I had been using a 1k fresnel through full diffusion paper to light my subjects with but recently I've found that using 300-650 watts makes skin look my natural. What do you guys usually use to light for standard interview shots? Don't know if it matters but im shooting on a 60D.
What wattage do you guys usually use for medium to closeup shots?
- Thread starter dtjohns1
- Start date
What counts is the exposure you are looking for. For shallow depth of field to soften the background you need no more than F4.0 and better at F2.8. I light interviews with Kinos, so can't help with tungsten much but I used to use 500W or 650W in a softbox or through an open frame skinned with diffusion for interview keys.
Aaron De Pry
Active member
I use a 650 fresnel with a softbox and a 300 (sometimes 250) as a backlight. Sometimes I will bounce off a shiny board for a fill. It all depends on the location.
j1clark@ucsd.edu
Veteran
Since I've not shot with 'continuous' lights, coming from a still background and either using 'natural' light, or strobes, the use of 'Watt' to me is somewhat misleading. Different lights have different output in Lumens per Watt, and Lux/footcandle values have direct 'exposure' relationships...
So, for example I like to shoot my GH-1 with the 14-140 lens at 5.6. So, for 24 fps using a 1/60 shutter, and an ISO value of 100, that means I need 120 footcandles of light. (Or bump the ISO up to 400, I can shoot with 30 footcandles.)
The photometric specs for an ARRILITE 1K, gives a range of footcandles at 10 feet, ranging from 1300 to 100 or there abouts. On the other hand, from the Lowell pages for their 'tota' light, a 750 W light gives about 60 Fc, at 10 feet...
So, if I used the ARRI from the specs, I could get my 120 fc and use ISO 100, from the Lowells It looks like I might have to go to ISO 200 to get my desired exposure.
How do you know how many fc you need for a proper exposure? I'd like to know.
Is there some type of math formula or something? -- I've heard people talking about this before, but I got no idea where they are coming up with the fc numbers.
Paul Hudson
Vacuum Tube Member
Foot candles can be found on a good light meter.
j1clark@ucsd.edu
Veteran
As mentioned by Phudsontx, a 'good' lightmeter will read out in FC or LUX depending. However, when you are standing at the rental house counter, ordering your lights... you need to know what the light output is, so you can choose your lights accordingly... and pay for just what you need...
With that in mind, there are various tables on the net that will give the footcandles needed for a given F-stop/ISO/Shutterspeed.
One 'magic' incantation is ISO 100 f/2.8 @ 1/60 requires 120 Footcandles worth of light. (1/60 seems to be recommended for places where 60 Hz power is the standard... 1/50 for 50 Hz power lands (aka PAL lands...)).
Here is a URL for a table with more ISO values vs. f-stop, for a 24 fps with a shutter of 1/50.
http://www.scribd.com/doc/39000382/6/Table-7-2-F-Stop-vs-Foot-Candles-for-Various-Film-Speeds
The big caveat here is:
Every meter is 'slightly' different, the f-stop on the 'non-cine' lenses are not absolutely accurate, I've not tested shutterspeeds on digital cameras, but in the olden days shutter speeds for still cameras were notoriously off...
Hopefully digitial has improved that variable...
So, you still should test/meter but this sort of consideration will get you in the ballpark at least.
So using my incantation above:
If I want to shoot at F/5.6, that's 2 stops up from 2.8, I'd ahve to have 4x the light, or 480 FC falling on the subject. If I don't like that, then I'd up the ISO to 400, and get, back to 120 FC for a f/5.6 setting at 1/60, with the higher ISO value.
Correspondingly, if I know my camera doesn't have too much noise at ISO 400, I can shoot at 2.8, 1/60, with only 30 FC of light...
One of the reasons why you may want to keep a light 'low', is because spill will occur, and with the hotter light, you may have more light on the 'shadow' sides that you want for a 'dramatic' lighting
effect... so, by keeping it low, the 'bounced' light is more easily managed with black curtains, etc. and then when you do 'add' additional light to soften the shadows, you do it with more control...
Update:
The URL I gave above, appears to be the Harry C. Box book, "Set Lighting's Technician Handbook", so I don't know if it is up 'by permission" or not. So, here's another URL to a google books entry:
http://books.google.com/books?id=dyKZeoW3PFwC&pg=PA107&lpg=PA107&dq=footcandles+table+iso+fstop&source=bl&ots=eD6MnTFvJI&sig=8dnF7MQMMHHpsCeWXfQ5r1yUd40&hl=en&ei=28F3Tf67HZKisQOTwMC5BA&sa=X&oi=book_result&ct=result&resnum=8&ved=0CEgQ6AEwBw#v=onepage&q&f=false
For a similar table. This one is in terms of Lux values, so one needs to divide by 10.76 to get the Footcandle values.
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