1) What is EggCalc?
EggCalc is an interactive tool designed to provide comprehensive data about the distribution of light from large diffusers when using Lighttools Original Soft Egg Crates or CUfocus Soft Egg Crates and when not using egg crates.
2) Why should I use EggCalc?
EggCalc is a quick and easy way to determine which soft light control tool (egg crate) will be the best choice for your lighting preferences.
3) How were the values in EggCalc determined?
EggCalc data has been verified by controlled light measurements and theoretical analysis using an evenly diffused light and various models of egg crates.
4) What are Original Soft Egg Crates and what purpose do they serve?
Original Soft Egg Crates are made of uniform parallel cells that control off-axis light at right angles to the diffuser. A secondary effect is that Original Soft Egg Crates reduce the near-to-far light ratio, creating a more uniform lighting, which is ideal for a subject that is moving towards or away from the light. This more uniform lighting occurs due to increased occlusion by the cells at near distances.
The benefits of using Original Soft Egg Crates are:
* they block off- axis light in four directions
* they reduce variation in near-to-far light values
* they create separation and depth
* they eliminate spill and flare
* they reduce setup and teardown time, requiring less manpower and grip equipment
* they are easy to transport
* they store easily
* they allow the user to spend more time on lighting design
5) What are CUfocus Soft Egg Crates. and what purpose do they serve?
CUfocus Soft Egg Crates are made up of specially angled cells that provide full-source illumination at near distances. These angled cells also tightly block light around the desired subject, avoiding spill in the most confined spaces. Full-source illumination at near distances is not possible with Original Soft Egg Crates due to occlusion.
The advantages of using CUfocus Soft Egg Crates are:* they are the only tool that allows for tight light blocking around the subject at near distances to the source
* they reduce setup and teardown time, requiring less manpower and grip equipment
* they are easy to transport
* they store easily
* they allow the user to spend more time on lighting design
6) How do I choose between Original Soft Egg Crates and CUfocus Soft Egg Crates?
Original Soft Egg Crates:* When occlusion is not a concern,
* When you want the light to be blocked around a larger area
* When you want to reduce near-to-far exposure values.
* When you want to eliminate all occlusion to obtain maximum soft light quality on the subject area,
* When you also want to achieve dramatic light blocking around that subject area.
7) What is occlusion
Occlusion is the blocking of light from the source to the subject due to the angle of Soft Egg Crate cells. This changes light distribution and the effective size of the light source, thereby affecting the softness of the light. The degree of soft light achieved depends on:
* the size of the diffuser
* the distance between the diffuser and the subject
Read more about occlusion here.
8) In describing the CUfocus models, what is meant by CU 0.75, CU 1.0, and CU 1.25?
These designations describe the sweet spot or focus distance, based on the diagonal dimension of the diffuser. The focus point is the point at which there is most no occlusion (the same effect as if no egg crate were installed), while at the same time achieving controlled, tight blocking of light around the area.
CUfocus 0.75 models are the most readily available.
Table: Diagonal Dimensions for Softboxes and Butterfly and Overhead Frames:
Softboxes |
Butterfly and Overhead Frames |
||||||
Diffuser Size |
1.0x |
0.75x |
0.5x |
Diffuser Size |
1.0x |
0.75x |
0.5x |
24" x 32" |
3'4" |
2'6" |
1'7" |
4' x 4' |
5'8" |
4'2" |
2'10" |
36" x 48" |
5' |
3'9" |
2'6" |
6' x 6' |
5'6" |
6'5" |
4'2" |
54" x 72" |
7'6" |
5'8" |
3'9" |
8' x 8' |
11'4" |
8'6" |
5'8" |
36" (Octa) |
36" |
2'3" |
1'6" |
8' x 12' |
14'5" |
10'10" |
7'2" |
60" (Octa) |
60" |
3'9" |
2'6" |
12' x 20' |
23'4" |
17'6" |
11'8" |
84" (Octa) |
84" |
5'3" |
3'6" |
20' x 20' |
28'4" |
21'2" |
14'1" |
9) What is the meaning of the different occlusion colors and of the corresponding exposure changes used in EggCalc, and how are they shown in the Light Loss Chart?
The percentage of occlusion shown in the graph represents the amount of light blocked by the cells. This percentage also represents the size reduction of the effective light source.
10) How do I compare exposure values from the selected centre axis to any off-axis point?
This information is displayed in the third column of the Light Loss Chart by moving the cursor (green dot) to any selected point on the graph (red dot). The exposure difference takes into account both occlusion and attenuation (which is the natural decrease of light when measured off center axis).
11) What is the meaning of the dynamic green numbers that change with movement of the cursor on the graph?
The horizontal number shows the offset distance from the centre axis and the vertical number shows the distance from the red line.
Welcome to EggCalc, an exposure calculator that makes it possible to easily compare lighting results using an evenly diffused source with the following Soft Egg Crates:
Lighttools Original, Lighttools CUfocus, and a diffused light without soft egg crates
EggCalc easily shows exposure variations from center axis (red dot) to any selected point off center axis (green dot). EggCalc provides this information for Lighttools models at selected distances and most diffused light source sizes.
We have worked diligently to make EggCalc easy to use and understand. EggCalc data has been verified by controlled light measurements and theoretical analysis using an evenly diffused light and various models of egg crates. We will continue to improve the functionality of EggCalc software as we receive feedback and suggestions. Feedback
Basic definitions:
Original Soft Egg Crates Uniform parallel cells block off-axis light and reduce near-to-far light ratios.
CUfocus Soft Egg Crates Specially angled cells set to a predetermined distance point provide full-source illumination at close distances and dramatically block off-axis light.
Occlusion Occlusion is the blocking of light from the source to the subject due to the angle of Soft Egg Crate cells; this occlusion increases at close distances.
Off-axis Moving off the center axis line-to the left or right, or higher or lower-is referred to as being off-axis.
Choosing between Original Soft Egg Crates and CUfocus Soft Egg Crates?
Original Soft Egg Crates:
* when occlusion is not a concern
* when you want the light to be blocked around a larger area,
* when you want to reduce near-to-far exposure values.
CUfocus Soft Egg Crates:
* when you want to eliminate all occlusion to obtain maximum soft light quality on the subject area,
* when you also want to achieve dramatic light blocking around that subject area.
Instructions:
To begin, choose the diffuser size (2' x 3' to 20' x 20'), the CUfocus model (x0.75, x1.0, x1.25), the cell degree (20° to 60°) and the distance from source. Then select the flashing Calculate! button.
CUfocus model (x0.75, x1.0, x1.25) This distance describes the sweet spot or focus distance, based on the diagonal dimension of the diffuser. The focus point is the point at which there is no occlusion (the same effect as if no egg crate were installed), while at the same time achieving controlled tight blocking of light around the area.
Calculate Clicking on the flashing Calculate! Button generates the data for the selected distance from source on center axis (red dot).Reset Pushing the Reset button changes the distance to the correct focus point to match the selected CUfocus model.
To understand the meaning of the values generated in the Light Loss Charts, please consider the following:
Occlusion % on centre axis:
EggCalc calculates the amount of occlusion on center axis. This number can be seen in the second column of the Light Loss Chart for Original and CUfocus Soft Egg Crates. The occlusion equates to the light loss that takes place when the egg crate is used.
Occlusion increases greatly at closer distances and decreases at further distances. The occlusion % data in the fourth column relates to the specific distance set in EggCalc on center axis only.
Exposure difference from centre axis to any off-axis point:
This information is displayed instantly in the third column of the Light Loss Chart by moving the cursor (green dot) to any selected point on the graph (red dot). The exposure difference takes into account both occlusion and attenuation (which is the natural decrease of light when measured off center axis).
The percentage of occlusion shown in the graph represents the amount of light blocked by the cells. This percentage also represents the size reduction of the effective light source.
The green horizontal numbers show the offset distance from the centre axis and the vertical numbers show the distance from the red line.
