Saturday, July 07, 2012
How an Umbrella Works
- LiteStand: large
- ADH 30” Silver Adjustable Umbrella
- ADW 30” White Adjustable Umbrella
- RUD 30” Shoot Through Umbrella
The umbrella is an economical lighting tool that is quick and easy to use. It is typically used for portraiture, although it can be used to light other subject matter as well.
Because of the price and the ease of use, many shooters, who need to set up and move a lot during a shoot, like the convenience of the umbrella. Many photographers who shoot in commercial kitchens for magazine spreads like to use umbrellas for these reasons, and also because umbrellas, as compared to soft boxes, take up much less room in the cramped quarters of the kitchen setting.
In this lesson, we'll look at the umbrella, how it works, and why it's used.
(Click on any thumbnail image below for an enlarged view.)
- Comparing a bounce umbrella to a shoot-through umbrella
- Comparing fabric efficiency with umbrellas
- Comparing contrast with umbrellas
There are several types and styles of umbrellas available on the market and the quality can vary widely.
For this lesson, we'll look at three models made by Photoflex:
- RUD - a "shoot-through" white/translucent umbrella
- ADW - an adjustable white umbrella
- ADH - an adjustable silver-lined umbrella
First, we mounted a strobe head* onto a LiteStand and attached an ADW (white) umbrella onto the strobe head. We positioned this setup approximately 45 degrees to the right of the set, and raised so that the light was pointing down at roughly a 45-degree angle. The umbrella ended up being about 48 inches away from the subject matter (figures 1 and 2).
*NOTE: In this lesson, we used an early prototype StarFlash 300 Watt/second strobe head. Any of the StarFlash strobes currently available will work just as these did.
When measuring the light output of a given light source, it's important to know where to take the measurement. The amount of light falling onto your subject is what you're trying to measure, not the light emanating from the light source. As such, you should take your measurement where your subject matter is. (figure 3)
With the light in place and powered up halfway, we used the light meter to establish the starting point for exposure settings:
Shutter Speed: sync speed of 1/200th of a second
With the camera dialed in, we took our first shots. In the results, you can see the effects the ADW had on the subject (figures 4 and 5).
Here, we see soft, broad highlights on the subject. Still, the contrast level here is significantly greater than what you would get with a soft box. We see detail and color in the highlights but there's not a whole lot of detail in the shadows.
The goal of the next step was to help control our contrast and try to open up the shadows.
To do this we removed the ADW umbrella and installed a RUD umbrella. The RUD is a shoot-through umbrella, so we will need to re-set the light by moving it out from the set and spinning it around.
Once we had installed the RUD, we set the light on the same line and height as our first shot and set the distance to 30 inches from the umbrella to the subject (figures 6, 7, and 8).
Because we made changes to the lighting, we needed to take another reading to check exposure (1/60 @ f/11). We gained one stop of exposure because we were transmitting the light, not bouncing it, and the light was closer to the subject. Once we had reset the camera, we shot the next set of images (figures 9 and 10).
In figures 11 and 12, we can compare our results so far. We see in figure 12 how the RUD has reduced the contrast and opened up the detail in the shadows without sacrificing the look of the highlights. Again, this is an illustration of how diffusion is the friend of contrast reduction.
The next step was to increase the contrast of the shot by adding the ADH (silver) umbrella. Silver reflective surfaces will result in higher contrast light output than white reflective surfaces.
To accomplish this, we removed the RUD umbrella and reset the light into the original position from our first shot. Once we had the light reset in position, we installed the ADH umbrella, and set the light back to 48 inches from the subject (figures 13, 14, and 15).
Again, since we have made changes to the lighting we took another meter reading to check the exposure levels (1/60 @ f/16). We are back where we started so we reset the camera and took some shots (figures 16 and 17).
In our results, we see the increased contrast produced by the ADH umbrella. Our highlights have a harder edge to them and detail has been lost in the shadows, they are blocked up with little or no detail at all.
In figures 18 and 19, we compare the RUD umbrella (shoot thru) with the ADH umbrella (bounce silver). These examples show the “soft” vs. “hard” effect. In figure 18, the diffusion has softened all the aspects of the shot and in figure 19, the hard silver surface of the ADH has increased the contrast and the overall look of the image.
In figure 20, we show a comparison of each of our results side by side so you can see the effects of each.
This lesson has explained how umbrellas work and shown the type of light certain styles of umbrellas produce.
Umbrellas can be an effective and economical solution for your lighting needs.