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The issue with a moon lighting effect is that IF you want it to coming from a backlit angle, can you get it high enough for your widest shot?
So you have to calculate that — getting something to raise a light very high may be more of a budget issue than what light you are using, which is also dependent on what ISO and f-stop you want to shoot at. With some digital cameras, a single Skypanel 360 would light a block at night for moonlight, and that can be powered through a household circuit sometimes, but can you afford an 85′ condor for example?
Yes I could hire industrial condor. It will go up to 150′ hight. How much lamp should need for f 2.8 at 800 ISO. Not 3xacltly back light. It’s over head only. Need 200′ area illumination.
The easy answer is Day-4-Night, but I hate that as it nearly always looks rubbish. Even on big-budget productions, Day-4-Night nearly always sticks out like a sore thumb.
The trouble with pannels is that they are not sharp like moonlight. For that reason, I would use a single, powerful industrial light, even an LED and set the shutter speed to 25th of a second to avoid flicker. You can also bolt several building lights close together so that they are about 35cm across for a tight lighting source!
How much lamp power? Depends on the camera and the lens! You would be amazed at what you can get away with using modern cameras! Suck it and see is the answer!
There are photometric charts that you can study to find what light will give you the required foot candles and width of beam at any given distance. I would start by looking at the chart for an 18K HMI. To shoot at 2.8 and 800 ISO you need something like 12.5 foot candles depending on whether that is a back light or a front light.
Need Frontal light. But how do you calculate width of the area relative to width of the beam. Could you explain little bit.
What’s your opinion about 3xM40 par lamp Ganged through diffusion on over head hight.
I searched photometric chart on arri websites. Couldn’t find. Could any one most of the lamps photometric chart linked websites!
Hello Vanniyan,
Here is the photometric chart of the M40
I hope this can help.
I wish you a nice day.
Max.It seems I can’t able to post a reply with a link to a tool to calculate beam angle/distance.
I will retry soon.I would also share with you what I think is a powerful source and tool that helps to calculate beam angle/cover area/distance, height etc.:
Search on Google: Robin Barton beam angle calculator
Just for fun, I will try to do this calculation based on your situation, just to train my mind and also since I haven’t “DP” something in a long time (Lol but also sad😅).
As you probably already know, the photometric specs are without any diffusion in front of the lamp, and the light drop of your source will depend on how thick the diffusion is.
The same is applied, I think for the “spread”, a thick diffusion will spread the light more, basically changing the “beam” angle of your original source.Of course, like you, I will wait for an eventual answer from Mr. Deakins that are way more experienced and talented than me in this kind of situation so I can learn from his words.
As I said before I’m only trying to train myself and my brain for a tricky but interesting lighting situation like yours so don’t be severe with me 😁.If I can ask myself a question to Mr. Deakins or whoever knows the answer. If we have a lamp at a distance of 100′ but a height of 120′. At this point should we have to calculate the falloff based on the furthest point? I don’t think it’s possible that the fall is somehow “added” between the two distances.
Apologize for my bad English,
Max.Where did you get that photometric data. I need to read all kinds of lamps photometric data. Could any body give me pretty websites link
I could use Google and find the links… but then I’d wonder why you don’t use Google and find the links!
Master Roger I saw arri 18k photometric Data. It shows me at thirty feet it gives you 1495 foot candles(Full flood), 50 degree beam width. How do I calculate ISO. Is it All photometric data for ISO 100?
My most doubt is the beam width 50 degree at 30 feet. How to convert 50 degree beam width to width of the area(feet)
Vanniyan if you search on Google for these words: Robin Barton beam angle calculator, you can find a page with a calculator of two scenarios, and roughly you will have an idea of the area that the beam angle cover at a certain distance (and a height).
But, in my opinion, you have to consider the diffusion that you would to use because, in my opinion, could alter your final beam angle and so the whole area that you will cover with your light.
About the conversion FootCandle/Lux to exposure, Mr. Deakins tells you that if you want to expose an aperture of T2.8 at 800ISO 180° ShutterAngle you need something like 12.5FC. With this in mind, you can consider if the amount of FC/Lux that you will have in your action area is enough to expose what you want to expose (If you want to shoot at T2 for example you need the half of FC because you open your lens by a STOP but if you want to shoot your scene at T4 you need the double of 12.5FC).
As I said before, this is what I think should be, but there are masters and legends on this forum like Mr. Deakins and Mr. Mullen that can be more precise than me.
I hope this can help you.
I wish you a nice day,
Max.
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