Creating shafts of light - Page 2 at DVinfo.net

Go Back   DV Info Net > The Tools of DV and HD Production > Photon Management

Photon Management
Shine an ever-loving light on you.


Reply
 
Thread Tools Search this Thread
Old February 13th, 2007, 04:29 AM   #16
Regular Crew
 
Join Date: Dec 2005
Posts: 189
I would like to create this effect for a church like scene where the speaker is at the pulpit. The speaker would be lit (would love to get that angelic shaft of light) and everything else would be in darkness.

Problem: is it possible to create a similar effect with a single open faced light (500w)? Maybe light the subject from overhead and close down the iris?

Thanks
Joe Riggs is offline   Reply With Quote
Old February 13th, 2007, 07:35 AM   #17
Inner Circle
 
Join Date: Sep 2002
Location: San Mateo, CA
Posts: 3,840
An open faced light will not give you the 'shaft' that a focussed instrument will. You CAN put a 'snoot' on an open faced light. (Technically, it no longer becomes 'open'... but that's semantics)

A snoot is a metal cylinder that concentrates the light into a circular(ish) spot. The longer the snoot, the tighter the beam. It's NOT as effective as an ellipsoidal, say, which uses lenses to focus the cohesive beam, but if it's all you've got, it's all you've got.
Richard Alvarez is offline   Reply With Quote
Old February 13th, 2007, 11:21 AM   #18
Trustee
 
Join Date: Mar 2002
Location: Ann Arbor, MI
Posts: 1,327
You really need an Source Four or other ellipsoidal and a haze machine.
__________________
Jacques Mersereau
University of Michigan-Video Studio Manager
Jacques Mersereau is offline   Reply With Quote
Old February 13th, 2007, 11:39 AM   #19
Major Player
 
Join Date: Dec 2002
Location: Northridge Ca
Posts: 734
Besides the problem of focusing your open face light, that Richard points out, you are lacking serious firepower with only a 500 watt light. But there is another problem.

Light is not seen as a shaft unless you use smoke, which opens up another problem. (You can also use "Fuller's Earth, except it's a health hazzard) There are various types of "smokers" available, as well as solids that emit tremendous amounts of smoke when they are ignited. Just sit back and wait for the smoke to fill the church with a soft haze. Keep all doors and windows closed and you are good to go, if you have a suitable lighting instrument that will create the shaft and light the subject from a distance. As Richard mentioned, an ellipoidal like a Source 4 JR would be a good possibility, if you can rent one. They are pretty cheap to rent, and a purchase runs around $200.00. It's a great light to have in your kit. But I have a hunch you don't want to do that.

The other viable alternative is to create the shaft of light in post with software. One such software is 55mm (from Digital Film Tools), which has a "light" setting which could do this nicely. To prepare your footage, you should shoot the interior with the background barely visible and your subject lit normally. Later in post you create the shaft effect, which will then overexpose your subject as well as create the shaft. This method means the camera must almost certainly be locked off to create the effect.

Good luck
Wayne Orr, SOC
Wayne Orr is offline   Reply With Quote
Old February 13th, 2007, 02:59 PM   #20
Major Player
 
Join Date: Mar 2005
Location: Neenah, WI
Posts: 547
Quote:
Originally Posted by Wayne Orr
To prepare your footage, you should shoot the interior with the background barely visible and your subject lit normally. Later in post you create the shaft effect, which will then overexpose your subject as well as create the shaft.
Hi Wayne...long time.

One question...I have the 55mm package, but wouldn't you want to light the person from the top to create the proper face (and general down-) shadows? It might save some time in post to have only to add the shaft and not the shadows...

Or I might simply be misunderstanding you and I'm simply repeating your advice...
Tim Kolb is offline   Reply With Quote
Old February 13th, 2007, 03:14 PM   #21
Major Player
 
Join Date: Mar 2006
Location: Los Angeles
Posts: 439
Technically you can create shafts without any haze/fog (like laser beams) but we're talking serious light levels. All the recs. about Source 4's are good calls - you can't get that kind of output that tighly controlled for that amount of money any other way. They are EXTREMELY efficient fixtures. Also, if you're looking for more output but still on household current, K5600 makes an attachment to mount their jokerbug line to the Source 4's, giving about 4-times the brightness. That's a LOT of punch - it shouldn't take a whole lot of fog, etc... to make the beam stand out. Also know that fog acts like diffusion, so no matter how tight your beam is, expect some radiance and bounce from the beam itself. Also, if you're planning on using the beam itself to light your character, be aware that the beam willbe MANY stops darker than the pool of light at the end of it. DV/HDV/HD may have a hard time with that kind of contrast. You could aim the beam from above, to land just behind your character, and light the character separately... Or get a gobo that scrims just the very center of the beam, and make that part land on your actor. Since the camera is looking at the side of the beam, the effect will be invisible, but the talent will be better balanced with the luminance of the shaft. Source 4 (and all ellipsoidals) have gobo slots, so doing this should be no problem.

G'luck!
Jaron Berman is offline   Reply With Quote
Old February 13th, 2007, 03:27 PM   #22
Wrangler
 
Join Date: Dec 2002
Location: Mays Landing, NJ
Posts: 11,542
Quote:
Originally Posted by Jaron Berman
Also, if you're looking for more output but still on household current, K5600 makes an attachment to mount their jokerbug line to the Source 4's
These look very cool... am going to have to find an excuse to use them sometime :-)

http://www.k5600.com/products/bugabeam/index.html
Boyd Ostroff is offline   Reply With Quote
Old February 13th, 2007, 07:11 PM   #23
Major Player
 
Join Date: Mar 2004
Location: Pacifica, CA
Posts: 348
There are some gotcha's I can see when doing this 'live', especially on a small budget with little gear. Controlling the shape of the cone, rigging the light high enough above the talent/scene, controlling spill as well as light ratios if the 'shaft light' is also creating rim lighting on the talent, etc. It can seem so easy, but to do it well...
Eric Lagerlof is offline   Reply With Quote
Old February 14th, 2007, 12:51 PM   #24
Major Player
 
Join Date: Dec 2002
Location: Northridge Ca
Posts: 734
Wow. This thread has gotten pretty sophisticated and filled with great ideas.

Tim, you rascal, you have unmasked me. Yes, in a perfect world, that light source would want to be rigged above the preacher, but as Eric rightly points out, we'd be getting into some serious lighting and rigging to pull that off. My suggestion is a compromise that Joe might be able to pull off without too much pain and expense. And btw, that idea of Jaron's of using the joker with the source 4 is excellent, and I'm going to have to try that sometime. But for now, I'm assuming that Joe doesn't have all these tools available (or maybe the cash) for rent where he lives. So I suggest the software solution, but that's because I already own the 55mm software. Here's another way to proceed without the software or the expensive lighting hardware.

Shoot the wide shot with dim lighting in the church with the preacher in the pulpit. Light the preacher with the available 500watt light, keeping the light source out of the shot. The addition of candles, if appropriate, would add to the effect. Lock off the camera. Keep the light on the preacher off the background and probably off the front of the pulpit. Putting a source window for the shaft in the shot might help sell the effect.

Find an old aquarium tank, or something similar. Hang a piece of black material (duvetyn, if available) behind the aquarium. Back light the aquarium with the 500w light, fill the aquarium with smoke to desired volume, put a lid on the aquarium, and shoot it with your dv camera.

In post, you will layer the smoke over your locked-off shot of the preacher. You can cut a matte to give the smoke the proper size and shape, and maybe rotate the matte to an appropriate angle. Tweak the video levels to create the proper look, and soften the edges of the matte. The tricky part here will be overlaying the preacher without eliminating him with smoke.

Or, use the software approach I mentioned earlier. You can also use a "fog" filter from the 55mm set to give the church a haze look, besides the light shaft. Easy does it on these effects.

Or, rent a Xenon follow spot and rig parallels outside the church to place it on and blast it through the window into a smoke filled church. Shouldn't cost more than a couple thousand dollars, and your friends will be really impressed. :)

One additional thought: if you have the lighting fixture in the shot, you can eliminate it in post if you shoot a second locked-off pass of the same frame with no light and no preacher. Cover the light fixture in post with elements from the second pass.

Good thread. Let's see if we have some additional ideas.
__________________
Wayne

If it was easy, they'd get a relative to do it.
Wayne Orr is offline   Reply With Quote
Old February 14th, 2007, 07:56 PM   #25
Major Player
 
Join Date: Mar 2004
Location: Pacifica, CA
Posts: 348
Many 3D programs have "Volumetric Lighting" that allows for great control over the look of the shaft. Still the same issue with Mattes. You could shoot talent as Blue or Green Screen with some good rim lighting which would help remove spill and blend in the Shaft of Light if it was envisioned as being focused actually on the talent. More involved in post but you would only have to matte still elements, i.e. the podium and other foreground elements.

Assuming After Effects or some such app with at least decent Chroma Keying, shoot scene without talent, shoot talent green screen and render volumetric lighting with alpha, say as QT with 'color +' or PSD with alpha still sequence. Seperate scene foreground and background with matte into two seperate layers. Pre-comp volumetric lighting and background scene, Chroma Key Talent over that 'background comp' and top with matted foreground scene elements. Spice with levels adjustments and serve fresh.

It's a bit complicated and the green screen needs good, even lighting. OTOH your not matting moving talent and you get tremendous control over the 'lighting', whether live or in post, of the different elements.
Eric Lagerlof is offline   Reply With Quote
Old February 15th, 2007, 01:10 AM   #26
Regular Crew
 
Join Date: Feb 2007
Location: Brooklyn NY
Posts: 128
You can rent a 750 watt elipsoidal with a 10 degree barrel for 15 dollars a day. Anyone ever see the special features to Jay and Silent Bob Strike Back where the talk about the CG sheep that cost 50 G's.
Charles Hurley is offline   Reply With Quote
Old February 16th, 2007, 07:06 PM   #27
Regular Crew
 
Join Date: Dec 2005
Posts: 189
Hey guys thanks for the ideas, these are awesome. I think that software might be the way to go, this will be shot in a garage with a black background.

Wayne I was playing around with the light effect in the demo version of 55mm and found it hard to create the shaft. Could you post some basic instructions on how to create it.

Furthermore, you can create like a reflection window effect, it looks pretty cool on their site. What would be the best way to implement that.
Joe Riggs is offline   Reply With Quote
Old February 18th, 2007, 11:19 AM   #28
New Boot
 
Join Date: Apr 2006
Location: Manalapan, NJ 07726
Posts: 17
The 750 Source 4 PAR would do the job just fine. You would use the narrow or the medium lense. The source 4 PAR is brighter than the source 4 leko. You can't get the fine cut with the PAR, but it dosen't seam to be nessary for this shot. The Par is very small. Do you have a cardollini? You could use zip cord to power it, but I wouldn't leave it on all night.
I also think the light should come from the back. I think this was written about earlyer in this thread, but I wanted to re-empize it. It would glow the hair and any clothing the actor is whareing. Take that 500w and pull the bulb and put it on the lecturn or podiym to light the front of your actor. You will have to rig that carefully not to burn anything. A little blackwrap should help contorl the spill. Put every thing on Vareacks (dimmers). Hopefully the church has dimmable over heads that you can contorl.
My wife loves the show Touched by an Angle. I think they are at least useing a 5k if not a 10k for the Godlight. Most likely a 10k with some CTO.
Others have had very good smoking ideas, that you can ponder on.
__________________
To capture an image, any camera needs a certain amount of illumination for proper exposure.
Then start taking light away.
Charles Hohenshilt is offline   Reply With Quote
Old February 18th, 2007, 12:19 PM   #29
Wrangler
 
Join Date: Dec 2002
Location: Mays Landing, NJ
Posts: 11,542
Quote:
Originally Posted by Charles Hohenshilt
Put every thing on Vareacks (dimmers).
Actually you're thinking of Variacs. That's funny, I haven't heard anyone use that term in years. When I started doing stage lighting in the 1960's we thought these things were great, but you don't see a lot of them anymore. The name is a contraction from variable and AC. A quick Google search shows that they are actually still made - I did not know that! http://variac.com/staco_Variable_Transformer_Map.htm

Most dimmers you will find today use solid state devices which are much cheaper and smaller than the old Variacs. But Variac is just a brand name, that kind of dimmer is known as an autotransformer.

Sorry, I know this is all OT but your mention of Variacs brought back some old memories :-)
Boyd Ostroff is offline   Reply With Quote
Old February 18th, 2007, 05:10 PM   #30
Major Player
 
Join Date: Mar 2006
Location: Los Angeles
Posts: 439
I actually just tried to rent light kits with SCR type dimmers. I specified till I was blue in the face that I wanted small household-type scr dimmers, SMALL and cheap, max 600 watts. When I picked up the gear (at closing, of course), they had the light kits in HUGE pelican cases. I asked 3 times before leaving "this case is just the dimmers? Little squeezes, household? 600 watt max?" The guy reassured me... "yeah, the little guys with wooden boxes." And I asked again - "NOT variacs, right? Little household ones?" He seemed annoyed that I kept asking. Well, needless to say I got back to check through the kits, and sure enough I had a pelican case 100lbs full of Variacs! Great for the studio, not so great for setting up one-man band kits for airline carryon.

BUT, Variacs are fantastic and as of yet, no electronic dimmer can do the same thing. They dim extremely smoothly, and generally without any buzzing. When you dim a light and hear a "bzzzzzzz" it's the filament actually vibrating because of the fact that the dimmer itself is chopping the sine wave of power. Variacs literally change the voltage and do so without altering the frequency of power, so they dim smoothly and quietly. Also, because they are giant variable transformers, they can also boost the output voltage. So if you're on 110v wiring (not common) you can boost to 120 to get the proper voltage to your lights. Or, if you don't mind frying a lamp or 2, you can get that little extra brightness for a quick shot.

Ok, back to the topic at hand - if you're using the shaft effect, definitely put it on a variac, especially if its hung WAY up - you won't be able to scrim it, and that type of fixture is meant to be dimmed electrically/electonically anyways.
Jaron Berman is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > Photon Management

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 07:29 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network