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Normal machine vision lenses exhibit varying magnification for objects at different
distances from the lens. This causes several problems for machine vision error
proofing and
other applications:
- the apparent size of objects changes with distance from the camera
- some features or objects may be hidden by objects that are closer to the
lens
- the apparent shape of objects varies with distance from the center of the
field of view (FOV). Objects appearing close to the edges are viewed from an
angle, while objects near the centre of the FOV are viewed frontally (circles
near the centre of the FOV become ellipses when moved towards the periphery).
Telecentric lenses, on the other hand, have the same magnification at all
distances. An object-space telecentric lens creates images of the same size for
objects at any distance and has constant angle of view across the entire field
of view. An object that is too close or too far from the lens may still be out
of focus, but the resulting blurry image will be the same size as the
correctly-focused image would be.
Because their images have constant magnification and geometry, telecentric
lenses are often used for metrology applications (among other applications),
when a machine vision system must determine the precise size of objects
independently from their position within the FOV and even when their distance is
affected by some degree of unknown variations. These lenses are also commonly
used in optical lithography, for forming patterns in semiconductor chips.
Navitar offers a family of high-performance telecentric lenses for use in
machine vision, metrology, and precision gauging applications. All provide low
optical distortion and a high degree of telecentricity for maximum, accurate
image reproduction, particularly when viewing three-dimensional objects.
One of the most important benefits of a telecentric lens is that image
magnification does not change as object distance varies. A telecentric lens
views and displays the entire object from the same prospective angle, therefore,
three-dimensional features will not exhibit the perspective distortion and image
position errors present when using a standard lens. Objects inside deep holes
are visible throughout the field, undistorted, therefore, telecentric lenses are
extremely useful for inspecting three-dimensional objects or scenes where image
size and shape accuracy are critical
Our machine vision lenses include the 12X Telecentric Zoom lens, TC-5028
telecentric video lens, Invarigon-R™, Macro Invaritar™, ELWD Macro Invaritar™,
and Invaritar Large Field telecentric lenses. Click on the links to the left to
view specific lens information. Then, select the telecentric lens that will
provide you with the best image possible for your machine vision, gauging, or
inspection requirements. If you need further technical assistance or
information, please contact us. Our application engineers will be happy to
assist you every step of the way in selecting the lens that is perfect for your
application.
Specifications:
| Mag. |
Telecentric
Error (degrees) |
Object
N.A. |
Image
N.A |
Object
Depth of Focus (mm) |
Telecentric
Error (mm) |
Object
Size |
Approx.
MTF (Ip/mm) |
Resolvable
Features (microns) |
| 1/4"
Format |
1/3"
Format |
1/2"
Format |
1/4"
Format |
1/3"
Format |
1/2"
Format |
1/4"
Format |
1/3"
Format |
1/2"
Format |
| 0.16 |
0.05 |
0.06 |
-0.03 |
0.005 |
0.032 |
38.8 |
0.018 |
0.020 |
-0.009 |
25.0 |
37.3 |
49.7 |
15 |
33 |
| 0.23 |
-0.10 |
-0.09 |
-0.18 |
0.007 |
0.031 |
19.4 |
-0.017 |
-0.016 |
-0.030 |
17.4 |
26.1 |
34.8 |
22 |
23 |
| 0.33 |
-0.19 |
-0.18 |
-0.27 |
0.010 |
0.030 |
10.3 |
-0.016 |
-0.016 |
-0.024 |
12.1 |
18.2 |
24.3 |
30 |
17 |
| 0.47 |
-0.23 |
-0.23 |
-0.31 |
0.013 |
0.028 |
6.0 |
-0.012 |
-0.012 |
-0.016 |
8.5 |
12.8 |
17.0 |
39 |
13 |
| 0.67 |
-0.25 |
-0.25 |
-0.34 |
0.016 |
0.024 |
3.8 |
-0.008 |
-0.008 |
-0.011 |
5.9 |
8.9 |
11.9 |
49 |
10 |
| 0.96 |
-0.27 |
-0.27 |
-0.36 |
0.020 |
0.021 |
2.6 |
-0.006 |
-0.006 |
-0.008 |
4.2 |
6.3 |
8.4 |
59 |
8 |
| 1.36 |
-0.29 |
-0.29 |
-0.38 |
0.024 |
0.017 |
1.8 |
-0.004 |
-0.005 |
-0.006 |
2.9 |
4.4 |
5.9 |
71 |
7 |
| 1.94 |
-0.25 |
-0.24 |
-0.29 |
0.028 |
0.015 |
1.3 |
-0.003 |
-0.003 |
-0.003 |
2.1 |
3.1 |
4.1 |
84 |
6 |
|
Distortion
< 0.1% for all magnifications. Working Distance =
188 mm for all magnifications. |
Additional Resources:
For further information, please peruse through Navitar's
Telecentric Lens Brochure (PDF).
| Available Options Below. Call us or e-mail us for custom options. |
| 12X Telecentric: |
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| C-Mount Invaritar Large-Field Base Lenses: |
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| CCTV Telecentric: |
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| ELWD Macro Invaritar Telecentric Lenses: |
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| F-Mount Invaritar Large-Field Base Lenses: |
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| Fiber Bundle Collimator: | ($665.00) |
| Invarigon-R Telecentric Lenses: |
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| Invaritar Large-Field Attachment Lenses: |
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| Macro Invaritar Telecentric Lenses: |
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| Mounting Brackets: |
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| Right Angle Attachments: |
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| Teleconverters & Adapters: |
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