Moving through glass

phoenix_dark

phoenix_dark

Member
Does anyone out there know how to shoot/edit a shot that moves through a window/glass? I have some ideas of my own, such as; using a dolly and doing the shot twice exactly with/without the window. I plan on doing the glass/ripple effect between the cut to mask (hopefully) any jumps. I want to know what all you think though!

A great example for what I'm trying to do is in the third Harry Potter movie in the very beginning. Thanks
 
I've always wondered about this one myself.

One possible method I just thought of is ridiculously simple:
Mount the glass so that it moves with the camera for the first part of the shot, then as the camera passes the plane of the window, leave the glass (this is the tricky part) into the frame from behind and continue the camera move.
Just one possible solution.

How big is your transition effect? You might be able to slide in a very clean sheet of glass as the camera passes and use a transition - or even a shallow DoF with the glass very out of focus - as you pass.

- Mikko
 
you could technically shoot the whole dolly shot w/o glass and then add the glass/wall/whatever in post .. just put some greenscreen/bluescreen behind the glass and shoot the outside part that way .. the only thing to worry about would be doing the dolly and having your camer with the same focal settings so it doesnt look weird when you composite
 
How are you going to film that first part 'with the glass' without reflections showing the camera itself?

I'd say dolly without any window, then add a window reflection in post. (as said above)
 
My thought of how I'm going to do this is similar to Mikko's idea. The window is going to be suspended in air by cables from the ceiling so I can do the dolly shot with no window what so ever then do the exact same thing and have two people lower the window in front of the camera as I pass and I take the cut in post when the window is completely in place using a transition (:20?). I did think about adding the window in post by chroma keying it but I don't think I could get a clean key being that I'm shooting through a window and I want the slight distortion of picture a window gives. A key would just cut everything out.

That's a good point about reflection though Meta I'll have to take that into consideration no matter what I do
 
Check out the BTS to Bad Boys II. They show how they did that shot. I believe the glass they used was CG and they just moved the camera through an opening
 
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One way to see movies without buying them...


- Mikko
 
Glass

Glass

Hi Phoenix,

Depending on what kind of window you are using, you could shoot up to the glass, open the window, and continue the dolly out the window. In post, a quick cross dissolve from one shot to the next could mask the cut a little. Could you post a photo of the window? Much depends on what kind of window it is, how it open/closes. It also depends on your needs with the shot, and if you don't mind a slight dissolve.

I did a lovely shot like this 10 years ago through iron bars. As the camera approached and passed the focal range of the iron bars, an assistant pulled them (made of wood and painted black) away from the windows and the camera performed a dolly straight out the window on a make shift 2X4 with camera mount screw. It turned out quite nice, albeit a little different than what you are doing here.
 
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I'de do the entire thing in post, providing the dolly shot is fairly consistant. For reflections the camera would see you take a picture looking out the window, and put it back into the footage as the "glass" layer. Then use a blending mode like Screen, Linear Dodge, and scale to match. when you go "through it", blur it and the background footage for 3-5 frames and drop the opaicty of the glass layer. Plus motion tracking and corner pinning would help keep it in place and would scale for you.
 
Silent Hill

Silent Hill

In the motion picture, silent hill, they use a similar shot. The camera booms up from street lever and enters through an OPEN window and then into the bedroom toward th characters etc. It was a beautiful shot and i remember seeing it and saying how well done it was.

Obviously the jib arm can't be this long or articulated, so they took the sequence in two shots.

1. The booming up from the street and toward the open window.
2. From the open window into the room.

The trick they used involved the exposure of the window. Trucking into the window, the window opening into the room was dark enough so that when the frame was filled, they could cut to the next shot and bump up the iris. The transition looks like 15 frames mix where they mixed the last and first frames of the two shots to make it look like one fluid continuous take.
 
i have that creative cow dvd.. it's good.. but not "that" good. and it doesnt really exactly have an overview of the effect ure trying to achieve.. but maybe it does.. but im 80% positive it wasnt there.

the professional way of doing this is by just shooting the scene without the window or glass to avoid the troubles of unmatched timings of video, or change in light temp. or anything like that for that matter.

1. shoot it without anything.. whatever you want to go in.. yes shoot it without the glass.
2. take dimensions of the glass, take a picture of it if uve got a cam.. of its texture.. engraving.. whatever.
3. get into 3d application.. or photoshop or whatever you want to use to make your window. i use max 8. i'd make the glass.. give it a slight bumpy surface with some refraction.. make the environment color blue. save 3d model. (no animation yet)
3. now load the videoshot in camera tracking application.. here are some pro apps for that: bojou (high end), syntheyes (cheap but awesome), and PFtrack (which is what i use). choose four or more points (the edges of the window).. track. export camera tracking info.
4. go to compositing app.. load camera tracking info. make a mask of 4 vertices or more depending on the shape of the window. assign mask vertices to camera tracking points. also add a blue background layer.
5. back in max.. or ure prefered 3d application.. add masked video to glass material as diffusion to simulate the environment being behind the glass.
6. in 3d app.. load camera tracking data. adjust - move - rotate the window or glass according to the edges of tracking data. go into camera viewport. hit f10.. and render baby. ( we already chose the blue environment for later)
7. get into your compositing app. video element. with the rendered element on top. key out the rendered element's blue area. make key frames for dissolve or the effect you like. render composition.
(8.extra. make a new composition in the same project. put the last composition in the new empty composition. add motion blur. color correct.. do ure thing.)

hope this helps. you can tweak it to your liking.
 
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