light bulbs etc.
Posted 05 July 2005 - 03:10 PM
1.considering how much material is shot in one day, and considering the time that is spent in preparation of a set, how often do tungsten bulbs get changed on movie sets?
2.And one more question, how do you live and breathe on small sets (in case of tungsten lighting), isn't it hot?
3.What is the avarage wattage of key light beam for a room sized set these days (I assume less than before due to more use of fast film)
4. Do you people in cinematography ever "cheat" by putting stronger bulbs in practicals (like 500W bedside "night" lamps)
5. Has the above ever been done on street lamps (for example putting 4K's in street lamps etc.)
I can't imagine burning my photo floods for so long, the bulb lasts for max 75 hours, and I would melt away
Posted 05 July 2005 - 03:47 PM
When they go out.
> 2.And one more question, how do you live and breathe on small sets (in case of tungsten lighting), isn't it hot?
> 3.What is the avarage wattage of key light beam for a room sized set these days (I assume less than before due to more use of fast film)
There's no rule-of-thumb for this. It all depends on the look you what, the f-stop you're shooting, what needs to be illuminated and what doesn't, etc etc etc.
> 4.Do you people in cinematography ever "cheat" by putting stronger bulbs in practicals (like 500W bedside "night" lamps)
I don't. I don't like fires.
> 5.Has the above ever been done on street lamps (for example putting 4K's in street lamps etc.)
Not that I'm aware of. The electrical co-op doesn't like fires either.
Posted 05 July 2005 - 03:54 PM
I have used stronger (250w 3,200k) than usual bulbs in practicals on a set before, it was actually a bedside lamp in a dingy motel. I also heard that on 'Constantine' they replaced all the bulbs in the street lamps of an entire stretch of road with tungsten blanced 5k bulbs, I don't know if it's true thats just what I heard.
Posted 05 July 2005 - 04:24 PM
Photo flood usually are glass bulb. Tungsten-Halogen are quartz-iodure lamps. They allow a use of averagly 150 hours. Also they don't get as hot as glass bulb photo flood do.
The smallest the set is, the less light it needs, so it doesn't necessarly get very much hotter than a large one
It's known as a common rule that you need 500 w per meter square as to get a f stop of 4 at 100 ISO. It's very empiric but if you work at 400 ISo, you then only need about 125 W per meter square, that means a set of 200 meter square requires about 2500 W to get that aperture... purely ampiric, but can give you a base.
We practicaly don't cheat anymore with over power lamps since sensitivity allows to work with practicals without cheating... unless they are not too weak...
In the street, it's not easy to have the proper bulbs, change them etc.. usually we work with the street natural lamp and add light. We can also simulate a street light with our own material (a 2kw open face blondie can do the job of simulating a street practical, a space light can give a good KL in a street...)
Posted 05 July 2005 - 06:41 PM
The "photo floods" I use are tungsten halogen, not basic glass bulbs
those are my beloved babies
anyway, regarding the simulation of street lights..
how do you do that, do you hang the lights somewhere high on location?
Edited by Filip Plesha, 05 July 2005 - 06:42 PM.
Posted 05 July 2005 - 07:19 PM
Posted 05 July 2005 - 07:31 PM
"photofloods" are a special kind of hosehold bulbs that give more light and are cooler in color temp.
I didn't mean photofloods as in that, I ment photo floodlights, as in floodlights (lights wihtout a lens) that are used for photography. These are U shaped halogens, and not photofloods
sorry about that
Edited by Filip Plesha, 05 July 2005 - 07:31 PM.
Posted 05 July 2005 - 07:40 PM
But I'm just thinking, since they are TH lamps, why do they get so hot and why don't they last longer ? I guess the 2 can actually be linked... May be due to the cooling system...
You may get the same lighting results with small Fresnel lamps or open faces, that wouldn't be too expensive to buy, would last longer and not get so hot...
I guess you don't use them "direct" anyway do you ? I mean you reflect them or use them through a diffuser I guess, so the little technology difference may not be a pain... Using Fresnel lamps could be a nice thing as well. I love Dedolights when it comes to small sources for use in still photography.
Edited by laurent.a, 05 July 2005 - 07:41 PM.
Posted 05 July 2005 - 08:05 PM
The ones I've been using since are 75h, but 3200K. It seems the hotter they are, the shorter they last.
The longevity of the bulbs has nothing to do with cooling because the hours are specified in the bulb specs regardless of the unit they are used in.
Anyway, regarding the heat, the light itself is not all that hot, it's just that I tend to move alot, setting this, setting that, and I sweat a lot because of that. And the lights aren't helping either.
You mention open face lights, aren't thos the same thing like these that I use?
I mean its a bulb, reflective surface and a protection (no lens)
..oh, yea, and sometimes I do use them direct, even for portraits, because I'm not really a fan of the stereotype umbrela flat soft look.
Posted 05 July 2005 - 08:15 PM
Funny your lamps were given for only 15 hours !
Posted 05 July 2005 - 08:25 PM
The only purpuse of it is protection (in case it blows up or something) , and it can be used as a glass filter (comes in different colors, or can be a diffuser)
But it's not sealed. There is open space around the glass where air is blowing from the rear, so I think it has same amount of ventilation as an open face with a grid has.