FFP reticle sights

1st focal plane (FFP)

— the reticle of an optical sight (see "Type"), located in the so-called first focal plane — roughly speaking, in the area of \u200b\u200bthe lens.

This feature is found only in models with multiplicity adjustment (see "Functions and Capabilities"). Devices with FFP differ from similar models with a grid in the second focal plane (SFP) in that when the magnification changes, the apparent size of the grid also changes proportionally — when the magnification is doubled, the grid also becomes twice as large, etc. Due to this, the angular the dimensions of individual grid elements (for example, the distance between two adjacent mil-dot points) remain unchanged regardless of the selected multiplicity. And this, in turn, means that it is possible to determine distances by angular dimensions and take corrections “on the go” according to the same rules, regardless of the degree of increase. The main disadvantages of FFP are complexity and high cost. It is also worth noting that for "hunting" nets without goniometric elements, the described advantages are simply not relevant, so the first frontal plane is practically not used for them.