DV shooting 25 fps

[The Woddler]

As you probably know, normally DV is shot at 50 fields per second. I'm currently working on a low-budget drama series- one of the directors has decided to shoot at 25 fps on the PD150. I can't beleive how good the rushes look- far more filmic, and while it has some downsides (e.g. blur/trail on movement) it certainly gives the image 'something' that normal, flat DV lacks.

In short, I'm a total convert!- has anyone else had experience of shooting at 25fps?- I'm assuming that it might not work so well in an action piece with a lot of movement.


W

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[tim.callaghan]

I could've swore the the NTSC version of the PD150 only does 15fps progressive scan, which would equate to the PAL version probably only doing 12.5 fps. I do say probably though, it's just I've never heard a report of a PD150 doing 25fps, which is probably one of the main gripes about this camera in comparison to it's Canon counterparts.

Tim

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[Rar]

People are often confusing fps with shutter speed. PAL's field/frame (I'm not sure which) rate is 25fps and cannot be changed. The shutter speed is the amount of time the shutter remains open for one frame it can either be 1/50th of a second or 1/25th of a second or 1/15th of a second etc etc.

I could be horribly wrong. Please feel free to correct me.

I do agree using a lower shutter speed can make the footage look less videoie (more filmic), and you don't need to use as much light. But on the down side you lose some shapness because the camera loses fields. And you can end up with a little more noise (depending on the camera). I personally prefer to use smart deinterlace in post. That way you retain the sharpness and still get the effect, you can even add a little motion blur.

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[This message has been edited by Rar (edited March 01, 2002).]

[This message has been edited by Rar (edited March 01, 2002).]

[The Woddler]

Hi guys,

Maybe it is 25 frames/sec that I'm on about- this is what I thought it was, but the director insisted that it was fields/sec. I take what you mean about preferring to do it in post, but if you can't afford it....

Regardless, I can't believe what an impressive (yet usable) effect it gives.

W

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[steven_craig]

whoa! this is all going out of control

DV PAL is shot at 25 Frames Per Second (FPS) - and rar it can altered as we are discussing here, to 12 or 15 or 90 FPS depending on the camera you have. DV NTSC is shot at 30 FPS.

rar - shutter speed is more film based, not a term usually used in DV cinematography, because there is no mechanisim like that inside the camera. DV's shutter speed is altered digitally.

the woddler - lower "shutter speed" works BETTER in action scenes (check out Band Of Brothers [HBO/BBC Production] for the use of lower shutter speed during action scenes. i dont know why but it just does.

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a carefull man tries to dodge the bullets, while a happy man takes a walk!

[shirt]

Hold on, no no no.

FRAMES PER SECOND can never be altered for video, for film it can be though.

Before someone argues this...

When you adjust the frame rate, your picture quality will NOT change. However, the speed of which the tape/film is run at will. This is how you do slow/fast motion. The faster (the more frames per second) the slower the picture will move... and vice versa.

NOW!

The FRAMES/SECOND with PAL will remain at 25. However, you can easily adjust the shutter speed, to whatever you want. This will effect picture quality because the shutter speed is determining the amount of light which is collected by the camera, etc.

FINALLY,

FIELDS/SECOND can not only be changed in one way, and that is through deinterlacing your video. You see, video is presented in two fields (PAL has 525 lines)... this is what forms a video's resolution. Now, if you want to show a still image of a video frame, or you have an incredibly low shutter speed, the video must be deinterlaced in order for it to look clean.

Hope this helped.

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[tim.callaghan]

Going back to the PD150 though,

and the VX2000 too, will only shoot 15fps progressive scan (NTSC version, and presumably 12.5fps for PAL). Yes when it is played back, it has no choice of what rate it is played at as PAL and NTSC are defined standards, but it just means alternate fields will be displaying the same frame of one scan. For instance 15 fps progressive scan will equate to 4 NTSC fields displaying one frame, which is jittery. The Canon on the other hand offering although not technically true progressive scan, doing it at 30fps/25fps depending where you are will represent 1 frame with 2 fields, giving it a very rich movie like feel.

Tim

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