Formula For Filming Miniatures and DV Camera question
Formula For Filming Miniatures and DV Camera question- special effects and filmmaking
OK..I read this in an ILM book and have a question of whether this can be done with a consumer DV camera. (variable framerate) If so, which cameras can handle this, or is this only possible with film cameras?
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**AOL IM - EyesRMaced**e-mail - dedhorse@ev1.net
[This message has been edited by Wade (edited 01-21-2001).]
this formula is used to find out how fast to crank a film camera. in your example, 76 frames per second. as of now there's only a veerry expensive video camera that will limitedly do the same thing.
I'm no expert on the subject but if I had to shoot the spaceship in your example, the first thing I would do is adjust the formula by using 29.97 instead of 24 since video (NTSC) has a frame rate of 29.97 frames per second and not 24 FPS as with film. Also, your formula seems to be designed for a static camera since it doesn't consider distance travelled
Next, since I don't have a high speed camera I would opt to shoot the model using a "poor man's" motion control rig. I built one of these when I was young and shooting super 8 film. Basically, I built a dolly on a track so that I could rest a tripod with a camera on it. The track was simply model railroad tracks mounted on a piece of plywood. The dolly was basically some model railroad cars mounted on the bottom side of a piece of plywood. I attached a popsicle stick to the plywood dolly so that it pointed down to the plywood base that the railroad tracks were mounted on. I marked off the plywood base in half inch increments. This way I could move the dolly a half inch at a time by pushing the dolly to the next half in mark. Then I would snap a picture and advance the dolly again.
Now, you don't need the formula that you spoke of since you will be shooting in single frame mode.
You need to know how far your camera is going to travel while shooting this "stop motion control". Lets say, for the sake of simplicity, that you are going to shoot 30 frames per second (29.97 rounded to 30) and you are going to have your camera travel 10 feet and you want the shot to last for 2 seconds of screen time. OK, 2 seconds means that you will have to expose 60 frames (29.97 rounded to 30 frames per second x 2 seconds=60). Now, 10 feet of travel equals 120 inches or 240 half inches (remember, we made 1/2 inch marks on the plywood). So how many frames do we have to shoot for every 1/2 inch mark? 60 divided by 240 which equals .25. You will have to expose a quarter frame or .25 frames of film (video) for every half inch mark. Since we can not shoot a quarter frame we simply add them up until they equal 1 whole frame. Simple math tells us that there are 4 quarter frames in one whole frame so 4 quarter frames also equal 4 half inch marks. 4 half inch marks equal 2 inches so you will shoot one frame for ever 2 inches of dolly movement. You will snap a picture then move the dolly forward 2 inches then snap the next picture then move the dolly forward again and snap another picture until you have snapped 60 pictures and travelled 10 feet.
This really does work but the problem with it is that you will get no motion blur. There is a solution if you have After Effects. You can use a motion blur filter that will artificially create motion blur on the video. You can set the parameters on the filter to have as much or as little blur as you like.
If you want to get really creative you can also calibrate your tripod so that you can pan as the dolly moves. It's just a little more math.... Special effects are so cool!
[This message has been edited by morpherguy (edited 01-21-2001).]
great tip, morpherguy!
yes, very cool indeed. morph, have you ever used any of the servo control boards for computers? i was thinking about this before...if you could calculate the scale speeds things had to happen at, could you program the board to ove things that fast? that way all you'd have to do is replay the actions and film as is, more math intensive at first, but less room for error while filming. i'd love to have a motion control rig and camera that would do it though
somedaylater
TOm
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What everyone seems to forget is that once we look past race, religion, gender, and all that, everyone on this planet is first and foremost...
...a PERSON
Wow! way to go morpherguy! Give that man some karma, someone!
Y'know one of the few drawbacks of LAS is that sometimes when I read stuff that people are doing, stuff that people have worked out, solutions people have come up with, it makes realise that I'm not really very smart after all.
Morpherguy...once again...way to go! Thanks for the tips.
B Rhomboid: I know exactly what you mean...sometimes I feel like the dumbest, most uncreative guy on this board....
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