# loco fx?

Ok i know thets not going to be the name of it but that’s what i call it.

in the movies and in the tv shows now there is an effect that they do that can be done with just a simple camera all though it is sometimes done in post. I would like to recreate this using blender. So let me tell you how it is done with a regular camera and maybe you will know how to do it in blender, then tell me.

The numbers i will be using for footage are just numbers i picked. If i was doing this in real life i would have to set up an measure everything.

Ok set the camera up 20 feet from your main object and zoomed in tight. Start moving the camera forward ( with a dolly of course) while zooming out at the same speed, and stopping the whole thing about 5 to 10 feet from the object.

This makes it seem that the whole world is rushing in to your object not litlrley but you know what i mean. Thats why i call it the locofx.

Now i can do this with Blender I know i can but it may take me hours even days to get it right. Unless I have some spcific numbers and instructions. My question is has anyone recreated this and can you tell me how to do it?

i know what you are talking about.

i can run up some quick math if you would like.

Tan[(1/2) θ] == w/(2d)
if i solve that for d i get:
d -> (1/2) w Cot[θ/2]

and then
focallength = abs(aspectratio / tan[0.5 * hfov])

and i substitute in the first part, i get:
focallength = abs(aspectratio / (w/(2d)) )
and
aspectratio = width/float(height)
so
focallength = abs( (width/height) / (w/(2d)) )

try that. my math is probably wrong, but that might work. idk.

just parent the cam to an empty, move that on one axis using the math you get, and on those keyframes make a focallength keyframe too.

I know what you are talking about. Alfred Hitchcock used this technique.

I have done this in Blender before.

Change your your camera settings from 35mm to a higher level, in proportion to the zoom.

It’s called a reverse tracking or “trombone” shot, and as Spin said creates a very disturbing effect like in Vertigo. I have also seen it in Evil Dead and I think Jackson used it in Lord of the Rings. It takes a lot of coordination to execute manually but should be no problem in Blender. For a strong effect use a rich background with lots of depth cues.

You are going to have to adjust the lens distortion via Camera LENS IPO curves. With your Animated camera zoomed already established.

What I would do is, set frame 1 at exactly what you want. Adjust the camera lens to a very high mm, Like 200mm (then press the I-Key to set the IPO “LocRotSize”).

Go to the last frame and set the camera lens to 35mm and zoom in so it sort of looks like frame 1. It will be distorted. Again, press the I-Key to set the IPO “LocRotSize”).

Now you will have the ZOOM correctly, but the Lens mm didn’t get stored, so select the camera, and go into IPO mode and choose CAMERA from the Drop-Box.

Select Lens.

In the IPO editor, Press and hold Ctrl+LMB to create the Lens mm for Frame one. Go into Edit Mode in the IPO and Select the entire “dot” and Shift+D to duplicate and move that new “dot” to the last frame.

You’ll need to some adjusting (trial and error), but it will work.

I confused the heck out of you, but once you start playing around with it, you’ll get it.

I did this FX in v2.37a and it didn’t seems that complicated.

Well spin it worked great thanks!

This is actually fairly easy to do with blender!

go to frame 1 of your animation and set a key frame in the 3d window for the location and rotation of the camera
then set a key frame in the camera properties window for the “lens”

go to the end of the animation and move the camera closer to your subject
(“G” then middle mouse allows you to dolly in)
set a keyframe for loc + rot
then go to your camera properites and set the lens to something smaller like 15 or 20 then set a lens key frame.

Alt+A

edit: D’oh! when I started this response, It was the only one, but I got called away. Oh well, that what’s great about elysiun, lots of people have the right answer!

Interesting effect. I remember the effect was also extensively used on “The Quick and the Dead”. The suggestions on how to do it in Blender were very useful.
BTW, does anyone know what the parameters Apert and FDist does on the camera IPO? There seems to be no equivalent buttons for them on the buttons panels…

I believe Yafray can access the Apert and Fdist values for Depth of Field calculations.