optimum shutter speed and frame rate: blog.tylerginter.com/?p=385
I think the article's picture of a vintage Bolex 16mm film camera is a good indication of the dated perspective of its information. Actually, one of the statements he makes is incorrect. It was not "mechanically impossible" for film camera shutters to exceed 180-degrees and some of them actually did so. To my eyes, shutter speeds between 1/40 - 1/60 second produce a natural appearance of motion blur, regardless of frame rate. Since the Bolex ran at 24fps, its 180-degree shutter produced a 1/48 second shutter speed which looks quite pleasing.
The exception to setting shutter speed is when shooting at 50p or 60p for a slow-motion effect. As Barry explained earlier, you'd use a 1/120 second shutter for shooting at 720p60 with the intent of slowing it down to 24fps. At 24p, the 1/120 second shutter would effectively become 1/48, blending naturally with the normal-speed footage.
Applying the "180-degree shutter rule" to shooting normal-speed footage at 720p60 would dictate a 1/120 second shutter. To my eyes, that produces an effect that is lacking in motion blur and looks too choppy. I much prefer shooting at 1/60 second shutter speed in general, as it also avoids the hazard of strobing effects from 60hz lighting (in the USA). Similar considerations would apply to Europe and regions which use 50hz lighting.
Here's a link to a clip which graphically shows the motion blur effect of various shutter speeds:
http://vimeo.com/5249682