Slow motion mode on Mini 4 Pro question

[floyd]

If using the slow motion mode at 100 fps is it recommended to have the shutter speed set to 1/200 of a second? Or does that rule not apply since DJI has integrated slow motion video into the drone? Do you know what percentage DJI has slowed the speed to? 25% 50% 75%? Does the video quality suffer if slowing the footage down even more in post? Thanks!

 

[Droning on and on...]

I don't see why the rule wouldn't apply... the only thing "special" about slomo is it writes 30fps into the metadata, so it'll playback at 30fps, slowing by about a factor of 3.

 

[mavic53]

Works well I just selected slo motion in the menu did not alter shutter

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[floyd]

Works well I just selected slo motion in the menu did not alter shutter

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Yeah, that looks super smooth. Do you happen to recall your settings? FPS? Shutter speed? Resolution?

 

[mavic53]

4K never changed shutter speed otherwise all in auto

 

[Feek]

Works well I just selected slo motion in the menu did not alter shutter

Nice, what captured the sound?

 

[mavic53]

It is a recording of a steam engine going over the viaduct but not that actual one. Sorry.

 

[mavic53]

Screen shot showing settings

 

[a2tomm]

Works well I just selected slo motion in the menu did not alter shutter

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WOWZERS WAY NICE EXAMPLE OF SLOMO ,I have yet to try it

 

[Droning on and on...]

Side question for the braintrust: Watching the video in post #3, it got me wondering: why does the smoke from the boiler pulse? I understand the pulsing inherent in the steam drive, cylinders, etc., but isn't the output of the smokestack just the exhaust from burning wood/coal/oil?

 

[IFlied]

Copied from somewhere on the web:

“The exhaust from the cylinders is pushed through the smoke stack to create a draft in the fire box. That way the fire burns better.”

Saw this several places, so didn’t give credit . . .

 

[Droning on and on...]

Oh, now that's cool! Them durn clevah yoomans!

Thanks @IFlied!

 

[floyd]

Probably a foolish question, but here goes...

All other parameters equal and filming at 4K, generally speaking, which will yield better slow-motion results with the Mini 4 Pro?
A. Drone set at 30fps, using the slow-motion setting on the Mini 4 Pro, and auto exposure
B. Using the 180º rule (30fps and 1/60 shutter speed and ND filter if necessary) then editing in post?
C. There would be little to no difference in video quality

 

[Droning on and on...]

@floyd, I'm not understanding what you wrote.

You can't set the video to 30fps and then film in slomo. When you select slomo on the M4P, it captures at 120fps.

AFAIK, there's nothing special about slomo other than writing 30fps in the metadata so that it plays back at 30fps, creating the slow motion effect.

So the same "rules" apply... use a shutter speed setting 1/2× the frame rate, or 1/240s.

 

[akdrone]

That rule does not apply.

 

[floyd]

I apologize for being so dense about this.

It's my understanding if filming at, say, 30 fps, the shutter speed should be set to 1/60th of a second. So if the slow motion setting on the Mini 4 Pro automatically records at 120 fps, would it not also automatically set the shutter speed to 250th of a second? And if it doesn't, would that diminish the video quality?

Basically, I'm wondering it the best slow motion video is offered through simply using the slow motion setting on the Mini 4 Pro, or manually set the M4P for slow motion then do it in post.

 

[Droning on and on...]

That rule does not apply.

Why not?

 

[akdrone]

Why not?

that rule is very specific to when a person desires motion blur when filming from a drone. Traditionally in film which was shot at 24fps a person waving their hand or a car driving by rapidly will show some blur. For many people recreating that effect is desirable. The complaint, again by many people, regarding modern video shot at 60fps or even 30fps with a shutter speed of 1/2000 is that there is no inherent motion blur. Recreating that effect of motion blur is best done shooting at 30fps with a shutter speed of 60. Once you are up into a fps of 120 and a shutter of 250 you aren't going to get any motion blur unless the action in front of you is really, really really fast. Additionally, most drone video is shot from...a drone ...mostly up in the air. If you are shooting a car driving by from 200 feet you still aren't going to get any motion blur even at 30/60. If you have a drone down low and are flying over an area or something is zooming past you then shooting at 30/60 can provide that cinematic feel and you ensure that fps/shutter speed combination by using the correct ND filter to get into that exposure range. With fixed aperture drones like the Mini 4 Pro that's your only real control. With variable aperture drones you have a lot more control regarding shutter speed. That's about all ND filters are used for when shooting video, except in some other unusual circumstances. I'll admit that I have never actually attempted to create motion blur by shooting at those kind of high frame rates and shutter speeds so somebody could tell me it works just fine but I'm at least reasonably confident in my assertion. As I often say, I was wrong about something a few years ago...it could happen again.

 

[akdrone]

I apologize for being so dense about this.

It's my understanding if filming at, say, 30 fps, the shutter speed should be set to 1/60th of a second. So if the slow motion setting on the Mini 4 Pro automatically records at 120 fps, would it not also automatically set the shutter speed to 250th of a second? And if it doesn't, would that diminish the video quality?

Basically, I'm wondering it the best slow motion video is offered through simply using the slow motion setting on the Mini 4 Pro, or manually set the M4P for slow motion then do it in post.

The M4P will NOT (as explained earlier) set it a shutter of 250 because it does not expect you are trying to achieve motion blur at those kind of shutter speeds, hence no reason to do that. To reiterate a bit from my earlier long post, the slow motion setting at 120 as explained earlier just does a trick by setting the meta data to 30 fps so your NLE plays it back in slow motion. You can also just shoot at 120 (for drones that can) and slow it down in post. Same effect. The only reason that shooting at 30fps "should" have a shutter of 1/60 is if you are flying low and trying to create some motion blur. If you're flying at 200 feet fuggetaboutit. Your too far away for motion blur to be a thing. The "slow motion setting" on the Mini 4 IS manually setting it to slow motion but it will still just pick any shutter speed it wants for the exposure unless you shoot Pro and choose one. If you put that footage into your NLE (Final Cut...Premiere...) it will show up as slow motion. If you simply shoot at 120 and put it into Final Cut on a 30fps timeline it will not appear as slomo but you can select any section of it and slow it down in post by 4x and it will be slow mo exactly like it would if you had used the M4P slomo setting. If you use the Pro exposure setting in a M4P and a set of ND filters to allow you to set the shutter speed to 250 there is little likelihood that it will look any different than had you not bothered and shot it at a shutter speed of 1000. Maybe it would be noticeable if you were down low enough and flying fast or if you had a race car driver go by you. Somebody with actual experience would have to chime in here but I'm thinking...nah...a shutter speed of 250 shot from most drone altitudes isn't going to do it (for sure) and even down low in almost any kind of "normal" filming you won't see motion blur in that circumstance.