The tradition shutter speed is generally measured as an angle and the norm is 180deg. So at 24fps the shutter speed is 1/48.If you're taking 1fps then it should be 1/2.

Bob, can you elaborate a bit on this? I'm not familiar with shutter speed measured as an angle, and don't follow how you get from 180deg and 24fps to 1/48. I do know that the default shutter speed on my video cam at 24fps is 1/48 so it must be related to what you are saying. Educate me?

Jerry

In a film camera the shutter is a spinning disk with a cutaway segement. The size of the cutaway is measured as an angle e.g. at 180deg the shutter is open for half of one revolution. As the shutter rotates one revolution per frame then at 24fps the time the shutter is open is 1/48.
If the camera is run faster say 30fps the angle remains the same and the shutter speed is now 1/60. Traditionally in a film camera shutter speed / angle is not used for exposure control. It is used in a video camera and this in part can explain the difference between the look of film and video. Most video cameras can be setup to not use shutter speed for exposure control. Some let you define shutter speed as an angle.

Bob.

> Is there a clever alternative to AAE that allows me to run an AAE plug-in from Vegas

Yes, Boris FX and Boris RED will do this but they don't run all AE plug-ins so you would have to check for compatibility. I've had great success with the DigiEffects plug-ins which are really nice.

For FREE (and I've used this and it works well) get VirtualDub and use Donald Graft's DeFlicker plug-in (also free). I've used it on film that was captured via camcorder and it took the 24 frame flicker right out if. Your experience may be different because you probably don't have a constant flicker (i.e., each frame has a unique and different exposure).

Of course, the real solution is to shoot in manual mode next time so that your exposure stays constant. If your camera doesn't have manual controls, see if it has a "photo stitch" function. This uses the exposure of the first picture for all remaining pictures until turned off.

~jr

Jbrawn is using a still camera though.

I *think* I know what he's talking about. When I shoot a series of stills with our Nikon D90 at work they often have exposure variations even when I'm pretty sure everything is locked down. Maybe it's a bit like clamping or something, but the exposure hasn't been crucial enough for me to try to hunt down and squash the phenomenon.

Rob Mack

Still camera, video camera, they both do the same thing. Shutter speed, aperature, resolution, gain, white balance.

In jbrawn's case there's another source of flicker that's worth a mention, clouds on a windy day. The setting or rising sun I think also goes through a series of steps in light levels.

Bob.

Thanks everyone for your comments and suggestions! The flicker I'm seeing is minor, random, and I believe is related to imprecision from shot to shot in either the iris or shutter speed of the point and shoot camera I'm using. I think Rob Mack is on the right track about the cause.

I'll give VirtualDub and Donald Graft's DeFlicker plug-in a try. The price certainly seems right!

I was trolling a couple of time lapse forums and I learned today that my model camera is more stable when forced to the smallest aperture (f8 on my model). I'll also be giving that a try.

Bob Farss: you've given me something to contemplate. I understand what you are saying about 180 degrees on a film camera. (In my line of work we'd call that a 50% duty cycle.) I wonder if that translates in time lapse... If I want to shoot a frame every 5 seconds (120:1 time change at 24p) should I be leaving the shutter open for 2.5 seconds on each frame?

I guess a few more all-nighters and I'll know a lot more than I do today.

Thanks everyone for your help!

John.

I thought Bob was crazy when he talked about using a slower shutter speed when doing timelapse, but then I thought about the timelapse he posted in a parallel thread (to this one) a few days ago, where he showed cars zooming by at about 60x normal speed. I thought about that, and if he had used the normal 1/50 second (PAL) shutter speed, the video would have shown a series of parked cars jittering all over the screen. This wouldn't have looked right because cars moving at 360 mph would look like a blur to the naked eye. So, the idea of using a slower shutter speed is a good one.

Bob will forget more in the next ten seconds about film than I will learn in a lifetime, and I think he also mentioned a few years back that you can use the Motion Blur feature in Vegas to simulate some of this slower shutter speed, if you didn't use the slow shutter in the first place.

And, as far as the angle of the opening in the shutter wheel, I don't think it imparts any special feeling to the film that a focal plane shutter or leaf shutter or any other mechanism for interrupting the light, but I definitely could be wrong on that and would be interested in what Bob has to say.

"And, as far as the angle of the opening in the shutter wheel, I don't think it imparts any special feeling to the film that a focal plane shutter or leaf shutter or any other mechanism for interrupting the light, but I definitely could be wrong on that and would be interested in what Bob has to say. "

As far as I know the rotating disk is the only type of shutter used in a movie camera. I recall from somewhere some discussion about the shape of the cutout having some minor effect on the image. I haven't rolled film in 30 years, I just keep an interest and memory of that alive because of the interest in that elusive film look. I find understanding how those cameras work makes the challenges easier to understand. The great thing about a film camera is you can see how it works.

The point I was trying to get at is that video cameras can use shutter speed as a way of controlling exposure and faster shutter speeds can impart that Saving Private Ryan look where motion becomes juddery.

I'd also imagine in a movie camera the way the shutter works must have some effect when doing speed ramps

In a still film camera the different types of shutters do have some impact. The old roller blind shutters can make car wheels become oval. The leaf shutters were much desired I recall, I think because they could sync to flash at higher speeds.

I just found an interesting article here:

http://wapedia.mobi/en/Time-lapse?t=3.

this talks about shutter angle and time lapse etc. As I found out shooting 1 fps with an effective 180deg shutter means you need what heck of a lot of ND filtering!

Bob.

JR, Can you explain how that deflicker thing works on film. I sometimes get film flicker that I'd like to improve or get rid of. Is this re-working individual frames or something else. What does it do to rendering times?

Lynn

You really need a camera that forces a fixed sutter/iris, full manual control. I gave up trying to do even a 1 hour, every 10 seconds sequence on a point and shoot.

If you are outside, even that causes some issues, as clouds passing by can cause a harsh change.

You might try the software tools, I'll follow the results to see how it turns out.

Time lapse requires total control to pull off. Nature normally doesn't cooperate with that.

At the moment I am recording the build of my daughters new house with a 'shot n point' with the shutter operated by a slow motor mechanism from 555 timer circuit (every 15 secs). The results are ok but sometimes think that the 'shutter' button is not being pushed slowly eneough to allow auto exposure to settle. Manual might help but think passing clouds would be even worse variations. Will experiment.
LoL the other night about 11pm I suddenly remembered I hadnt retrieved the camera, had 3,600 shots on a 2gig card with 1,200 of 'em jet black.
Brian

Here's my third attempt. This was shot on a canon SX110 using PC based software control with one exposure every 4 seconds. I locked the ISO and iris with the software and allowed the camera to change the exposure time based on it's internal light metering.

Each of these frames averages around 1/60 second, so it is nowhere near a 180 degree shutter wheel. This is definitely the "series of parked cars" approach. I'll need to get a really serious neutral density filter to be able to have a 2 second exposure every 4 seconds.

I know this isn't high quality video, buy my daughter and several of her teammates enjoyed it over and over.

http://jbrawn.com/TL/pinkpride091017.wmv

John.

Hi John, fun thing to do for your daughter and her friends!

I am also interested in learning more about time lapse. I've done a few with my DSLR without realizing all the nuiances to consider.

I will be interested in hearing what others have to say, but I think a 2 second exposure would be excessive - too much motion blur?

Also, it seems to me it would be better to set the exposure for the brightest expected, and lock it down. I think it would look more natural than the pulsing from the cams auto exposure.

But as I said, I have plenty to learn about time lapse and look forward to other comments. Thanks for sharing your efforts here.

Jerry

Certainly locking down exposure is a step in the right direction.
If you are taking one frame every 4 seconds then a 2 second exposure is correct. Yes you will get a lot of motion blur, what do you see if someone run past you at 1,000 mph?

Of course even with the technically correct amount of motion blur happening you can hit another problemo. When something stops moving. The blurry people or cars go from 1,000mph to 0 mph in no time. You get to the point where our brains know nothing can undergo that acceleration without going splat, we've created a visually impossible scenario.

Time lapse works best at showing us things we cannot normally see. The construction of a building in a few minutes or the opening of a flower. We're shifting time from moving so slowly we don't see anything happening to a time frame that's still in our world. In these cases all that motion blur can really work for us. It will blur out the workers on a building site for example, they can be made to simply vanish. Without the motion blur we simply see these ant like workers jumping around from frame to frame which really distracts from the main show of the building rising from the ground.

For the shots of the football field getting the camera up a bit higher, maybe on a pole, would stop the problem of people walking close in front of the camera. It might also give a better view of what's going on. Just hope there's no wind, a shaky camera taking time lapse might not be a good thing.

Bob.

Without the motion blur we simply see these ant like workers jumping around from frame to frame which really distracts from the main show of the building rising from the ground.Which is exactly why using a slow shutter speed is the WRONG thing to do in many circumstances.

What I am saying is that Bob's advice is correct if your desire is to show what a car looks like when travelling at 6000 mph, which is what happens if you tape pictures of cars on a highway at 100x real time using time lapse.

But what if you are taking pictures of your kid's soccer game? Well, if you use the same technique (of using a slow shutter speed) you end up with ---

NO ONE ON THE FIELD!

I actually tried this last night after I looked at the soccer (football) time lapse video and thought it would be interesting to see if I could simulate motion blur after the fact, since the time lapse had been done with a fast shutter, contrary to Bob's advice. So, I tried motion blur in Vegas. However, as I quickly found out, much like supersampling, it only works on things generated within Vegas itself.

Useless.

So, I created a motion blur using AVISynth and motion estimation. This worked great, but as I increased the motion blur, thus simulating a really slow shutter speed, the players became ghosts and eventually disappeared altogether.

Which pretty much negates the whole purpose of the exercise: what good is a time lapse of a soccer game if your technique makes all the players disappear??

So, getting back to my point, you really have to ask yourself what you are trying to do. The idea of simulating what an object would look like when sped up is certainly valid, and if that is what you want to do, then you definitely should follow Bob's (farss') advice to the letter. However, based on many time lapse examples given in this thread and that I have seen over the years (like the building construction), I am not convinced that having all the objects blurred is going to give you the result you want.

Remember, time lapse is NOT showing reality to begin with, so the idea of using a technique to better simulate reality may not always be valid.

Since this is an "artistic" argument, there is no right answer, and I am not actually not disagreeing with Bob (his technique and argument are 100% correct), and am not trying to start an argument.

You are entirely correct.
Apply enough motion blur and you will make anything moving vanish.
This can be a useful technique, you want a shot of a public building without the people, that's how you do it. In fact this was a trick question I came across decades ago. How do you take a photo of a building without showing the people. The answer is to expose the frame 100 times with 1/100th the exposure. Recepocity (spelling?) failure of the film takes care of the rest. I don't know if this would work with a DSC though. You can as you've seen do it with a video camera.

There is a third technique which does looks rather stunning. Expose each frame with two different shutter speeds. Not the easiest thing to do but it can be done if you've got a huge budget. You need a massive flash gun or a number of them. Synced to the camera's shutter you get a frozen in time image from the extremely short flash plus you get the motion blur from the normal shutter, The only lighting source capable of the sustained power needed to do this are the Lightning Strike lights and a bank of them firing off would be something to behold.

Putting my thinking cap on it should be possible to simulate this in post. Shoot at normal speed with a normal shutter speed. Speed up in post say 10x and apply motion blur, just enough so you get visible trails. Got back to original footage and drop all but every 10th frame. Composite the two.
The comet trails from the motion blur show the eye how the objects moved. The frozen frames let the eye clearly see what it was that moved. You get the best of both.

Bob.

Those are some very cool ideas, Bob.

As for the open shutter and then flashing, that's how my dad used to take flash pictures: hold the shutter open, and light the flash powder. I have done similar things where I opened the shutter and then walked around popping the strobe, illuminating different parts of a large room (hiding behind a desk or plant). Saves having to set up a dozen lights.

"So, I tried motion blur in Vegas. However, as I quickly found out, much like supersampling, it only works on things generated within Vegas itself. "

No. Motion Blur does work on anything.
However and where you might be getting a bad outcome is it is applied to the video output buss. So if you do any speed changes to a clip the MB gets applied AFTER that which is probably not what you want.
To get the desired outcome you need to add the clip to a project, apply no speed change but add the MB. Then nest that in another project and do the speed change there.

Over the years I've used Vegas's MB many times and made good money repairing damaged tapes using not much more than it. What Vegas's MB does not do is create MB through interpolation or optical flow processing. The cheapest commercial product that'll do that is AE with some fancy plugs.

Bob.