What are the trade-offs when specifying an HD or UHD lens?
Vision and imaging systems typically comprise a camera, imaging sensor and lens working together to provide a working solution. For them to work optimally, all the components must be matched properly. The earlier in the process of designing a vision or imaging system you choose your optics the better.
From a vision or imaging system perspective the main difference between UHD and HD is the pixel count: High Definition (HD) usually refers to 1280×720 pixels, while Ultra High Definition (UHD) means 3840×2160 pixels. This means that UHD offers approximately nine times more pixels than HD. Consequently, the key reason for specifying a UHD vision or imaging system is that the higher resolution delivers enhanced clarity and detail plus superior performance on large displays. However, UHD lenses and related UHD technologies are more expensive than their HD counterparts and not always required on smaller displays.
When specifying a suitable optical lens for your vision or imaging application – resolution is best stated as the Nyquist of the sensor (Cycles) or in terms of MTF (Modular Transfer Function). By knowing the dimensions of the imaging sensor and its pixel pitch, we can ascertain what resolution is required from your lens to deliver optimal performance. It is important therefore not to specify a lens resolution that is greater than the Nyquist of the sensor as this just results in an optical design that is more expensive due to the requirement for additional elements, exotic glass types and a more complex design.
Read white paper: ‘Sensor resolution versus lens resolution.’