Making Lighting flashes (with a DSLR)

D

DDirector

Veteran
So, I want to shoot a mini short, or just some random sample footage just to throw on my demo reel to show that I at least create some great shots.

So, I have this one scene setup, but it requires flashes of lighting. The flashes should eliminate the entire room of the house through its windows.
But, working with a DSLR, it seems it will be a LOT harder than it seems because of that rolling shutter issue thing.

So, here are a few questions I have about lighting flashes:

1) How to create a lightning flash with a DSLR
2) Since I want to eliminate the entire room with a flash of light, what kind of lights would I need?
3) Its a dark setting. There is one character sitting in the middle of the room with a single night stand shining at him. How bright can the flash be?
 
I think your just gonna have to experiment, I cant see anyway to give accurate info. I can say this though. You may be better off doing a combination of the effect live and in post. You dont need something as powerful as a flashgun. Maybe just hitting power to a 2k with a 1/2 ctb. to create the flash from outside, do the same inside, then add in post. Sorry I cant be more helpful. Or you could do it simple and use a cam with ccd's
 
maranfilms said:
You may be better off doing a combination of the effect live and in post.
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I'm not much of a post guy, but how would you work this out in post? What would you even do? I'm pretty sure, since this is my personal project, I'll have to do the editing and sfx in post, so im curious

And usually lightning flashes arent just a single quick flash. Its usually like a flash followed by a few more smaller flashes, or something like that. They may even last longer or shorter.

A little bit off topic, but it may cause problems later, or help with thinking things out, but would lightning flashes be soft or hard light?
 
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Lightning, with an N

Lightning, with an N

There's a really low-tech way to do this...rig a window shutter in front of a light, and flag off the light on the sides. Operate the shutter like you're having an epileptic seizure. Switch the light on and off at the beginning and end of the lightning spell.

I augmented this effect in post by flickering the opacity on a white matte set to the "Add" blend mode...
 
Justin Kuhn said:
There's a really low-tech way to do this...rig a window shutter in front of a light, and flag off the light on the sides. Operate the shutter like you're having an epileptic seizure. Switch the light on and off at the beginning and end of the lightning spell.

I augmented this effect in post by flickering the opacity on a white matte set to the "Add" blend mode...
Click to expand...

This is really the best way to do it, actually the way its done. Turning the light on and off won't work, since halogen lights such as fresnels tend to "fade out" and in, its still fast enough to make you call striking, but slow enough to look fake. Find a small window shutter, rig it on a frame infront of the light and open and close it quickly.

A cheaper method would be just getting two small flags (12x18) and doing the same shutter effect with your hands.

Check this video out: http://www.youtube.com/watch?v=aeHCC8u1kE0
 
In post, you could split the clip and apply a flash transition. I used this to fake a vintage flash bulb going off and it worked quite well.
 
David Parsons said:
In post, you could split the clip and apply a flash transition. I used this to fake a vintage flash bulb going off and it worked quite well.
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Big problem with this is that you are essentially just increasing the brightness in the overall image, unless you mask, and even then you don't get the shadows you'd WANT to get from lightning. That post effect is better for flickering lights such as fluorescents in a hallway to enchance only, but you'd want to have the fluorescent fixtures flicker to make it look real

DDirector said:
Yeah, I prefer not to deal with it in post. Masking everything would be a pain, and won't look realistic.
What's the technical name for that lightning shutter that was in the video?

Ill have to contact the rental houses in Toronto and ask if they have such a thing.
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Just contact a rental house and tell them what you need, I'm not sure what I'd call it aside from a "flippy shutter lightning thing". They should point you in the right direction. Maybe they even have cheaper systems for lightning effects
 
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Yeah, I prefer not to deal with it in post. Masking everything would be a pain, and won't look realistic.
What's the technical name for that lightning shutter that was in the video?

Ill have to contact the rental houses in Toronto and ask if they have such a thing.
 
The thing is, if I use flags and do it by hand, won't it not be fast enough that you see the shadows of the flags? It seems like it will be... And if I rent the lightning effect for a big HMI, like the 18K or whatever it may be, won't I still have some issues with the rulling shutter? It would be simpler to shoot on a different camera, but I don't want to rent out a new one or look for someone who has one. This is my project, so ill be shooting on my gear, and don't want to be mixing cameras.

An 18K as seen in the video would be probably a good choice as I'd want to have the light outside, and it would need to fill a decently large size living room. It may be a tad too big. A 2K is probably the most I can take from a household plug, and I don't believe that is close to enough wattage. So, I guess I'd need a genny for the HMI. This was supposed to be just a small project, guess its turning out to be bigger more expensive now. Might as well, go a bit more full out then.
 
DDirector said:
The thing is, if I use flags and do it by hand, won't it not be fast enough that you see the shadows of the flags? It seems like it will be... And if I rent the lightning effect for a big HMI, like the 18K or whatever it may be, won't I still have some issues with the rulling shutter? It would be simpler to shoot on a different camera, but I don't want to rent out a new one or look for someone who has one. This is my project, so ill be shooting on my gear, and don't want to be mixing cameras.

An 18K as seen in the video would be probably a good choice as I'd want to have the light outside, and it would need to fill a decently large size living room. It may be a tad too big. A 2K is probably the most I can take from a household plug, and I don't believe that is close to enough wattage. So, I guess I'd need a genny for the HMI. This was supposed to be just a small project, guess its turning out to be bigger more expensive now. Might as well, go a bit more full out then.
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Pick up an Arri 1.8 HMI if you don't want to use a genny, since you can't pick up just ANY random generator to power a large HMI, I recall a normal rate for a genny to power a big hmi (4k-ish) would go for a good 200-250/day, not considering the hmi itself.
I dont think you should have issues with rolling shutter, since those blinds aren't THAT fast, and 18k would cost thousands to rent with a generator large enough to power that beast
 
I think thats where he will run into issues with rolling shutter. That was why I thought it may work better with less light and a slower speed. Just a thought, but it will have to be experimented with.


What I mean by doing it in post, would be to increase the overall exposure on certain items in the room for a split second, similar to the way we create flash from a gun. (not muzzle flash, but the hard spill caused from the flash, and the way it lights only parts of things) In fact Andrew kramers tutorial on muzzle flash would be a good place to start. Of course you would need to do it different, but with the same idea though is all im saying.
 
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sonofaresiii said:
flicker box. rent one, build one, there's guides on this here very site but i was always too dense to figure them out.
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So, yeah. There are currently 3 ways from which I have heard so far.

By hand; opening and closing flags quickly.
With the Arri lightning Effect gizmo
Or with a flicker box.

By the sounds of it, by hand may seem to bee too slow and may not look right. The lightning effect gizmo sound perfect, but its an additional rental IF there is one locally, a flicker box may just work as well too?
 
Having read the comments, and checked out that video, it seems like it'd be pretty easy to combine the flicker box and flag method into a DIY flicker box for the cost of peanuts.

I'd buy a sheet of black foam core (or black aluminum sheeting, if you have a way to cut it, it'd be less flammable.)

And make two of these things with it:

shutter.jpg

Then, mount the one to the light, and hold the second one in front, staggered so as to block all the light. Practice running it up and down to get the effect.

You could easily mount them together for more control, by cutting a running slot vertically about an inch and a half up and down (opposing direction to the light slots), along the two sides of the back sheet, and then putting a bolt, washer and nut through the front sheet to hold 'em together. Loosen it a bit to allow up and down movement.

I haven't tried it, and I might be missing something, but thought I'd toss the idea out there :)
 
Call up your rental company, and explain the effect you're looking for. They'll either be able to suggest things they have in store, or point you in the direction to where you might find such things.

Also, not sure why you'd need an 18k... Even if you're going for completely white - shoot on a DSLR and light the scene to f/2.0 (I assume it's night anyway, considering the lightning). Put a 2k right up against the window and you'll be sweet. Even if you only get the 2k to get you to f/11, that's still 5 stops over-exposed which a DSLR will struggle to handle, and even if it does you could increase the effect in post much easier than trying to do the whole thing in post. An HMI will give you better light output, but are also much more expensive to rent.
 
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