Figure of Merit, also known as FOM, is the result of multiplying a tubes center resolution and signal to noise ratio values together. FOM is used as a primary benchmark for tube performance and export control.
Omni VIII contract specs indicate a 64 lp/mm minimum center resolution and a 25 signal to noise ratio minimum. This is the lowest current Milspec requirements indicating a minimum FOM of 1600 to meet minimum Omni VIII Milspec requirements. Tubes with a FOM value lower than 1600 cannot pass as US Milspec Omni VIII intensifiers. It is important to note that there are several performance requirements other than FOM for a tube to be considered a Milspec tube, however, FOM is a great starting point for gauging tube performance.
At Licentia Arms Co. we believe that there are three major FOM performance benchmarks that end users can use to judge what system is right for them. The three benchmarks are a 1792, 2000, and 2376 minimum FOM. Although these benchmarks are not everything they can be used to determine what price point and performance level is a good fit.
A 1792 minimum FOM tube is going to be a solid milspec tube. Although it will not be of the performance level of a 2000 plus FOM tube, the performance level will be to the point where the customer is still getting a solid system that will perform well in most lighting conditions. Where users are sacrificing at this level is extreme low light. This level of tube will have more noise when light levels are extremely low and need supplemental IR.
A 2000 minimum FOM tube is going to be a high performing tube. This level of tube is going to be the most value price wise when factoring the price jump from a 1792 minimum FOM performance level and the performance gains. The performance gains at this level will be noticeable in low light performance and image quality.
The 2376 minimum FOM benchmark is an absolutely phenomenal tube and the highest minimum FOM offered outside of the SOCOM / MIL markets. This level of tube is for the customer who wants the absolute best. These tubes perform incredibly well in all lighting conditions including extreme low light. This level of tube will perform in a much wider spectrum of low light conditions without the need of supplemental IR. Users will notice the upmost image quality with very fine details that are able to be distinguished at farther distance over other FOM levels. Users will also notice the upmost performance in extreme low light conditions.