Welcome to our community

Be a part of something great, join today!

Log in
  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Long duration flash bulbs with gradual roll-off for rolling shutter camera

M

Matt W.

Well-known member
Joined
Oct 3, 2009
Messages
1,350
Reaction score
1
Points
38
I want to shoot a few scenes with camera flashes bursting in slow motion onto the subject. Rolling shutter is an issue.


In the past I’ve used actual physical flash bulbs or mechanical shutters on hot lights, but I want a lot of flashes going at once. The scene is a photographer in a studio. Or outside a premiere. I want it to appear stylized… they linger for a frame or two. Actual camera flashes are plenty bright, but they strobe and do not last very long. I want the impression of slow motion flashes even though I'll be shooting mostly at 24fps or 30fps for 24fps... not distinctly slow.


What are my best options. Are there any flashes that fade in and out? HSS flashes? Old pack flashes? I want something that lingers for a frame or two and fades out softly. Maybe actual flashbulbs might be the thing… just have to get it in a few takes.


Thanks!
 
Last edited:
You might also experiment with adding the flashes totally as a visual effect or as a color-correction. I'd much rather have a full-screen flash (or at least a 2- or 3-frame gradual fade to clipped white) with zero rolling shutter artifacts than the real thing. It's hard to correct out that half-screen (or partial screen) flash problem.
 
Best to use a camera with a global shutter. Easier and always looks better.
 
You may use a motion mount as already suggested or if not available get a radio trigger and sync the strobes to your shutter via the sync port on the side handle. You can map a button on your camera to open the flash. In general all modern strobe equipment is optimized to a short flash duration, if you want a "longer flash" you might use and old "big" pack and attach a single lamp to each unit, dial down the power to min will give the longest duration. Be careful with older units, a lot of these will have high tension on the sync cord, don´t wire them directly to the port of the side handle.
If you can get hold of a broncolor Grafit A4 and a Pulso 8 head and connect this head to port 3 you will achieve pretty long durations. We played a bit with our strobes and with and without rolling shutter effects, works pretty well:

http://www.reduser.net/forum/showthread.php?123926-Played-around-with-Strobes-for-this-Hair-Shots

Cheers, Ulf
 
Easiest cheapest thing is to use flash bulbs. I use them all the time for gags. I made up a piece of aluminum with 5 bulb sockets in it for peanut bulbs, and wired it to a nail board. If you wanted more, you could ire up a board or a plate with as many as you want. I also use the edison base sized flash bulbs screwed into a single lamp fixture and triggered by a switch. Make sure you have a solid ground, 3 volts will set them off, and any leaky voltage will make them pop and they aren't cheap.

Kress photo has them and flash guns etc. - http://www.flashbulbs.com/index.shtml

nick
 
Thanks, everyone. The motion mount is obviously the right choice for most of this stuff (Ulf, really cool video, btw... pretty close to what I am going for in some ways, although obviously there are motion artifacts but not substantial) but I want the flashes to feel a bit slow. Almost like this:

https://www.youtube.com/watch?v=HAfFfqiYLp0&t=2m7s

Those look interesting:

http://www.meggaflash.com/meggaflash-bulbs/flashbulb-slow-peak-pf300

The light lasts for as long as 60ms it seems like... so at 24fps you might get two frames exposed.
 
Again, I'm equally concerned with trying to get strobes that have a slightly longer duration and softer flash to simulate a slow motion feel even though we'll be shooting between 24-60fps...

The motion mount does seem like the best option in general, but I want the long flash duration with a softer fall-off, too.
 
Everything you are describing. Flash bulbs do. They last about 2-3 frames with a soft attack and decay.

Nick
 
Nick Gardner said:
Everything you are describing. Flash bulbs do. They last about 2-3 frames with a soft attack and decay.

Nick
Click to expand...

Thanks. We only have a few set ups so even though these might be more expensive in the short run, they're probably cheaper overall.

I've used flash bulbs before but I think they were some older brand and blue dipped. I like the blue dip to bring the color temperature up to something more manageably blue. It seems some flash bulbs are 3800K, which is too high.

Can you gel flash bulbs and retrofit them to fit in a softbox? Would they be punchy enough? Is there any way to gang them up through a soft box for that purpose?
 
I would think led intelligent stage lights can be programmed to simulate a strobe effect with lots of decay. Not sure how you would fit them to a softbox though.
 
If you buy #31 flash bulbs, they are eddison based, and you can do what you want with them. You could put them in a chicken coop style softbox. Color temp is tungsten, if you want daylight you can get them with a blue coating, or gell to taste. Punch is relative. If you want them to overpower daylight, that's a tall order, but if you are interior lit to a 2.8 at 800 iso, they have major balls.

Here's a link to some 31s -
http://www.ebay.com/itm/GE-31-Super...995?pt=LH_DefaultDomain_0&hash=item41919ba18b

Nick
 
Brilliant. How do you fire them? It says operating voltage 3 to 125 volts....

Can I fire them just by plugging them into an edison receiver and turning a switch on (plugging the light in of course)?

Or could I fire them via 12v car batteries even outside? I do want to do a couple set ups in the sun... basically anything above 3v will cause them to fire? There's no capacitor or anything?

So they can be fired simultaneously by all being plugged into one place? In the studio set up I want to emulate strobes firing in unison... so if I could fire these in unison ganged up in soft boxes.... brilliant.
 
Yes to everything you just said. You don't even need a car battery I use lantern batteries. I hve also used them screwed into edison bases with cords going into a magic gadgets flicker box so we could program exacly when they went off. You can use them outside, just lose the diffusion and get close. I'd order some and test. Ebay is a good source if you re not in a hurry, and flashbulbs.com is expensive but prompt. They are also really nice nd will answer any questions you may have.

I have used theses specialized flash bulbs before, thy are really big, and burn for 2 and a half seconds. They were desgned to light car interiors durring crash tests at extremeley high frame rates. Thos are good fun to play with. I used them for practical light gags on explosions that will be added later.

Have fun.

Nick
 
You must log in or register to reply here.
Back
Top