Telecentric lens
Telecentric lenses allow you to obtain images with less distortion.
I experimented with our telecentric lenses RT3 and RT5.
|  | Telecentric lens RT3, RT5 Attach it to the USB camera. I took a photo of the glass scale. | 
|  |  | 
| Photographed with telecentric lens RT3 | Photographed with telecentric lens RT5 | 
| You can see that there is no distortion in the four corners of the screen. This is the feature of telecentric lenses. | |
CCTV lens
If you are using a CCTV lens, a telephoto lens will have less distortion than a wide-angle lens.
I experimented with a 6mm fixed focus lens and a 25mm fixed focus lens.
|  | I attached an 8mm fixed-focus lens to a USB camera and took a picture of graph paper. | 
|  | It is evident that the four corners of the graph paper are distorted. | 
|  | “I attached a 25mm fixed-focus lens to a USB camera and took a picture of graph paper.” | 
|  | There isn’t much distortion observed at the four corners of the graph paper | 
If it’s a macro lens, some lenses have less distortion depending on their performance, but they tend to be more expensive as a result.
Summary:
– By using a telecentric lens, you can obtain images with minimal distortion.
– The characteristic of a telecentric lens is that there is no distortion even at the four corners of the screen.
– If you are using a CCTV lens, using a telephoto lens rather than a wide-angle lens will result in less distortion.
	– The characteristic of a telecentric lens is that there is no distortion even at the four corners of the screen.
– If you are using a CCTV lens, using a telephoto lens rather than a wide-angle lens will result in less distortion.



