Cinematography Mailing List - CML

Sharpest Lighting Source

Not too long ago there was a thread on solving a lighting problem with a very sharp source to create hard shadows. This got me thinking (Uh-oh) about different sources. We are all very familiar with controlling light and especially how to make a light softer by making the source larger or closer, etc. But what about hard, sharp sources? Of course, given it's distance from the subject, the sun is the sharpest. But what about light sources used in our business...which is considered the sharpest, hardest light source at a given distance from the subject.

I always think of condensor lamps as being the hardest. The follow spots, Dedo lights, foco spots... can all create pretty hard shadows.

One problem that comes up every so often is to get the effect of rain shadow on the wall from a window. This would need a hard source but I've never been that happy trying to get this effect. I recall Conrad Hall discussing the effect in "In Cold Blood" and after trying many sources he claims that someone panned a light across the set and he happened to see it create the effect accidentally.

I curious as to what opinions other people may have on this subject, especially for bright sources. I always see really hard, secondary light spilling out of the back of a fixture but it's never bright enough to film. Can you imagine turning the 10K backwards and upside down? Any other experiences or ideas?

Jim Sofranko NY/DP

For my money nothing beats a Brute arc lamp for hard sharp beautiful light. No double shadows, no flicker, just incandescent beauty.

- Ed Colman -

SuperDailies Cinematographer Supervised Dailies


Thanks for the refreshing question. I think working with hard sources makes you think harder- and its more fun, and I like the vivid look.

It seems to me that glancing light off a mirror always looks harder than the source itself- whether this is because of the rays bending, (like how 60mph feels like 99 when you take the exit ramp) or the glass re-focusing the beam, I donno.

I dont even know if I'm right, it may just be perceptual, but if so, I hope the film percieves it the way I do...

Caleb "just changed my brake pads, now *thats* hard" Crosby

Hi Guys :

Caleb's right. The best hard edge for the budget is a large diameter source bounced off a 4x4 mirror. The narrower the beam from the mirror, the sharper the source.

I've been on several sets where we used a 4K xenon and a mirror to punch hard-edged "daylight" through various windows of a set on a sound-stage. The benefit is that you can get that hard quality of light where it would otherwise be impossible, such as when there is only 6-8 feet between the set window and the wall of the soundstage. Also, you can keep the xenon far enough away from the set/mirror that it won't cause head-aches for sound.

On several occasions, I've rigged mirrors on different sides of the same set. When appropriate, it makes for quick turnarounds, as you simply pan the xenon from one mirror to the next and adjust the angle for the proper time of day, etc.

Sean Peacock - Gaffer Studio City, CA

It's because you are effectively getting your source further away from the subject, thereby reducing it's relative size... thus sharper shadows.

Sharp shadows & soft light are functions of size-of-source (and distance) relative to the subject.

Unfortunately, almost everything that makes a sharper shadow also reduces your footcandle count :

Panning off and using edge of fresnel coverage -- flooding a fresnel -- opening fresnel and using bare bottle -- and removing reflector too -- moving light further away (or mirror which does same) -- using a smaller fixture (or more compact bottle design like source-4's)

One of the only things non-source related would be to _decrease_ the distance between the subject and the wall onto which you are casting a sharp shadow. the closer the rainy window is to the wall, the sharper the shadows.

Anybody ever used a Big-Eye 10K as a soft light without benefit of diffusion frames ? Just put it 2 feet away from your subject and watch it wilt.

Mark Doering-Powell


I second Ed's response. I once had a series of spots to shoot in Mexico. They all involved live action, rear screen shadows and covered a large area. The best solution for a bright point source was a brute with the lens removed. Some problems -- The flickering flame above the arc can throw additional off color shadows even if the arc is in trim. There is a light baffle which can control the light from the flame, but I found that most of them were burnt away. The shop replaced the piece. They also cut a flat doughnut shape out of sheet metal which held back the light bouncing around in the housing.

The largest screen we created was about 12 feet by 30 feet. I remember shooting '98 (at 400 asa). The screen was at least 2 1/2 over reflected. Unfortunately, I can't remember lens stop, but I know we had to go to primes. I asked for the lightest screen material available. The sets were all raised so that we could keep the lamp on the floor and hide the hot spot.

I don't really understand the safety issues. We were careful to keep people away from the lamp and we flagged the light to prevent them from burning up their retinas. Is there a UV issue?

Good luck

Fortunato Procopio NY/DP

The solution we ended up applying was to drill out the reflector and back of an old Mole 5K. Due to the physical constraints of the set we ended up removing the lens and putting in a single for safety. My problem here was that the light needed to be pointed straight down.

The 4K Goya with the black reflector works well. 5K with no lens? Skypan? I think the problem we all run into with this type of light is that we get stuck needing something that can't be as far away as we would like. Either for exposure or placement reasons.

Is there a 10K Goya? That might do the trick in a 3200 situation.

David Perrault

This is exactly right. It is source size that counts. When you pull the lens off a fresnel you reduce the effective source size from the diameter of the lens down to the size of the filament pattern.

Another function of the mirror is to narrow the beam somewhat by cropping off extraneous flare rays from the originating source, reducing the effective source size some more.

Perhaps the sharpest source we can come up with (that produces substantial footcandles) is an HMI fresnel with clear glass instead of the lens.

BTW, Jim, the sun isn't the sharpest source. Set up a bare single ended quartz lamp of 600w or so (even better, a 250w GCA.) You won't get a lot of footcandles, but you'll get much sharper shadows.

Wade Ramsey, DP

I always use either a Desisti "Goya" or an Arri "X"

Whilst not as hard as a clear glass brute they're a lot easier to get hold of and use.

Goya comes in 2K & 4K the "X" also comes in a 6K.

The "X" is essentially a copy of the Goya and because it came later it has a few handling improvements, it's much easier to switch from the black hard source reflector to a silver flood reflector for one, both of these lights are great wide floods when used with a silver reflector, but they're not a hard source then.




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