Of Giants and Miniatures

[Joe Giambrone]

Hello,

 

I've been talking to various DPs about how they scale images, and have found various formulae for this regarding frame rate, distance, etc.

 

For example, a 1/12th scaling you shoot the sqrt 12 * framerate (24) to arrive at 83 fps for a desirable upscale (slowing) of the element you want to look 12 times bigger.

 

Are there people here who have actually done this in practice on professional shoots?

 

Can you elaborate on the dirty details involved in making it look as real as possible?

 

It was suggested to shoot 10mm focal length for the scaling, as you get a lot of depth of field.

 

In matching the small blown up object (in front of a green screen) to the background plate, I am very concerned with a similar field of view and depth of field characteristics. Those would seem to be the hard part of the deal.

[Jim Keller]

I've only ever done miniature work for still photography, so I can't address the frame rate issues, but for still photography I'm not a fan of using shorter lenses for models. Audiences perceive the fisheye and it feels like a model. Rather, I prefer to use a longer lens with lots and lots of light (improving my depth of field by letting me use a smaller aperture).

[Chris Keth]

I have to agree with the disapproval of using wider lenses. Use the lens to achieve the perspective and angle of view that you want. Then light to the stop that will give you the depth of field you want. That will look more convincing than going much wider on the lens.

 

As for the framerate, that is the same "rule" I have heard. I have never tested it myself, though. I know there are quite a lot of books about Ray Harryhausen's work and about the effects work for Star Wars. Perhaps you can find some good answers there.

[Stephen Williams]

I have to agree with the disapproval of using wider lenses. Use the lens to achieve the perspective and angle of view that you want. Then light to the stop that will give you the depth of field you want. That will look more convincing than going much wider on the lens.

 

As for the framerate, that is the same "rule" I have heard. I have never tested it myself, though. I know there are quite a lot of books about Ray Harryhausen's work and about the effects work for Star Wars. Perhaps you can find some good answers there.

 

Hi,

 

The framerate formula works fine, I have used it many times. I use the same lens for scale models & full size, then you can move the camera with a motion control rig doing a matched but scaled move.

 

Stephen

[Leo Anthony Vale]

I've been talking to various DPs about how they scale images, and have found various formulae for this regarding frame rate, distance, etc.

 

For example, a 1/12th scaling you shoot the sqrt 12 * framerate (24) to arrive at 83 fps for a desirable upscale (slowing) of the element you want to look 12 times bigger.

 

Are there people here who have actually done this in practice on professional shoots?

 

Can you elaborate on the dirty details involved in making it look as real as possible?

 

quite awhile back, I came across a circa 1930 SMPE Journal ( the T for telvision had yet to be added)

in which it was shown how that formula for miniature speeds was derived from the formula for the speed of falling objects based on gravitational acceleration. Unfortuneately I can no longer remember the proof.

 

Certainly use the same lenses that you would use for the live action, else the miniature shots will stick out. Unlike the other responders I would use wide angles for both.

Suppossedly michael Chapman has said that long lenses are "...elitist, immoral, and possibly even corrupt".

 

Adding atmospheric perspective (haze) will help, a light diffusion or fog filter or a lot of cigerette smoke will help.

[Joe Giambrone]

Thanks for the answers.

 

"Adding atmospheric perspective (haze) will help, a light diffusion or fog filter or a lot of cigerette smoke will help."

 

It on the water, so there will be some water spraying involved.

 

Is there a web depth of field chart where I can study the various field of view and aperture possibilities?

 

I may use pretty wide lenses for both the small and large, but I don't want to be locked into that configuration for all those shots.

[Jim Keller]

Thanks for the answers.

 

"Adding atmospheric perspective (haze) will help, a light diffusion or fog filter or a lot of cigerette smoke will help."

 

It on the water, so there will be some water spraying involved.

 

Is there a web depth of field chart where I can study the various field of view and aperture possibilities?

 

I may use pretty wide lenses for both the small and large, but I don't want to be locked into that configuration for all those shots.

 

I use the depth of field guides published by the ASC. Remember, though, that the "same" depth of field on different length lenses does, in fact, have a different look, so I suggest testing to be sure you like the result (you can do this on a still camera with the same size chip as your production camera / same size negative as your production camera) before doing the full production.

 

You'll want to use more mist than you think you need, because the audience will perceive the mist as atmosphere first and mist second. Bear in mind that water doesn't miniaturize well, so, again, you'll want to run tests.