Tuesday, July 03, 2012
Portrait Lighting with Constellation3 Continuous Light Kits
Simple continuous lighting can produce beautiful results for many types of portraiture. But simply having good lighting tools can only get you so far. Knowing how to position them and set up lighting ratios will give your results that professional touch.
This lesson explores the use of a single main light with a reflector for a fill light and main light with a second soft box as the fill light. In both lighting versions, continuous lights are used rather than flash or strobe lighting.
(Click on any thumbnail image below for an enlarged view.)
- The Set-up
- Main Light with a Reflector
- Main Light with a Second Fill Light
- Tungsten vs. Fluorescent Continuous Lights
- Main Light Positioning on the Subject
- Fill Light Positioning on the Subject
Figure 1 shows a top view of the lighting set-up with the large soft box main light on the right and the white fabric 39"x72" reflector panel fill on the left. The Photoflex large SilverDome nxt soft box has the Constellation3 Starlite Tungsten lights installed. The vents on the soft box have been opened to allow for the heat from the Tungsten lamps to be vented out of the soft box.
There are four basic ways to set the White Balance for most professional and "pro-sumer" digital SLR cameras. Your can use AWB (Auto White Balance), the Tungsten setting, Kelvin color selection (you select the specific color temperature, i.e. 3200K for Tungsten), and Custom White Balance. In many cases AWB works well, but it can be affected by the color of the model's clothing and the background color.
The most accurate approach is to do a Custom White Balance, where you shoot a blank white card or piece of paper under the lighting you are using and choose it as the file to use for the in-camera Custom White Balance. [figure 2] It's important that the white card completely fills the viewfinder to prevent other elements within the frame from affecting the color balance.
Main Light Working Distance
The main light determines the direction and quality of light that falls on your subject's face and body. This light determines how flattering or unflattering the light will portray your subject. Here, we used a large soft box. Remember that the distance the soft box is from the subject will affect the quality of light on the subject. The general rule with a soft box is that the closer it is to the subject, the softer the light will appear.
Another factor when using continuous light concerns the quantity of light that will be produced for the exposure. When you double the distance the light is from the subject, the amount of light loss will not be two times, but four times the amount of the original positioning. With Tungsten continuous lights, heat is another issue. The subject will feel the heat from the light if it is too close. A good working distance for a medium or large soft box with continuous lights is 36" to 48", depending on the size and conditions of the room. This working distance allows movement of the main light in a semi-circular manner around the subject to modify the light pattern on the subject's face.
Setting the Subject to Background Distance
If you do not use a background light, the distance from the main light and the subject to the background is important. Basically, the background will be lit by any spill from the main light.
It is best to choose a working distance where the main light does not cast a visible shadow right behind the subject, but there is still enough light hitting the background so that it is not too dark. A subject distance of 36" to 48" from the background usually works best when using a medium or large soft box.
Setting the Exposure
Using a handheld exposure meter can help you dial in precise exposure settings quickly. To measure the exposure from a continuous light source, it is important to place your exposure meter (using the incident mode) where your subject's face will be.
With an exposure meter, you are measuring the light falling on the subject rather than the light reflected off of the subject. Make sure you do not block the path of light illuminating your subject with your body.
When working with continuous lighting and live subjects, it is important to use a shutter speed that is fast enough to freeze any minor movements by the subject, as well as to avoid any camera movement. (This is why it is also beneficial to use a sturdy tripod).
This Tungsten light reading with an ISO rating of 400 was 1/60th of a second at f/8.4. This is the same exposure as 1/125th of a second at f/5.6.4, which we used to shoot this series of portraits using the Tungsten main light and reflector fill. Remember, using a faster shutter speed will help cut down on motion blur, and a wider aperture setting will shorten your depth of field.
To learn more about depth of field, check out the following lesson on Web Photo School: Controlling Depth of Field
Setting the Main Light Height and Position
Once the main light distance and exposure are determined, the next step is to determine the height and position of the main light. One of the more flattering lighting patterns on a subject's face is what is known as a 2/3 view using short lighting.
With short lighting you are shooting into the shadow side off the face. Notice that the subject's face is also turned toward the main light, which is why it is called a 2/3 view. Figure 4 below shows classic 2/3 view short lighting. Also note the position of the nose shadow. The main light is placed slightly above the subject's head producing a catch light in the eyes at the 2 o'clock position of a clock. [figure 5]
The Reflector - Position and Fabric Choices
A reflector can be used to add a fill light to the shadow side of the subject. Since the fill is generated by reflecting the light from the main light source, the angle and the distance of the reflector will determine the quality and the quantity of light hitting the shadow side of the subject's face.
The fill light can also be modified by the fabric material used on the reflector.
In this example, a white 39"x72" fabric reflector is used to act as the fill light on the shadow side of the subject. The main light large soft box is angled to produce short lighting on the subject, while also hitting the reflector to add fill light.
Watching how moving the main and fill lights will change the shape of the subject's face is a visual practice that the photographer must execute with every subject. The beauty of using continuous lights is that what you see on the set is what you'll get in the camera.
The white fabric is soft and neutral when it is used as a fill light. [figure 7]
Notice the increase in the quantity of the fill light and contrast using the silver reflector. [figure 10] The distance and position of the reflector is the same as with the white fabric, but the appearance of the fill light has changed. As opposed to being soft, as it is with the white fill, the silver adds more contrast, similar to a hard light.
The gold reflector, when used as a fill light, produces a warmer look. Similar to the silver reflector, it is stronger than the white reflector at the same distance and angle to the subject. [figure 12]
Here's a side-by-side comparison of the three different fill fabrics we used. [figure 13]
Adding a Second Soft Box as a Fill Light
For the next part of the lesson, we replaced the reflector with a second large soft box as the fill light. When adding a second light, your overall exposure will increase, and so it helps to measure the fill light with a light meter.
Ideally, the fill light should be powered 1-2 stops lower than the main light so that the subject will have a three-dimensional look in the photograph. This is where a photographer must make a decision on the lighting ratio that best fits the subject. Again, with continuous lights you can visually see the adjustment of the amount of fill light, since what you see is what you get.
This is a top view of the lighting set-up with the new soft box fill light on the left and the main light still on the right. [figure 14]
From this wide point of view of the camera, you can see the height of both large soft boxes in relation to the subject. Notice the main light on the right is higher than the fill light on the left. The lower position of the fill allows light to fill under the subject's chin.
Here the fill light is measured with the main light turned off. The reading is f/8.2 at 1/15th of a second at ISO 400. You can see that the fill light on the subject's face is darker than the main light will produce.
This shows the effect of just the main light, with the fill light turned off. The reading is f/8.4 at 1/60th of a second at ISO 400.
Here is the main light plus the fill light combined. The reading is f/8.7 at 1/60th of a second at ISO 400. Again to achieve a faster shutter speed, we can reduce the f-stop by one stop and increase the shutter speed by one stop. This will give us f/5.6.7 at 1/125th of a second at ISO 400.
Here's a side-by-side comparison of the main and fill lights used. [figure 19]
The increase in overall exposure turned out to be about 1/3 of an f-stop. Keep in mind this will change if you move the fill light closer or farther away. The difference between the main light exposure and the fill light exposure here was about 2 stops.
The image below shows a wider final result of our model in a different outfit that combines the same main and fill light.
Changing from Tungsten to Fluorescent Continuous Lighting
The lighting principles already covered are the same when you switch from Starlite lamps (Tungsten) to CoolStar lamps (daylight-balanced fluorescent). Note that you'll need to redo the White Balance, since the CoolStar 150w CFL lamps are color-balanced for 5600 degrees Kelvin, as opposed to 3200K for the Starlite lamp. A new exposure reading will also be necessary since the CFLs (CoolStar lamps) put out about 1-1/3 less light than the Starlite Tungsten lamps.
Changing the Starlite Tungsten bulbs to the CoolStar bulbs only takes a few minutes, but it's important to let the Tungsten bulbs cool prior to handling them if they've been in use.
For optimal light output with the CoolStar lamps, you can replace the interior baffle within the soft box. The front face will still diffuse the light from the lamps, but without the baffle you'll gain a half stop or so.
Again, when changing light sources, you'll need to redo the Custom White Balance.
Figure 24 shows the reading of the light falling on the subject using the incident mode on the light meter. The reading is f/5.6.5 at 1/60th of a second at ISO 400. This is the equivalent of a 1-1/4 f-stop difference between the Starlite and the CoolStar lamps.
The result from the fluorescent lighting is essentially the same as the Tungsten lighting once the White Balance is set properly and the exposure is adjusted. [figure 25]
Tungsten vs. Fluorescent-Pros and Cons
The main differences between Tungsten and fluorescent continuous light sources are heat output and the amount of light produced. The Tungsten lights (Starlite) produce more heat and may not be best if you are shooting in a small, confined area. However, the Tungsten lights produce more light than the fluorescent lights (CoolStar). The quality of the light through the same soft boxes, however, is equal.
Simple Lighting = Classic Portraits
As you can see from the lesson, it is easy to achieve beautiful portraits with simple lighting. One of the advantages of using continuous lighting is the "what you see is what you get" factor, with no flashes popping to bother your subject. From the basic lighting structure illustrated in this lesson, it is easy to adjust the lighting to modify the look to fit your subject.
Remember to experiment and have fun!