Parallax means the direction in which the target point can be seen differs depending on the position of the observation point at two points.
Telecentric lenses with less distortion due to parallax.
Observe the following sample with different lenses.
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Observe the sample on the right by changing the lens Field of view 60 X 40 mm Pillar height 60 mm |
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| ●Observe by telecentric lens | |
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| ●Observe with other lens | |
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<2. There is no expansion / contraction of the image within the depth of focus>
| ●Observe by telecentric lens | |
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Observe from the point that the focus is perfectly matched to ± 3 mm (Within depth of focus) |
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When the focal length is 105 mm (Focus is perfectly matched)
The left photograph is the one which measured the diameter of the circle of the object. Let’s change the focal length while keeping the diameter size and the circle display (red line). |
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Focal length 108 mm (A status in which the lens is raised 3 mm upward from the distance where the focal point is perfect)
You can see that there is no deviation between the circle display (red line) and the circle of the object. There is no expansion and contraction of the image within the depth of focus. |
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Focal length 102 mm (A status in which the lens is lowered 3 mm downward from the distance where the focal point is perfect)
You can see that there is no deviation between the circle display (red line) and the circle of the object. There is no expansion and contraction of the image within the depth of focus. |
| ●Observe by other lens | |
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The left photograph is the one which measured the diameter of the circle of the object. Let’s change the focal length while keeping the diameter size and the circle display (red line). |
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Focal length 107 mm (A status in which the lens is raised 3 mm upward from the distance where the focal point is perfect)
You can see that there is a gap between the circle display (red line) and the circle of the object. The image is contracting. |
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Focal length 101 mm (A status in which the lens is lowered 3 mm downward from the distance where the focal point is perfect)
You can see that there is a gap between the circle display (red line) and the circle of the object. The image is swelling. |
We have various of telecentric lenses available.
Please check this out for details. → Telecentric lens
