In this video we learn how to control the diffused and specular highlights in photography.
Tags:Diffused and Specular Highlights,contrast in photography,difused highlights,lighting education in photography,lighting in photography,photography tips,software cinema,specular highlights
Grab video code:
Male: Another factor of contrast control is between the diffused value and the specular highlight. For this example, the diffused will be the objective and the specular highlight will be the subjective. In this segment, we will keep the exposure of the diffused consistent and vary the intensity of the specular highlight relative to the diffused.
The nature controls of this factor are the size of the source of illumination, the distance of the source to the object, the surface sufficiency of the object and the tonal efficiency of the object. The first factor for controlling contrast between the diffused and specular is the size of the light source. Using our table top set up with the fishing tools still straight the effect of the size of the source.
Tim Mantoani directs the full photo scroll with the light reflector behind the table top set up with the scroll aimed to illuminate the lures. An incident meter reading is taking to establish appropriate exposure for the subject area. Using a single stove is the only source of illumination Mantoani records the image.
In this first image, the small light source produces a small very intense specular highlight both on the lures and on the glass surface because the two tones of both the lures and the glass are darker tones, the contrast where difference in brightness between the diffused value and specular highlight is great. With the addition of the large Chimera light back on the front of the strobe, the size of the light source has increased greatly. With the strobe still at the same distance from the subject area, an incident meter reading is taken once again to ensure a proper exposure. Mantoani then records the single image of the setup.
In our first image, the small light source produced the small intense specular highlight on the lures and the glass. The small size of the source focuses the light energy from the strobe onto a very small very small area which results in high contrast between the diffused value or true tone of the objects and the specular highlights. By increasing the size of the source with the addition of the light back, the size of the specular highlight is also increased.
The same amount of light energy is now dispersed over a large area on the lures and the glass resulting in a less intense specular highlight. If the specular highlight covers four times the size of the original highlight, it will return only one quarter of the original light intensity and although the amount of overall lights striking this subject area decreased slightly due to the use of the light back relative to the diffused value, the specular highlight has decreased in intensity. The result is a decreased in contrast between the diffused and specular.
Tim Mantoani: One of the biggest problems I see people are struggling with when they get into photography is controlling the specular highlight and the density of it. The first thing your eyes is going to go to in any photograph is the brightest thing and if it’s a wine glass and has this huge bright specular highlight on the side, your eyes is going to that and it’s not looking at the product plus you can't see through that highlight to see what the product is. So, if you're shooting electronics, you're shooting cars, you're shooting food or wine this is an incredible way to shrink down the contrast range in order to make these pictures better as far as reproduction but also prettier.
Male: Another contrast control is the distance from the light source to the subject. As the light source is move closer to the subject area, the intensity of the light increases and the relative size of the source increases resulting in an even larger specular highlight. Another meter reading is taken to ensure a proper diffused value in the subject area. Mantoani adjust the aperture to match the incident meter reading and records to do image of the lures.
Now, look at our second image reveals relatively high contrast between the diffused and specular. The large light bank set at a distance of approximately four feet from the subject area still produces or rather small intense specular highlight relative to diffused value of the lures and glass.
By moving the light source closer to the subject area, the specular highlight increases in size dramatically. It appears to diminish in intensity thereby reducing the contrast between the diffused and specular. What truly happens is that when the light source is move closer, the diffused value gets brighter due to the added light value for moving the source closer and the intensity of the specular highlight remains constant.
When a light source is moved, the diffused value of an object will increase or decrease in intensity by the square of the distance move. In this case, the source was moved from four feet to one foot from the lures four times closer. So, the intensity of the diffused value is 16 times greater. When a new meter rating is taken, the exposure is reduced for a proper diffused value and relative to the diffused, the specular highlight is reduced in brightness. The result is a decrease in contrast between the diffused and specular highlight. The key to this control is to keep the diffused value constant.
Tim Mantoani: One of the extreme examples of dealing with specular highlight is what we call specular compression. For instance, if you're lighting a drinking glass or a wine glass or a wine bottle, you’ve got to compress that very bright highlight the reflection of your light source down within the range of maybe five to six F-stops with the digital video camera. And specular compression has to do with the physical size of your diffused source and approximately where you're placing that source.
And if you can work these techniques into your work, it solves us enormous problems especially for people that are shooting in low video cameras. It can solve within a couple of minutes for some very simple tools and a very simple approach and it gives a beautiful elegant look on the camera.
Male: The third control of contrast between the diffused and specular is surface efficiency. We saw earlier how surface efficiency can affect the specular edge transfer. In the control of contrast, the surface efficiency affects the percentage of light return from the object. Smooth and shiny surfaces return a higher percentage of life than do matte of texture surfaces.
Therefore, the surface efficiency of an object is directly related to the intensity of the specular highlight return which affects the contrast between the diffused and specular. A textured surface does not affect the intensity of the diffused value but it will reduce the intensity of the specular highlight thereby decreasing the contrast between the diffused and specular.
The final control of contrast between the diffused and the specular is tonal efficiency. The tonal efficiency affects the percentage of light return from the diffused value of an object. In other words, light colored objects return a higher percentage of light than do darker colored objects.
Using this photograph of the billiard balls, we can see that they have the same intensity specular highlight but the difference in the tonal efficiencies of the diffused values between the colored and black balls produced different levels of contrast between the diffused and specular. The black billiard ball has a higher degree of contrast between the diffused and specular than does the lighter tone ball. Therefore, we can see that darker objects will produce a higher degree of contrast between the diffused value and specular highlight than do lighter objects.
To review the final section of light control, the controls of contrast between the diffused value and specular highlight are the size of the light source, the distance from the light source to the subject, surface efficiency and tonal efficiency.