Continuous cold light for LF?
First post here, so I'm nervous...
For half a year or so I am shooting 5x4. So far test shots and learning, I am mainly using it for portraits. With the end of summer in sight (I'm in the Netherlands), I am looking for more light. Most of my photography is daylight based and I am leaning towards continuous light.
I am wondering if someone can point me in the directions of power needed for - mainly - head shots.
I found the Calumet Quattro lights (they claim to be about 800W compared to traditional). From what I understood from "The Web", continuous light needs a lot more power than flashes. Any thoughts on these, or other recommendations?
The goal is to shoot ISO100 film at about f/16 with a reasonable shutter time.
Those clf fixtures are not going to get you where you want.
I shoot portraits with hmi's through various gobos - a 1.2k fresnel and a 1.2k par, sometimes supplemented by a couple of 200w jokers. HMI's are about 3-4 times as bright as tungsten fixtures (you'd need about 20 quattros to get similar output) At f16, depending on the amount of ambient light, I'm usually in the neighborhood of 1/15th at 200 asa. The quattro's you're interested in won't have the power or the punch to accomplish your goal. If the ambient exposure will give you f/16 with an exposure faster than a half second, the quattro's will most likely not even register.
If you're really intent on using continuous lights you'll get closer to your specs by using sunlight and reflectors.
Originally Posted by BZP
Flashlight are measured in Watts/sec , continuous lights are measured in Watts
Think of a figure for Watt/sec a flashlight delivers for useful lighting. Then multiply that number by the reciprocal of the nominal flash duration and you got the Watts of your flashlight. This would be roughly what you need as wattage from your continuous light. With incandescant continuous light you even would need about a magnitude more Watts.
Aside of that issue of very low electrical efficiency of incandescant light you do not need more power with continuous lights, rather the same as with your electronic flashlight. But the flashlight has an enormous outpout concentrated in a fraction of time (1/500 sec). The same huge output must be delivered by continous lighting all the time (or least the moment of taking, practically a second with appr. switches).
Such would be beyond the limits of practical lights.
Last edited by AgX; 08-19-2013 at 08:55 PM. Click to view previous post history.
I don't know if Sanders McNew is still around here, but he uses a bank of CFLs he built himself--something like 20 bulbs attached to a plywood board in a grid with no diffuser. He usually shoots 6x6cm or 5x7", with the light fairly close, but I don't know what his exposures are or what bulbs he is using. It works though (scroll a few pages in to his photostream for the nude portraits against a white background for the shots made with this lighting)--
frotog, AgX and David A. Goldfarb:
Thanks for clarifying. I was hoping to skip past "shooting in the dark" and am finding it hard to find some hands-on experience every now and then.
But I guess I'll better look for strobes and get used to it.
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If you're rich enough, go for professional HMI + fluorescent lamps. Otherwise you can still shoot using continuous lighting, but with some constrains.
- tungsten (halogen) bulbs are small (you can use them as a source of hard light), cheap (9000 lux for 15 Euro), but inefficient - not only that your electricity bill will be higher (which is perhaps negligible comparing to all other costs), but you must consider heat they emit, maybe air conditioning your studio; your soft-boxes may not survive, your snoot will start glowing red; they have, by definition, perfect CRI (colour rendition index), but most modern colour films are designed for daylight, filtering will take 1EV; they change colour temperature when reducing output; expect 2-4EV speed loose when using blue-sensitive or orthochromatic materials; with 1000-1500W in total you should be able to shoot the whole body, and you have a good chance that the body takes all cloths off because of heat; on the other hand I was able to shoot a model using only modelling lights (3 heads of 150W each) on ISO 400 film
- relatively cheap fluorescent light-bulbs; in the Netherlands you should be able to find a grow-shop, at least an on-line one; they sell utensils for home growing plants, especially one specific species; by chance some are also useful for photography, e.g. fluorescent light-bulbs up to 200W with cold daylight (6500K); as they are not designed for photography, no CRI or light stability is guaranteed; they pulse more than tungsten bulbs with 100 Hz frequency - shoot on 1/50s or better longer times; there are also studio sets available on eBay, but at price about 100 Euro a piece you can't expect any better quality
- fluorescent tubes - good for creating a soft-box replacement, perhaps you can buy something like this at a DIY market; remarks on cheap fluorescent bulbs apply
- professional fluorescent light sources - are expensive, but run the tubes on much higher frequency (or direct current), with stabilised current, and use much better (and expensive) tubes/light-bulbs
- LED sources are usually much overpriced comparing to fluorescent ones; energy efficiency is similar, CRI depends on LEDs quality (and price); advantages: ability to set any output without affecting light stability or white balance; almost unlimited life-time; no glass that can be broken; no mercury vapours inside
- street HMI light-bulbs are relatively cheap, small, require ballast; CRI good for black-and-white photography or special effects
It's good to ask film-makers, they have to use continuous lighting and need similar light quality as photographers.
If you are shooting B&W you can get a very natural effect by bouncing strong tungsten lights off a wall. Some years ago, I had a friend who wanted some large format portraits and I used 3 of the lights on tripods that you see on building sites bouncing of a wall and one pointing to the ceiling plus a large piece of polystyrene as a reflector. All were bought very cheap at a flea market and did the job well.
One other trick if going in close is to find a way for the model to keep still after you have focussed. I used to clamp a narrow piece of wood to the back of the chair so that they could keep the back of their head lightly resting against it - worked very well.
Best of luck with your LF photography.
If you really want to learn to light portraits begin with a bare 5 watt bulb. Yes, the subject must remain still, and the lens may need to be wide open, but that's OK. I make all portraits wide open. Move from there to a 100-150 watt bulb with a reflector (white mat board) for the shadows. Once you have mastered these you are well on your way.
[FONT=Comic Sans MS]Films NOT Dead - Just getting fixed![/FONT]
Thanks again for all the replies.
Perhaps I should have stated earlier that I have a strobe setup (strobist style) which is starting to show wear after using for some years.
I am looking into replacing these. One of the thoughts was to replace them with continuous light. Years ago, I bought some lamps at a construction store and fixed them with dimmers(I hope that's the proper English word), but heat and power drain made them not comfortable to work with (unless I will only shoot nudes, I guess).
I don't get into smartshops very often and plan to keep it that way.
When it comes down to a full blow HMI setup, I think I'd rather spend the money on a portable flash kit with enough power. That should keep things easier on location.
Thanks everybody for clearing my head.
Additional advantage of such design is that you can use it for garroting ugly models
Originally Posted by David Allen