Lighting predictions

[CharlesPapert]

One factor that needs to be considered in the discussion of how much output is required to balance against daylight is how big of an area you need to cover, as that will dictate how close your lights need to be. Also, what is the quality of the light you are looking to emulate. Hard light (sun) is easier because you can use a raw unit, whereas ambient daylight requires a soft source which of course is less efficient.

Just as an example of what it takes to combat daylight for a sizeable day interior, please see the following:









For each side of coverage, we created a wall of soft light that started from the windows just off camera and wrapped around to the front. It was a combination of bounce and pushing through diffusion. I can't remember the exact configuration but I believe it took two M40's and an M18 (so, close to 10K watts) to make up the wall, plus a few extra M18's to lift the backgrounds as needed. Even with that amount of firepower, the exterior on the girl's side was at least a stop hotter than I would have liked. The other side was backlit greenery, which fell in nicely. I had intended to soften out the highlights on the hot concrete in post, but unfortunately I didn't get to attend the color sessions for this show.

So we started with the wide shots and then went into tighter coverage, and with this scheme I didn't have to do any relighting. Now if we had only shot the closeups, I could have gotten away with smaller units, closer to talent...sort of. There's enough depth there that to keep things consistent, I would have had to push in a few rakes of heat to help balance things, but it wouldn't have looked as natural.

 

[CharlesPapert]

Just checked with my gaffer--turns out I was underestimating by a long shot on the instruments in use on that (it was last spring, many shoot days have elapsed since so not terribly surprising). Apparently on the setup towards the guy, we had an Arrimax 18K AND a 12K outside pushing through 12x12's of full grid through the windows, with an additional M40 through the upstage windows to light the background, plus another M40 bounce over camera and a Joleko bounce filling in the space between those. Slightly smaller on the turnaround, the 12K was replaced with an M40. Phil, it would be fair to call that "galactically huge" if you so desire.

The point being, it takes big guns to light a significant size space so that it can compete with bright sun.

 

[morgan_moore]

A quick note.

I just bought a couple of lupo 200s.

From my previous led tests it seems that the colour is OK, as fixtures they seem light and pleasant.

They seem like a good thing for a solo operator on a corporate shoot, as so much tidier cooler whatever than redheads and light to carry and no ballast and smart (like wearing a tie smart).

They have some punch.. but they are not going to be replacing rental HMI options.

S

 

[morgan_moore]

Here is the lupo, vs a card pointed at a grey cloudy sky.

with the WFM I did a shift in post to seperate the channels

Of note is the nice alignment of the green channel.

 

[egproductions]

One factor that needs to be considered in the discussion of how much output is required to balance against daylight is how big of an area you need to cover, as that will dictate how close your lights need to be. Also, what is the quality of the light you are looking to emulate. Hard light (sun) is easier because you can use a raw unit, whereas ambient daylight requires a soft source which of course is less efficient.

Just as an example of what it takes to combat daylight for a sizeable day interior, please see the following:

Hey Charles, thanks for sharing these frame grabs. I totally agree, the bigger the space and wider the shot needed, the more power you need in order to balance natural daylight, naturally. By naturally I mean diffused lighting that doesn't have a very fast fall off from the subject. To do this you have to keep the light source exponentially further away from the subject which, in turn, requires the light source to get exponentially larger in order to have something that is diffused.

I often shoot still photography for events in large halls. Granted, I'm not typically fighting sunlight but in order to fill the space with diffused light, I bounce powerful strobes in the corners of the room. I did the math one time and between all my strobes (4) the amount of power needed was something like the equivalent of about 1 million watts of tungsten. It sounds like a lot (and it is) but lighting requirments are all about the inverse square law.

 

[DLD]

I think it's square root if it's on the same plane.

 

[kohl-sudduth]

Just a quick note of gratitude for sharing all of your practical, direct experience Mr Charles Papert. Very valuable and learning a lot.

 

[ozmorphasis]

Just a quick note of gratitude for sharing all of your practical, direct experience Mr Charles Papert. Very valuable and learning a lot.

+1

 

[morgan_moore]

Just to throw in a wild one charles..

That big scene. I wonder what would have happened if you had just filled from the right without supplementing the light coming in.

Obviously this could have played havoc as the ext light changed through the day..

S

 

[CharlesPapert]

Sam, I'm guessing you are referring to the guy's side of coverage, with the windows on the left?

it would have been great to have a reference still of the existing levels at our shooting stop before we started lighting, I would estimate that the faces were roughly the same ratio but underexposed relative to that still by at least 3 stops. If we had filled from the right, it would have looked false as the logical source was the windows visible on left of frame, plus presumably some amount of ambience from ceiling lighting. Opening up to properly expose the faces with the ambient light levels would have resulted in the windows blowing out.