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-   -   can I shoot in slow motion ?? (https://www.dvinfo.net/forum/open-dv-discussion/32337-can-i-shoot-slow-motion.html)

Mark Fan September 22nd, 2004 06:05 AM

can I shoot in slow motion ??
 
hey guys, I'm a new hand , so , just wondering , is there any DV cam can shoot in slow motion ?

Thanks

Rob Lohman September 22nd, 2004 06:38 AM

No. The DV specification only allows for 30 frames/60 fields (or
29.97 and 59.94 if you want to be exact) and 25 frames/50 fields
per second and nothing else. All the cameras that do 24p up-
convert this footage to 30/60.

Outside of the spec no camera has a variable rate tape mechanism
which you would need to record the higher datarates that slow
motion (= higher frames per second) requires or the variable
framerate CCD chips this would require.

Your only hope is to shoot in interlaced and then transfer this
to progressive slowdown in your editor. However, this might
not look that good and will definitely lower resolution and not
work with a lot of slow motion.

Otherwise you need to rend a high end camera or something.

Gale Smith September 22nd, 2004 08:17 AM

I shoot with a sony pd150 and you record at normal speed. When capturing to my editing software, the pd150 has a slo-mo play option that does not take away from the video quality. You do lose the audio, though. Then within the editing software, you can make further changes to the speed. And yes, messing with the speed within the editing software will take away from the quality a little. It depends on the software.

Chris McKee September 22nd, 2004 08:45 AM

<<<-- Originally posted by Gale Smith : I shoot with a sony pd150 and you record at normal speed. When capturing to my editing software, the pd150 has a slo-mo play option that does not take away from the video quality. -->>>

Are you capturing your footage through the anologue outs or digitally?

Chris Hurd September 22nd, 2004 09:05 AM

You can easily do effective slow motion in the editing stage, though. I use the Speed Controller utility from Canopus, and it produces smooth, steady "Peckinpah-style" slow motion (with very little to zero rendering time required).

Giroud Francois September 22nd, 2004 10:21 AM

there was a DV camera able to take picture at 100fps (samsung ?), but like other rare gadget it was hardly useful as it take only half vertical resolution.

Jesse Bekas September 23rd, 2004 10:05 PM

You can slow down any 30 fps video you shoot in any NLE, but without being able to shoot at a higher frame rate it will never look smooth like film slo-mo.

Mark Fan September 23rd, 2004 10:23 PM

Thank u all , so basically, if I want to shoot in slow motion, and look like a ferfetional , I'll have to rent a 8mm cam. is that right ?

by the way, Rob, can HD shoot in slow motion ?and maybe we can record it on a hard drive, like the latest JVC cam.

Jesse Bekas September 23rd, 2004 11:10 PM

Even with hard drive recording, you'd still need chips and processing that could go beyond 30fps, and no consumer/prosumer cams' can that I know of.

Norm Couture September 24th, 2004 07:47 AM

My NLE software is very basic, but I once managed to slow down a shot of a hummingbird while transcoding to MPEG2 for DVD with TMPGEnc.
I simply set the INPUT frame rate as 15 fps, leaving the output at 30 fps, and deinterlaced the clip. It worked.
The only problem: I couldn't figure out the way to extend the duration of the clip, so TMPGEnc made a half-speed clip with the same overall duration as the original footage. The resulting clip ends in the middle of the shot...
There must be way around this.

Jesse Bekas September 24th, 2004 08:14 AM

Yeah, but all your doing is shooting at 30 fps and showing at half speed, which is jerky (looking, not you). Essentially what's happenning when you just plain slow down a clip in your NLE is showing the same frame twice (or more) and adding some blur in between frames to make it appear "smoother". What you need to be able to do is shoot at a higher frame rate than 30fps and then playback at 30fps. (i.e. shoot at 90fps and showing at 30fps will give you 1/3 normal time motion in the same clarity that regular shot and viewed 30fps video is in). Again, shooting in a higher frame rate is the key here, nobody's NLEs are magically going to be able to make clear in-between-frames from nothing.

H-wood even gets slo-mo wrong sometimes. Have you ever seen a show or movie where the slo-mo looked jerkier than the rest of the content. That was either a creative decision (jerkiness for jerkiness' sake) or the director/editor said in post, "I wanna slow that shot down". They are bound by the same shooting to viewing frame rate ratios as we are. If they don't prepare in production for slo-mo shots (shooting at a high rate), they get the same jerky crap we do, albeit with a little more polish.

Rob Lohman September 24th, 2004 08:23 AM

Mark: no, HDV (substandard of HD) is bound by a standard as
well and a bandwidth to work in.

Rob Simon September 27th, 2004 01:01 PM

Slo-mo is such a common thing for people to do, why doesn't anyone make a DV camera that can be "overcranked"? Is it just too difficult mechanically, since I guess the tape would have to move faster? Or is that the manufactures figure the software solution is good enough. Just wondering.

I love the great Hollywood slo-mos that were obviously done at a high frame rate.

Rob Lohman September 27th, 2004 02:02 PM

I'll re-iterate my answers from above:

1. the DV spec does not allow for any other framerate, nor does the HDV spec

2. it is very difficult to get a tape system to do that reliably

3. it takes a lot more power in the camera's than the current models to process and compress the higher bandwidths required

The only way I see this happening is if camera's record straight
to harddisks in some other format than DV (probably MJPEG or
something).

Mark Fan September 28th, 2004 02:34 AM

I do agree with u on the hard disk option, it would be great if some manufacture can do so, so far as I know only JVC has one model that has a hard drive recording system, but it's only for consumer use, I guess the next step would be for prosumers.


<<<-- Originally posted by Rob Lohman : I'll re-iterate my answers from above:

1. the DV spec does not allow for any other framerate, nor does the HDV spec

2. it is very difficult to get a tape system to do that reliably

3. it takes a lot more power in the camera's than the current models to process and compress the higher bandwidths required

The only way I see this happening is if camera's record straight
to harddisks in some other format than DV (probably MJPEG or
something). -->>>


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