The "Stretching" effect

[Guest Daniel J. Ashley-Smith]

We are all aware of the effect produced when zooming in or out a super long focal length lens when shooting motion. Probably seen it in "Jurassic Park 3", "The Mask" and "Lord of the Rings", brings the background closer and makes them look as though they are standing right next to a close up object.

 

(YES this is exactly what I was getting confused with depth of field)

 

But, what focal length is needed to create a noticeable effect?

 

Any comments appreciated :)

[John Pytlak RIP]

Perspective and telephoto lenses:

 

http://www.ski.org/CWTyler_lab/CWTyler/Art...ctiveRules.html

 

http://www.findarticles.com/p/articles/mi_...y_1/ai_76806339

 

http://www.cinematography.net/Pages%20DW/5...OnS16mm35mm.htm

[Guest Daniel J. Ashley-Smith]

Umm, I probably didn't explain it very well. I'l upload a short movie clip on the internet for you to see.

[Guest Daniel J. Ashley-Smith]

http://www.geocities.com/djasmirror/cine/example.zip

 

WMV format.

 

Had to stick it in a zip folder because the mongs from geocities think wmv isn't a valid format, i.e. if it isn't in their lists it's not valid... What crap...

[Sam Wells]

Are you reffering to what's often known as the "Vertigo shot" ? (after use of it on the Bell Tower in Hitchcock's Vertigo ?

 

Zoom out track in simultaneously in the case of "Vertigo" but if you do it vice versa it

sounds like what you are describing....

 

-Sam

[Guest Daniel J. Ashley-Smith]

On that movie clip, it's the bit when he looks over to the next platform but there?s a gap and the effect really emphasises it. Makes it stretch so it's even further. The focal length of the lens is decreased by zooming out. And instead of making it look like a standard zoom, it has a weird effect. Trouble is, what focal length in a lens is needed to get the effect. My Dad reckons a 300mm but then again that's in photography. I'd say more a 1000mm.

[David Mullen ASC]

Sounds like the Vertigo-type dolly-zoom combo. So there is not a single focal-length involved.

[Mike Panczenko]

Yeah, as Mr. Mullen said, from what you are describing it is what's known as a dolly zoom, or push/pull. What you do, is you have a camera on a dolly with a zoom lens, and zoom the opposite way from which the dolly is moving. If you want the background to crash into the foreground, you dolly back while zooming in. If you want the background to move away from the foreground, you dolly in while zooming out. Hope this helps!

[Guest Daniel J. Ashley-Smith]

Ah ok, thanks a lot guys. :)

 

Umm, just one other thing, whats a dolly?

[Guest Daniel J. Ashley-Smith]

Actually never mind, found out.

 

Thanks again guys, it's appreciated.

[Marc_Abernathy]

haa.. yeah thats a cool shot. did hitchcock"invent" this ?

 

i was doing this eons ago with a little 8 millimeter camcorder(after i saw it in some movie). just walking backwards away from the subject whilst zooming into the subject. simple.