Slow motion shots

[marc]

I just shot a cart at 32 frames per second today. I will get it processed and if Roger is still offering the free sample transfer and it turns out o.k. after it is processed, i'll give that a go. It is nothing special. Just some casual footage shot at Universal Studios Orlando.

[VideoFred]

Alternatively, if I shoot my film at 36fps and transfer it at 12fps, I imagine I will have more latitude for making speed adjustments in the NLE software, because there is literally more information on the tape.Steve

OK, I admit: I have never seen a flying spot machine, but I can imagine how it works. It scans line by line. I think you are mixing frame rate with scanning speed. These are two different things.

So, in my humble opinion:
I do not know if one can change the scanning speed of a flying spot machine. If so, then indeed quality would improve with slower scanning speed. I also think these machines are running very very slow.

But this has nothing to do with frame rates and/or play speed of your film. This is done after the scanning process. Probably at the same time, with hardware frame rate conversion equipment.

Please someone correct me if I'm wrong.

Fred.

[Justin Lovell]

i've been told by one transfer house that if they're doing 4k scans it can take up to 6 seconds per frame to scan it in.

8O

[MovieStuff]

I just shot a cart at 32 frames per second today. I will get it processed and if Roger is still offering the free sample transfer and it turns out o.k. after it is processed, i'll give that a go.

Actually, I have very little to do with the telecine part of our business as my wife runs that. Her policy is that she'll do a free test transfer if you need to see the quality of the service but, otherwise, she charges for any other footage. It all depends on how busy she is and right now she's pretty swamped so you'd need to email her to see what the schedule is like these days. If you've never sent in footage before, I'm sure she would not mind doing the free test for you.

Roger

[marc]

I figured that the test was a maximum of one fifty foot roll if that. I have never used the service before but I'd be very interested in seeing the results.

[steve hyde]

Alternatively, if I shoot my film at 36fps and transfer it at 12fps, I imagine I will have more latitude for making speed adjustments in the NLE software, because there is literally more information on the tape.Steve

OK, I admit: I have never seen a flying spot machine, but I can imagine how it works. It scans line by line. I think you are mixing frame rate with scanning speed. These are two different things.

So, in my humble opinion:
I do not know if one can change the scanning speed of a flying spot machine. If so, then indeed quality would improve with slower scanning speed. I also think these machines are running very very slow.

But this has nothing to do with frame rates and/or play speed of your film. This is done after the scanning process. Probably at the same time, with hardware frame rate conversion equipment.

Please someone correct me if I'm wrong.

Fred.

First I should say my theory about transferring at slower frame rates is all unconfirmed guess work. I will ask the next time I talk to the posthose.

But I should also say that I'm not talking about scanning speed. I'm talking about running time on the tape.

Evan and others sound like they are quite certain that stretching 20 mins of footage onto 40 mins of tapestock is nothing more than a waste of tape and time.

My guess is that in some situations - like when a take is made at 24fps and later the director decides they want the take in slow motion - it would be advantageous to lay that footage onto the tape at 12fps instead of slowing it down in the NLE software. I think it might look better.

My guess is Roger Evans can confirm or disprove this - but didn't when he made reference to 60fps played back at 60fps looking like video.

I'm NOT saying this is a practice to strive for. Clearly slow motion footage should be shot at the highest frame rate one can afford. If I make a take at 120fps I can speed it up to look like 60fps if I want to, but not the other way around.

[mathis]

My guess is that in some situations - like when a take is made at 24fps and later the director decides they want the take in slow motion - it would be advantageous to lay that footage onto the tape at 12fps instead of slowing it down in the NLE software. I think it might look better.

If the NLE speed change is of decent quality there would be no difference at all. If you give it a speed change of 50% it just doubles the frames, nothing else what the transfer house would do.

[MovieStuff]

My guess is that in some situations - like when a take is made at 24fps and later the director decides they want the take in slow motion - it would be advantageous to lay that footage onto the tape at 12fps instead of slowing it down in the NLE software. I think it might look better.

It will look exactly the same. Let's take something with easier math, like footage shot at 30fps instead of 24fps. If you tranfer at 30fps ( I know, really 29.97 blah, blah, blah) then each frame of film ends up on a single frame of video. Therefore, playback will look normal. If you transfer that same footage at 15fps during telecine, then it will simply put each frame of film on two frames of video. Using slow a speed change in your NLE will do exactly the same thing by doubling each frame. If you transfer 24fps footage at 12fps, the resulting footage will have a multitude of interlaced pulldown frames that will be near impossible to get rid of if you wanted to change the 12fps footage to another speed. Therefore, if you have 24fps footage that you think you might want to use for slow motion, you would be better to have it also transfered at 30fps so that you maintain frame discretion for future speed changes on your NLE. Otherwise, you would need to use software to remove the pulldown frames to re-establish frame discretion.

Now, having read through this somewhat confusing thread, it appears that you might be suggesting shooting at a higher frame rate on all footage to allow for more speed options later. If so, then you would want to use even multiples of either the normal film rate or the normal video rate for smoothest motion. I would suggest frame rates of 30, 48 or 60fps. That would give you more frames to work with when you do your speed changes. Not really practical, in my opinion, but it is done all the time in action films where they shoot fight scenes at high speed and then pick out patterns to restore normal playback rate so they can instantly jump to slow motion without having to ramp up or cut.

Roger

[Justin Lovell]

if you shoot an action scene all at high speed is it common practice to

A) keep the added frames to have smoother motion when playing the film back at a normal speed

or

B) pull out the added frames for normal speed, and replace them for the high speed scenes?


The reason I ask this is that I forsee an asthetic difference in doing the high speed 'ramping' in camera, as the normal footage before the ramp will have a more 'filmic' feel being shot at 24fps.

If the whole scene was shot in camera at high speed and 'ramped down' to 24fps in the NLE then ramped back up to high speed, it should have a much different asthetic motion feel as the '24fps/normal' speed footage will have more frames to smooth out the motion?

how is that dealt with normally?

[steve hyde]

....thanks for these explanations. I have a lot to learn about video tape.

Steve

[MovieStuff]

if you shoot an action scene all at high speed is it common practice to

A) keep the added frames to have smoother motion when playing the film back at a normal speed

or

B) pull out the added frames for normal speed, and replace them for the high speed scenes?

If you shoot something at, say, 48fps and then use every other frame to create 24fps, it will simply look like 24fps shot with a more narrow shutter opening. Less blur and more hard edges, which create a slight strobe. You can see it in a lot of action films that shoot high speed and then use selected frames to restore standard speed.

Roger

[mathis]

....thanks for these explanations. I have a lot to learn about video tape.

Steve

Slowly I get the feeling you are/were thinking of the video tape as an analog format like the analog audio tape. Then I somehow get your thinking style. But video tape is frame discreet, it is 'digital' in the time domain, even analog video tape. Not comparable at all to analog audio tape, which is "analog" (grid-free) also in the time domain.

[steve hyde]

...yes, I was thinking analog. That is just how my brain works.

Steve