For accurate product deployment, high-quality images have become crucial for any manufacturing or developing organization. Besides manufacturing, lens quality is important to generate a good picture for the product’s promotion, so choosing the right lens combination is impactful.
Good machine vision lens influence a variety of other things, including the speed at which the analysis may be completed, the measurement precision, and the repeatability and reliability of the downstream analysis. Below are some tips to be considered for choosing a perfect lens.
What are machine vision lenses?
The lens collects the picture and sends it to the camera’s image sensor. The optical quality and pricing of lenses vary; the lens used influences the quality and resolution of the acquired image. Most vision system cameras come with two types of lenses: interchangeable and fixed. C-mounts and CS-mounts are the most common interchangeable lens mounts.
Varieties of Machine Vision Lenses
- Fixed focal lenses:
Fixed focal length lenses are known by various names, including prime lenses (popular in photography or cinematography), FA lenses (where FA often stands for factory automation), and machine vision lenses. They are the most frequent types of lenses used in machine vision; if a lens is referred to as a single focal length (e.g., a 25mm lens), it is most likely a fixed focal length lens. Most of the time, fixed focal length lenses are best suited for general components inspection, barcode reading, biometric and document scanning, license plate reading, and other optical character recognition (OCR) or optical character verification (OCV). The AFOV of a fixed focal length lens is determined by the focal length of the sensor size. The AFOV of a lens rises as its focal length decreases.
- Zoom Lenses:
Whereas fixed focal length lenses have a fixed AFOV, zoom lenses may adjust their focal length and hence their AFOV. Zoom lenses are appropriate for applications that demand the most flexibility and do not require high resolution; unless a FOV actively changes while imaging, it is likely not the best choice. Stepper motors are necessary for this scenario to alter the focus length rapidly and accurately. Zoom lenses are designated by zoom ratios, which may be calculated by dividing the greatest focal length choice by the lowest for any specific lens.
- Telecentric Lenses:
Telecentric lenses should be employed if a high precision measurement in a system is required. They are highly specialized, fixed magnification lenses with extensive optical capabilities. The selection of a telecentric lens is sometimes assumed to be more difficult than that of a fixed focal length lens, yet this is virtually never the case.
A lot of conditions need to be considered while choosing a lens. Some common factors include optical resolution, structure details, the application area, the industry in which it would be used, etc. Apart from all other aspects, optical quality is the most important factor that needs to be considered. Choosing a lens without certain examinations can be a loss and tiring exercise.