Flash Light vs Continuous Light

Often young budding photographers ask me the question of what they should choose flash studio to begin without having to open a credit on the next 20 years.

But what equipment is needed? How much should we spend to be able to take photos in the studio and succeed?

I suggest you see in this first part the first choice. Dictfurniture will discuss here the choice between continuous light and flash light, the pros and cons.


My First Studio Homemade !!

Personally, when I was young, long ago;) I created my first site studio with three spots on which I mounted drives.

As broadcasters between models and the spots I had built frames with lintels on which I had stretched parchment paper.

As I wished that “broadcasters” are moving, to keep them up I planted feet in paint cans that I filled with sand.

As I was using reflectors survival blankets to gold and silver, white surface short all full of trick that allowed me to start and make my hand, without ruining me.

The problem of this material put out an astronomical electricity consumption and heat spots that gave off was the lack of precision in the control of light output. I could not afford to put anything on the spot without the risk of fire.

Basic reminders of your college physics course

The color temperature

First things first.

  • Continuous light with an incandescent light bulb produces a 2500 ° K color temperature.
  • Continuous light witha halogen bulb produces a 3400 ° K color temperature.
  • Aflash of lightning in a color 5600 ° K.

The Kelvin is an average of the spectrum covered by the light generated. More the number of degrees Kelvin and the greater light bluish and the Kelvin its bottom over the color of light reddish. Below 1000 ° K light generated is called infrared therefore invisible to the human eye. It produces more light, only heat. So for the same amount of energy lightning flash of a product less heat and more visible light than a halogen bulb and more than an incandescent bulb.

The sensors of our cameras are more sensitive to high-frequency light. The specter of a lightning flash is the closest white light (5400 ° K) among the three types of bulbs cited so far. Clearly this means that the flash is one that produces a light amount for the digital sensor receives sufficient amount of information to not see appear noise on blue with less energy and less heat.

Adjusting the light source

Unlike the flash produces the same color spectrum that can increase or decrease the power, incandescent and halogen lamps tend to emit a smaller spectrum, so more red. So with continuous light it is better to remove the source of light than lower power.

So the fineness of the continuous light adjustment is felt from the light to flash. By moving the light source model, the width of the light beam is wider therefore less accurate.

 Power adjustment Watt and Watt-second

The electric flash output is expressed in watt-second (ws), the power of continuous light is expressed in watts (w). What does that mean ?

The transformation of the electric power expressed in watts and watt-seconds into light energy is realized with a more or less energy loss. The difference between the flash and continuous light is the flash stores the energy in a battery and releases this energy in a very short period of time (between 1 / 500s and 1 / 5000s).

To demonstrate the equivalence light power emitted by a flash and continuous light, we must transform watt watt-second or vice versa. It’s pretty simple. Simply divide the flash output by the time of lightning or multiply this time by the power of the continuous light.

A simple example. Take a standard flash with lightning speed of 1/1000 sec .. A flash 1000ws liberate 1000w / 1000w is 1 during the flash. At the same time the continuous light 1000w 1000/1000 produce dry. 1w either. Basically for a flash of 1/1000 sec speed.continuous light to the photographing scene receives the same light with a flash, it is necessary that the continuous light is 1000 times more powerful than the flash. Basically with the continuous light at the beginning you have a model and end a grilled model). If the problem differently with for the equivalent of a flash with a flash 1000ws 1 / 1000s in continuous light you will need a 1000w power for 1s.

A small table showing you the energy to an equivalent result between a flash and continuous light:

Flash en ws continuous light (w) 1/50 sec. continuous light (w) 1/80 sec. continuous light (w) 1/100 sec. continuous light (w) 1/250 sec.
30 ws 1 500 2 400 3 000 7 500
500 ws 25 000 40 000 50 000 125 000
1000 ws 50 000 80 000 100 000 250 000
2000 ws 100 000 160 000 200 000 500 000

Why is it better to choose the flash continuous light?

The sensors of digital cameras collect the light intensity of a scene the time of installation. If we start from this principle and we accept the physical principles mentioned in the previous paragraph, we can conclude that to have the same light on a photo to a scene must either have a very important power light continues as the shown in the table above, another solution is to lengthen the exposure time.

For example if I have a flash of 100ws with a flash time of 1/500 sec flash. to have the same light on my picture I have used continuous light 500w with 1/100 sec exposure time.or continuous light 5 times more powerful than my flash and an exposure time of 5 times longer. So if one has continuous light less powerful it will be essential to place the camera on a tripod. It’s not practical and it is possible only if the model is stationary. Asking the model to stand still will tire more the model and the photographer and the photo shoot will be longer.

Once seen the problem arise. For a scene frozen like a still life it will not be a problem especially if we set the camera on a tripod. By cons, for a person who jumps for example, the exposure time is too long. It would take an exposure time of about 1/200 sec. to freeze the motion and thus doubling the power of my continuous light in my previous example is a continuous light 1000w with 1/200 sec exposure time.

The other possibility would be to increase the ISO, but in this case we must accept to deteriorate the quality of the photo. A last possibility is to open the diaphragm more of our goal, but in this case we reduce the depth of field. Besides most lenses have an optimum dive 2 or 3 f-stop of the maximum aperture.

Another disadvantage of the continuous light with respect to the flash heat. Heat for models which can irritate the make-up when models start to glow due to perspiration. But also the heat for accessories. Unlike flash accessories, accessories for continuous light must be fireproofed due to the heat. It also requires that the lights are broken boxes. Everything is more expensive.

Finally the flash consumes a lot less energy than continuous light, it is easier to transport in external flash with a battery. For continuous light have to be transported a generator, which is not possible everywhere because of the noise and pollution.

The disadvantages of flash

The disadvantages of flash, because it takes much, are:

  • The scene is not informed before it takes the picture.Unlike continuous light adjustment is less clear that we can not see the result of adjustment of the light that once we took the photo. To adjust the flash is used guides flash and light meter. The histogram can be used to adjust the flash if one has no light meter.
  • The flash is not suitable for video.It’s a little off topic, but we must take into account at a time SLR are all video and high quality.
  • If you want an extremely soft diffuse light, as in the photo-cons, the flash can be more difficult to master.The Harcourt Studio uses continuous lights. They do not direct the spots directly to the models. The spots are directed to reflectors which reflect diffuse light. But on the other hand they only take 10 photos in total during a session.

I use and that I recommend

Here are two kits that I have tested and are of the same brand that I use outdoor Elinchrom E20843 Accessory Camera Black

It is a fact kit

  • 2 D-Lite RX ONE who are professional quality flash.
  • 2 softbox de 66cm x 66cm
  • 1 carry bag
  • 1 sync cable
  • Its power is variable from 6 to 100 joules each.
  • The charging time is 1.5 sec.
  • the duration of the flash is 1 / 2200sec.
  • it contains a lamp driver 150w
  • A temperature of 5500k
  • an integrated radio transmitter Skyport RX
  • and the kit to a total weight of 9kg
  • This kit can be put on Elinchrom Battery

A kit with 2 flash: Elinchrom D-Lite Kit ELI20842 RX 4 2×400 joule Flash Light

This kit consists of as above, but instead of 2 D-Lite RX ONE torches,

  • il a 2 torches D-Lite RX 4
  • The power of each flash is 400 joules.
  • the duration of the flash is 1 / 1000sec.
  • This kit can be put on Elinchrom Battery

Otherwise the rest of the kit is identical to the previous

This kit is even more professional and highly scalable

  • flash compact portable 400 Ws.Power: 400J
  • A temperature of 5500k
  • Charging time (s): 2
  • flash duration (s), with 0.5 t torch RQ S / A: Exit A (100%): 1/1250 – 1/2800, output B (100%): 1/3000 – 1/5700, Output A + B (100%): 1/1500 – 1/4000
  • power adjustment amplitude (1/10 diaph) 6.6 diaph
  • Battery Li ion 280 lightning Charges in 1:30
  • a radio receiver Skyport
  • 1 Ranger Quadra RX Hybrid generator
  • 2 torch RQ A Hybrid (20134)
  • 2 bowl 13.5 cm (with protection)
  • 2 sync cables (2,5m)
  • 2 batteries Lithium-Ion
  • 1 Skyport Speed ​​Transmitter
  • 1 suitcase 1 charger
  • 1 sync cable (5m)
  • 1 shoulder

Finally the kit I use: Elinchrom E10287 Accessory Camera Black

This is a kit that I use for my outdoor photos. I double with 4 torches Ranger A.

  • Power (joules or Ws) 1100
  • Power distribution Asymmetrical
  • Skyport Radio plug with included adapter
  • 2m, ISO 100, refl. 48 °: 64 (100%), 45 (66%) or 32 (33%)
    power Amplitude (or 7 diaph) 100%: from 17 to 1100 66% of A: 11.5 to 733 33% B: 5 , 7-366
  • Recycling time (min / max) A fast 0.30 s / 2.9 s B: 0.19 s / 1.2 s
  • Recycling time (min / max) Slow A: 0.45 s / 5.5 s B: 0.22 s / 1.9 s
  • Flash Speed ​​(t0.5) Maximum Power – A torch (fast) 100% of A: 1/2300 s 33% B: 1/5120 s 100% A + B: 1/4310 s
  • Flash Speed ​​(t0.5) Maximum Power – S torch on 100% A: 1/1250 s 33% B: 1/2310 s 100% A + B: 1/2250 s
  • Number of flashes at minimum power (fast recycling time / slow) 5100/3700
  • Number of flashes at full power (fast recycling time / slow) 250/195
  • Power stability +/- 1 V
  • Lead battery (gel electrolyte) 12 V / 12 Ah
  • pilot lamp 2 x 50W / 12V or 1 x 100W / 12V
  • Battery charging time (loaded. standard) 5h
  • Battery charging time (loaded faster.) 3h
  • Dimensions (with battery) 19 x 14 x 28 cm
  • Weight (with battery) 8 kg
  • Comes with a battery, strap, a sync cable, charger.

Personally I am very happy and I train for almost 5 years without ever encountering a problem. 2 sets kits are quite heavy, but at a price; o)

In conclusion to go further

I concoct new items around the photo studio technique. In the next article we will discuss the broadcasters and the different accessories that are used in the studio and why is used more than any other accessory.