Speed changes - New theory ... me and my theories

[TimurCivan]

OK you guys, in my ever lasting quest to figure out how to get the most from thsi machine i have ANOTHER theory that seems to work!!!!

i was watching el mariachi. there is one scene where the main charachter goes into a hotel. and the desk clerk dives for the phone to call for help. but the speed of the scene changed during the shot. it just suddenly sped up. so i was thinking how can i do that. so i shot a test, and when i sped u the clip, it lookd unnatural too jerky. then i figured out you can change shutter speed on the fly while recording. so at the critical point i hit the speedselect button, and it jumped form 1/48 to 1/24, and in editing , you just use the frame where it lightens up one stop, as your marker for when to boost the speed to 200% then reduce the brightness to match the previous segemnt of the clip. voila! it looks great! try it!!!!

I cant post footage i have nowhere to host. but its just a cool effect.

PS: Great for making zombie lunge attacks happen faster..... just get the attackee to act a little slower asa the zombie lunges in realitme. it really looks like the zombie goes from Romero's Dawn of the dead, to 28 days later infected in an instant.

 

[Rasquachemedia]

funny, i just finished watching el mariachi. first time since it first came out. the real treasure of the dvd is the director's commentary.

Rodriguez mentioned that for some shots he would shoot at slower or faster frame rate to get a certain effect or smooth out some of the camera shakes.

Can't remember what he said about that shot.

I'll try out your theory and let you know how it worked. I know you can also change the frame rate in the camera a bit as well. They go over that in Barry's dvd.

but it seems like your idea is something that can be done on the fly. I figure color correction would be needed to make it look continous.

 

[Jarek Zabczynski]

I like that a lot, I will give it a try. Thanks.

 

[PDX_DVX]

You could maybe even leave the brightness in in certain situations, to give it sort of the film rollout look, as in Man On Fire...

 

[Policar]

That's really very clever, actually, since maintaining the ratio of shutter speed to frame rate is very important in getting acceptable slow motion. I may try that some time.

As for shutter speed changes on film, it's all undercranking/overcranking so it's done by hand. Wow does it look cool, though. I don't know how an even level of exposure is maintained, however.

 

[PDX_DVX]

I love the look of the different frame rates and speed changes in film. I guess in Man On Fire they used a hand cranked 35mm cam, and constantly undercranked/overcranked the footage in certain shots, giving it a gritty, jumpy flashy look. Very cool. I have never even thought of using the shutter speed button during the shot tho, I'll have to do some experimentation with this technique!

 

[dudeguy37]

I don't know how an even level of exposure is maintained, however.

What's up Policar and Everyone-
Here's my tiny bit of input real quick. I was at a film progam this summer where I shot film (16mm) for the first (and hopefully last, but that's a whole other story) time. We used the same camera that RR used on Mariachi (Arriflex S). A few of my friends and I tried the speed change on the fly. Basically what you have to do is rack the intervalometer either faster (making a slower picture when played back) or slower (making a faster, but jumpy play back). The key here is that you have to rack aperture as you rack the intervalometer. The reason for this is that if you're film is running through 2x as fast you'll have only half the light per frame, therefore you would need to open up a stop i.e. f8 to f5.6. The same goes for slowing the film rate down, because each frame will get double the light, so you want to stop down i.e. f11 to f16.
The trick to this whole process is getting the aperture and intervalometer rack to match up, and for the camera not to shake. It ain't easy, but it's do-able, and of course if there's one guy who'd do it it's Rodriguez. Hope some of this helped.
Peace,

-Harry