I measured the depth of focus of our low magnification microscope.
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Case 01
Model used Lens: Low magnification lens SDS-LRS Camera: 5 MP USB camera
Taking an object at an angle of 60 ° |
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I took a picture by tilting the gold scale to 60 °.
The aperture of the lens is open.
The depth of focus is not an objective number but it is a subjective value.
90 mm X sin 60 ° = 78 mm.
In the vertical direction, the focal depth is 78 mm.
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This low magnification lens has |
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If you close this aperture, the depth of focus will deepen.
Since the focus is on the whole screen, this method can not calculate accurately. But it will be over 100 mm.
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Case 02
Model used Lens: Low magnification lens SDS-LRS Camera: 5 MP USB camera
Taking an object at an angle of 45 ° |
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| 1．Set 20.0 mm x 15.0 mm as the field of view (about 20 times) | |
 Open |
 Close |
| In same 20 times level, shoot a board carrying a capacitor with a height of 20 mm | |
 Open |
 Close |
| 2．Set to 10.0 mm x 7.5 mm field of view (about 40 times) | |
 Open |
 Close |
| In the same 40 times, shoot a board carrying a capacitor with a height of 8 mm | |
 Open |
 Close |
The depth of focus decreases since the magnification increases.
You can adjust by using the aperture.
However, increasing the amount of narrowing will cause the image to become dark, so it is necessary to significantly increase the amount of light.
You can cover it to some extent by adjusting items such as “Brightness” “Gain” “Exposure” on the camera side.
