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The concept of diffusing light to control image contrast is the focus of this lesson. This is where the birth of the soft box came from. By controlling the raw light with a large fabric reflector then applying levels of diffusion material inside, this reflector gave photographers a level of control, portability and convenience unheard of in the past.

You can take several avenues in applying this concept to your images. In this lesson, we will look at the soft box in all its configurations and explain how and why this concept works so well, then take it a few steps farther. We will apply secondary diffusion in front of the soft box to further control the contrast range.

 

Topics Covered:

  • The soft box as a "hard" light
  • The soft box as a "soft" light
  • Double diffusion with a soft box
  • Triple diffusion with a soft box

Equipment Used:

 

Lighting Equipment

  • LiteDisc® accessory: LiteDisc® holder
  • LiteDisc®: 32 inch white/silver
  • LitePanel accessory - Connector Clips
  • LitePanel accessory - Main & T Clamp
  • LitePanel fabric: 39x39 inch Translucent
  • LitePanel frame: 39x39 inch Aluminum
  • LiteStand: large
  • StarLite®: medium digital kit

When we talk about contrast, we are talking about the range of tones from the brightest to the darkest part of an image. To control this range, we need to control the light we put on the subject.

As we go through this lesson, we will apply the controls available from a soft box and from secondary diffusion placed in front of the soft box. In each of the steps, we will explain the concept and show the results.

Because this lesson is about contrast control, we chose subjects with a wide contrast range, the knife set offers both black in the block and bright highlights in the steel of the knives.

As we go through the steps of the lesson, you will see how softening the light with layers of diffusion material controls the light ratio and improves our photo with each step.

 

The Soft Box as a "Hard" Light

Our first step is to set up the Medium Starlite Kit.

The configuration of the light for this step will be without both the internal baffle and diffusion face of the soft box, effectively creating large reflector. This will produce a "hard" or "high-contrast" light output.

We placed the light on the right side of the set in the vertical position so that the bottom edge of the box was at table height and at 90 degrees to the subject. We also set up a 32-inch white LiteDisc reflector as our fill. The positioning of the main light and fill reflector will remain a constant throughout the lesson (figures 1, 2, and 3).

Note: Assembly instructions for this light kit are available on the Medium Starlite Kit page at photoflex.com.

Figure 1

 

Figure 2

Figure 3

 
 

With our light in position, we took a light meter reading and then set the camera accordingly (1/60 @ f/8.0). We then focused the camera and took the first shots

Our results image (figure 4) shows the “hard” quality of the light produced without any of the diffusion material installed in the soft box. We have a very broad contrast range that our digital camera cannot hold resulting in loss of detail in both the highlights and the shadows. The undiffused light also casts very hard shadows on the set surface next to the subject.

In figure 5, we have cropped in to clearly show the “dirty” highlights in the knife blade and on the black ceramic block. Without the diffusion installed, we see the interior of the soft box reflected in the blade and the block.

 
 

Figure 4

Figure 5

 

Softening the Light with a Baffle

For our next step, we installed the internal baffle. This is the first level of diffusion to soften the light output of the soft box (figures 6, 7, and 8).

For safety’s sake, we recommend that you switch off the light before you perform this action.

Figure 6

 

Figure 7

Figure 8

 
 

Since we have modified the light source, we took a second light meter reading and found we have lost 1/2 a stop of light (1/60 @ f/5.6-1/2). This is normal when adding diffusion to a light source. The diffusion material will decrease the amount of light that passes through.

We made adjustments to the exposure settings and took our second shot (figures 9 and 10).

In the result image for this step (figure 9), we see some improvement. The highlights on the knife blade look much cleaner and the contrast ratio has closed a bit. The shadows cast by the subject have softened quite a bit and we are starting to get the wrapping effect of the soft box.

However, we still are loosing detail at both ends of our contrast range. The logo on the blade that we saw in our first results now falls in the highlight created by the internal baffle and, due to the wide contrast range, has all but disappeared.

Our shadow detail has improved somewhat. This is apparent in figure 10 where the knife handle and the top of the block come together. We can also still see the interior of the soft box in our highlight on the ceramic section of the block.

 
 

Figure 9

Figure 10

 
 

In figures 11 and 12, we can compare both the softening of the highlights in the blade and the changes in the contrast range of the overall shot.

 
 

Figure 11

Figure 12

 

The Soft Box as a "Soft" Light

Our next step is to complete the assembly of the soft box by installing the diffusion face (figures 13, 14, and 15). The diffusion face will further soften the light output.

Figure 13

 

Figure 14

Figure 15

 
 

Since we have again made changes to the light source we took another meter reading (1/60 @ f/5.6). We found another 1/2 a stop of light was lost due to the added diffusion on the light. We made our adjustment to the exposure setting and shot the next image (figures 16 and 17).

In figure 16, we now see the light coming into control, our shadows cast on the background have softened and we really can see the wrapping effects of the diffused light.

In figure 17, we see that the contrast is now also in the range the camera can hold. The logo on the knife blade is now showing up with detail and we see better detail in the shadows on the product.

 
 

Figure 16

Figure 17

 
 

Here is a comparison of results using the soft box with just the baffle installed (figure 18) and the soft box with both the baffle and the diffusion face installed (figure 19). We can see how the added diffusion has controlled the contrast allowing detail in both the blade and in the darkest shadows to show up in our image.

Notice also how the highlight on the black ceramic is much more uniform in figure 19.

 
 

Figure 18

Figure 19

 
 

Double Diffusion with a Soft Box

The next steps required some set changes, so we temporally moved the soft box off the set and set up a 39X39 inch LitePanel with a diffusion (translucent) cover. Then we set up 2 - 2218 LiteStands and attached a Main and T clamp to each of them. We placed these stands to the right of the set about 40 inches apart, then secured the LitePanel to the stands using the Main and T clamps.

We set the height of the LitePanel so the bottom edge was just under the table level.This made the reflection in the knife and holder as seamless as possible.

We put the soft box back in position about 3 inches from the diffusion cover of the LitePanel (figure 20 and 21).

 
 

Figure 20

Figure 21

 
 

Since we have made some major modifications to our lighting set up, we took another meter reading (1/60 @f/4.0-1/2). Again, we have lost another 1/2 a stop of light, so we made our adjustments and shot a picture (figures 22 and 23).

Figure 22 shows the wrapping effect of the diffused light, the shadows cast by the subject has all but vanished with the double diffusion in place. Figure 23 shows our contrast control is also better, the details in both the highlights and the shadows are closer in value so the details on the blade logo are crisp and defined, while we still have clear detail in the shadows.

 
 

Figure 22

Figure 23

 
 

In figures 24 and 25, we can compare the improvements the secondary diffusion has made to our shot. As we add layers of diffusion to the lighting set up, we definitely reduce the overall contrast of the light. This is most apparent in the highlight on the knife blade, we can really start to see the details come through while our shadow detail is still looking very good.

 
 

Figure 24

Figure 25

 
 

Our next step is to simply move the soft box farther away to about 10 inches from the LitePanel. This allows the soft box to fully illuminate the diffusion screen and spread out and soften the highlights even more (figures 26 and 27).

 
 

Figure 26

Figure 27

 
 

Once again, we need to take a meter reading, but this time we set the shutter speed to two stops more than in previous readings, or to 1/15 second from 1/60 second. We did this because we were losing our depth of field as we set larger apertures to maintain our exposure level. Increasing our exposure time allows us to use a smaller aperture resulting in increased depth of field.

Our meter read 1/15 @ f/5.6-1/2 after making the adjustments, so we set the camera accordingly and shot the next picture (figures 28 and 29).

Figure 28 shows further softening of the cast shadows on the background, and more of the wrapping effect. In figure 29, we see better detail in the blade logo due to the increased softening of the light. The only drawback we see in this image is that, since we have moved the light away from the LitePanel, the edges of the panel have become more defined, causing the loss of the very soft edged highlights on the black ceramic block.

 
 

Figure 28

Figure 29

 
 

In figures 30 and 31, We can compare the shot with the soft box close (3 inches) to the LitePanel screen (figure 30) and the shot with the soft box farther (10 inches) from the screen (figure 31).

There is good detail in the logo once again. We see a marked improvement, in both the detail and the contrast range, from figure 30 to figure 31. In these results, we can also clearly see the hardening of the highlight on the ceramic block, due to the repositioning of the light farther away from the LitePanel.

 
 

Figure 30

Figure 31

 
 

Our next step requires the addition of a second 39X39 inch LitePanel, so we rolled the soft box off the set and assembled the second LitePanel with a diffusion (translucent) cover.

To attach this to our set, we installed a connector clip to the top and the bottom bar of the first LitePanel frame, then attached the second LitePanel to the connector clips. To get the maximum effect of softness we placed the diffusion cover on the backside of the second LitePanel. Once we had the two LitePanels set up, we rolled the soft box back into position about 3 inches from the second LitePanel (figure 32).

 
  • Figure 32

  • Figure 33

  • Figure 34


 

Since we made major changes to the lighting, we took another meter reading, adjusting the shutter speed to keep the aperture in the same range. Our reading was 1/30 at f/5.6, so we made our camera adjustments and shot the next image (figure 33 and 34).

Figure 33 shows the effect of the second LitePanel in softening our highlights and opening the shadows. Again this is apparent on the background in the shadow cast by the product.

Figure 34 shows that our blade logo has suffered some but is still looking good. We have very soft wrapping highlights in the ceramic block back again.

 
 

Figure 35

Figure 36

 
 

In figures 35 and 36, we can again compare the improvements in our lighting. We have gained some and lost some. Our gains came on the soft highlights without defined edges on the block and the loss, which is very little, to the detail in the blade and the logo.

 
 

Figure 37

Figure 38

 
 

For the last action, we moved the soft box back to 10 inches from the second LitePanel to allow the light to spread out and cover the entire diffusion screen of the LitePanels (figure 37).

 
  • Figure 39

  • Figure 40

  • Figure 41


 

With the changes made to the set, we took our last meter reading, adjusting the shutter speed to keep the depth of field in range (1/15 @ f/5.6). We then set the camera to the meter's reading and shot our last image (figures 38 and 39).

Figures 38 and 39 show the final results. We now have compressed the contrast into the perfect range for this shot. We see detail in all the highlights and shadows, plus our highlight in the ceramic block is soft and wraps around giving it a rounder look.

The detail in the knife blade is balanced and we have good detail in the logo. The shadow cast by the subject has really disappeared.

You may not need to take diffusion to this level to get details in the highlights and shadows of the product or person that you are photographing. However, this lesson shows the possibilities and the control of contrast you can have with diffusion.

 
 

Figure 42

Figure 43

 
 

In figure 38, our final image shows how using diffusion in multiple layers controls and improves the contrast of your images. Notice that you can clearly see the manufacturer's logo in the middle of the highlight on the knife. This is what is meant when photographers say they want details in the highlights.

Notice also, how the highlight in the black knife holder is very soft and natural looking and the holder appears round and three dimentional. This is what photographers mean when they say that they want details in the shadows.

Our last 2 figures show the progression of the steps we took in this lesson. Figure 40 shows the progression in results from modifying the light output of the soft box. Figure 41 shows the progression of adding double and triple diffusion.

 
  • Figure 44

  • Figure 45

  • Figure 46


  • Figure 47

  • Figure 48

  • Figure 49

  • Figure 50



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