Motion blur and rolling shutter in 5 mins

This short video will show you all you need to know about motion blur and rolling shutter.

[@KevBinge]

This is such an important video. Well done and explained. “It’s never perfect.” -Best quote of the millennium.

[@BlenderBob]

(C) 2022 Blender Bob inc

[@retroeshop1681]

I swear this info is gold, I follow 20+ blender and CG channels and none of them discuss stuff like this or other topics you do ♥

[@BlenderBob]

Thank you so much

[@GaryParris]

and thats because none of them really have had photographic or video experience beyond the home. ;O)

[@retroeshop1681]

@@GaryParris Some of them you could say so, but most of them also work in the industry, but I think they go with the mainstream route and they just cover mainstream topics, with Blender Bob that's not the case it has something of everything, I always recommend his channel as my #1 Blender and CG channel to have in your feed.

[@GaryParris]

@@retroeshop1681 some of them yes, and of course many are going to do mainstream things, but even within the industry they aren't necessarily doing the whole thing themselves that's what pipelines are for, that's what assets are for, which takes care of much of the behind the scenes many popular blender channels are not people working in actual industry but have grown with blender learning it before their audience even gurus. Anyway point is blender Bob is showing how to do the industry fx stuff and learning blender as well so it's a great channel we can recommend to others and appreciate ourselves.

[@retroeshop1681]

@@GaryParris Sure thing, that's why I follow them and I'm subscribed to them, they all have something to add to the community, I'm aware of all the things you said, and obviously covering the mainstream stuff also brings more views to their channels, so no shame on that, and as I said, yes, many of them are not in the industry, for example Blender Guru, the most popular Blender channel, he is not in the industry and yet he is the main channel, I'm also subscribed to him, I had my first baby Blender steps with him haha but many others such as Pierrick Picaut, another excellent Blender channel with tons of useful information and courses, completely underrated, and there are other such as FlippedNormals, they are also really popular cause they cover mainstream stuff, as good, but we need more like Blender Bob and Pierrick Picaut, with more variety of information, directly from the hands of those who work in the industry, all good, but I recommend more the channels like those haha

[@aliensoup2420]

One other important consideration when integrating motion blurred shots with CG is coordinating the shutter timing with the blur position, which you briefly mentioned. The difference is between tracking the blur "leading edge", "trailing edge", or "blur center". In my experience, I always tracked blur center and never had a problem for years. Then, at some point, the lighting and render folks started getting creative with the shutter timing, and choosing their own settings without telling anyone. Suddenly, match-moves that were approved by the Sups, were getting kicked-back after rendering and compositing. The proposition was to re-track the shot, which in some cases could take days, or even weeks, depending on the shot. Fortunately, at that point in time, I had a custom Maya tool that could selectively retime motion curves in the Graph Editor. Just 5 or 10 minutes isolating the blur frames and repositioning the motion curves to match the timing of the render shutter, fixed the problem without needing to re-track the entire shot. Just something else to be aware of. Always maintain close communication with the cg sups, pre-comp, and lighting/composite people, to insure proper coordination of background plates and tracking requirements. And ALWAYS track the original (undistorted) plate (with the possible exception of Rolling Shutter correction).

[@BlenderBob]

Awesome comment!

[@brokensigil]

I was happy and sad at the same time when I saw the notification pop up for this video. Happy because I get a new dose of Blender Bob and sad because It's only 5 minutes. Thank you soo much for the videos you make you are a legend and a hidden gem in this community

[@MichaelHickman3D]

Wonderful video, your ability to explain everything in detail is super effective for teaching. Thank you so much.

[@AdamEarleArtist]

There really isn't that much to think about when it comes to comping in terms of just everyday run of the mill toolswe need as compositors. You might be the man to put that list together and let the community of developers know.

[@BlenderBob]

They can always read the Nuke manuals… ;-)

[@homspau]

Great video! Super well explained!!

[@pmquiram]

I was just looking for a good explanation of this. And for a bonus you explained the global shutter on the camera the videographer I work with has

[@jkartz92]

would be great if you could demonstrate the use of vector pass in nuke & fusion like you did for z depth!!

[@BlenderBob]

first you need this: kzbin.info/www/bejne/bnivZIuImZujec0

[@poopiecon1489]

Much needed video

[@andreasnoutschmidt9964]

Thanks Bob, as always very informative. I'd love to know if you ususally opt for Nuke for adding the motion blur using the motion vectors, and if so, how you go about it. (Eyeballing?)

[@BlenderBob]

I try to avoid motion vectors as they will create artefacts. Real motion blur will barely make an impact on render time so might as well use the real thing.

[@rohanphulari356]

nice house i love it i wish i could also get like that one in future

[@darshjoshi1641]

You should work on your SEO! Your videos are awesome and the content is so unique... Start putting 1min videos, they trend easily. I really appreciate all the industry knowledge you share. Thanks

[@patriciocalvelo1839]

Thank you for all this useful information! Have a great time off!

[@fabbrobbaf]

Thanks Bob, enjoy your holidays!

[@saiki3742]

Educational and entertaining at the same time, How do you do it? Amazing!!! 😄

[@BlenderBob]

Well, it’s starts with a camera on a tripod…

[@vaporama_vision]

I could watch that kind of videos for hours 😌

[@alexandreancel6423]

Super useful, thanks ! Have a great summer !

[@deadpin]

Neat trick: That Shutter value is not strictly 0..1, it's the number of frames over which the blur can occur. So if your framerate is 24fps you can type 3 there to get a blur as-if you were shooting at just 1/8th a second.

[@BlenderBob]

Oh really? It’s not in the documentation.

[@deadpin]

@@BlenderBob The docs say "Time (in frames) between when the shutter starts to open and fully closed. For example, shutter time 1.0 blurs over the length of 1 frame." But, now I'm not sure of my 1/8th sec calculation. Changing scene fps to 60 yields the same image... would have to ask around.

[@M4Pxls]

I've to say that, blender Bob is great at doing the jello effect!

[@unboring7057]

Great video as always, have a great summer Blender B, will miss your vids!

[@gabrielmoro3d]

Thank you!

[@chrisbonnie5464]

Thank you

[@mike2636]

OMG thank you for this video! Would it be possible for you to do a video doing the warp trail like in Star Trek. Thank you again for this tutorial!

[@GaryParris]

Yes well done, it's good to give people this info, :) enjoy your Summer BlenderBob, good luck with your new project :O)

[@samdoyle9048]

great video, many thanks!!

[@blendercomp]

enjoy your holiday! :)

[@tor3203]

Good luck with the new project, Blender Bob

[@moomin2162]

5:43 what do you use for tracking? :) I always had problems with motion blur in the blender tracker.

[@BlenderBob]

I don’t track myself often. When I do I use Nuke for simple stuff but at the office we use 3D equalizer

[@moomin2162]

@@BlenderBob thanks! great tutorial as always too!

[@GaryParris]

@@BlenderBob give it a go in blender ;O) vids to checkout for that would be Ian "lazy tutes" and cg matter among useful ones but others in community have good tutes

[@veruzzzz]

So basically Rolling shutter ON will give you more "realistic" camera behaviour? I've never even thought about this feature being present in Blender at all despite using motion blur almost every time (with default curve - also new info for me). Thanks for the video!

[@BlenderBob]

It will not make it more realistic. It will just match the distortion of the plate. Ideally you shouldn’t have any rolling shutter in your footage.

[@Kram1032]

(unless, to add to that, you specifically want it. There are some really cool videos out there specifically exaggerating the rolling shutter a heck of a lot and it looks amazing)

[@veruzzzz]

@@Kram1032 Yes, this is what I meant. E.g. you should not have any chromatic aberration in the footage but adding that in post-pro makes things more authentic sometimes etc.

[@hasanhuseyindincer5334]

👏👍

[@roger4845]

My character moves really fast all the time and it looks jarring even at 60 fps. With motion blur it's smooth, but quality drops. Should I just leave it with motion blur?

[@BlenderBob]

Depends on the look you are looking for. If you want it to look like a feature film, you should render at 24 fps. You will lose details with the motion blur but it's more pleasing to the eye and looks more realistic.

[@roger4845]

@@BlenderBob okay, thank you.

[@yima8282]

Im only starting to use multilayer, and i am a bit confused with converting vector pass to motion blur.

[@BlenderBob]

First of all, you should render with real motion blur instead of motion vectors. You will get a much better result. If you still want to use the vectors, this is not something I can explain in the comments but I'm sure you could find a clip on YB that will explain it. :-)

[@yima8282]

@@BlenderBob Thanks for replying, love your videos. I'm only doing this 'cause i heard it is better to render this way instead of burning the motion blur into the frame. So is it not true that it is better to do motion blur on compositing?

[@BlenderBob]

@@yima8282 no, motion vector blur is a 2D cheat and it will create artefacts when two objects move in different directions and cross each other. I explain this in one of my clips but I don’t remember which one

[@Kram1032]

4:00 shouldn't the rolling shutter be on the same scale as the full shutter? Like, 0 means no time, 1 means one full frame (or it might mean two frames worth of time, like, from the current frame's previous frame to the current frame's next, so you might need a factor of 2 in there) but from that, and knowing how many frames there are in a second, you ought to be able to calculate the appropriate setting for any given camera EDIT: oh wait I guess the scales are inverted. I figured 0 would mean least rolling, not maximum rolling. Still, the rest should apply

[@BlenderBob]

Rolling shutter should have the same scale as the camera. It should be in milliseconds, not from 0 to 1.

[@Kram1032]

@@BlenderBob I guess it really should show/allow to set both. Fractions of frame are arguably more intuitive than ms, since ms is gonna depend on the frame rate. If you change the framerate, how many ms it is will suddenly change meaning. Of course that's a non-issue for movies with their fixed default frame rate, but it's an important consideration imo. It should be pretty easy to code up like a conversion utlity thing though. Ideally that should be built in of course, but still, it should be fairly straight forward math at least...

[@BlenderBob]

@@Kram1032 frame rate has no influence on the shutter angle.

[@Kram1032]

@@BlenderBob this was about the rolling shutter though. You said that one is measured in ms so it can be calculated as a fraction of a frame. Shutter angle is a different matter, yeah. Not sure how to deal with that part

[@0zyris]

@@Kram1032 The shutter opens, spends a period of time open, then shuts. It is not take the entire duration of the frame to open and close. As an exaggeration, on a one second exposure, the shutter does not take half a second to open. As Bob says, the shutter speed bears no relation to the shutter angle. As long as the cumulative time of the opening and closing of the shutter is less than the total frame duration, say 1/48, it doesn't matter.

[@magnuzoid]

Wouldn’t you be able to do ‘negative rolling shutter’ on footage in blender? Not by an install atm so just wondering

[@BlenderBob]

Negative? To do what?

[@magnuzoid]

@@BlenderBob like uhm.. compensate for the shutter by setting a negative value.. sorry for the lack of description haha, but to avoid after effect 🙂

[@Kram1032]

@@magnuzoid the rolling shutter is a render setting, not a compositing setting. Unless you're saying "put the footage on a plane and reproduce the camera motion, except in the exact way that would cause the opposite shutter effect" (which might *kinda* work but sounds like a wild setup for something that probably isn't gonna yield that great results) I don't think what you are describing is possible in Blender right now

[@magnuzoid]

@@Kram1032 thanks for clarifying - I’d love to do all inside Blender 😅

[@alisk10]

what do you use for tracking?

[@BlenderBob]

I don’t track myself often. When I do I use Nuke for simple stuff but at the office we use 3D equalizer

[@bcholmes635]

Will you be at the Blender conference this year?

[@BlenderBob]

I certainly hope so

[@BlenderBob]

Shutter angle and shutter speed are not the same thing. Movies are always shot at 1/48 th of a second. The shutter angle is independent of the shutter speed. Breaveheart was shot a 1/48 with a shutter angle of 180 (or 0.5 in Blender) but Saving Private Ryan was also at 1/48 but with a shutter angle of probably 90 degrees, or 0.25. You don't have the shutter angle on DSLRs. You need a professional camera for that.

[@flannel.and.film.9045]

I didn't even know there was a shutter curve until I saw you click on it...🤦‍♂️

[@AmitKumarsangam-bs6fi]

😅

[@AmitKumarsangam-bs6fi]

Why me render is black when I turn on motion blur 😢

[@BlenderBob]

?!!

[@konotori_vfx]

0:48 is there any way to convert this Blender Shutter value not to degrees of shutter angle but just to fraction of shutter speed like in digital cameras?

[@BlenderBob]

How does it work on your camera? Never heard of fraction like you talk about.

[@onjofilms]

@@BlenderBob It's a fraction of a second. Like 1/4000th

[@user-kv5py1qn8d]

@@onjofilms multiply value you mentioned by FPS

[@konotori_vfx]

@@BlenderBob this is fractions of seconds: 1/100, 1/200, 1/400 and etc. It means that sensor will receive light during 1/100 of a second, 1/200 of a second and 1/400 and etc of a second respectively. You've definitely heard about it, it's just that I'm probably not explaining well. Watch this video, that's what I'm talking about: kzbin.info/www/bejne/bYOci4eupLmCic0 (the link have built-in time-code, you will be automatically moved to a needed moment of this video)

[@BlenderBob]

@@onjofilms If you are talking about shutter speed, it's not the same thing. Movies are always shot at 1/48 th of a second. The shutter angle is independent of the shutter speed. Breaveheart was shot a 1/48 with a shutter angle of 180 (or 0.5 in Blender) but Saving Private Ryan was also at 1/48 but with a shutter angle of probably 90 degrees, or 0.25.

[@AmitKumarsangam-bs6fi]

Hlo

[@markymrak]

Hey BlenderBob thanks for the informative video, love your channel. Are you encountering issues with motion blur and mesh deforming in Blender and how do you solve it? I'm referring to these mesh flickering issues described in these two videos: kzbin.info/www/bejne/e5DCe6WnrpJ9gpYsi=MGwH_6Rg8pbmcxYm kzbin.info/www/bejne/e5DCe6WnrpJ9gpY Although they offer some some workarounds these are not a solution that will work every time and give desired results.

[@BlenderBob]

Turn off auto smooth