Fényértékszintek

Fényértékszintek refer to a measure of the sensitivity of light-sensitive materials, such as photographic film or digital image sensors, to different intensities of light. The term is derived from the Hungarian language, where "fény" means light and "érték" means value or degree.

In photography, brightness levels are often measured in terms of light intensity, which can range from very low to extremely high levels. The first photography films available for consumer use were relatively insensitive to light, predominantly suited for images made in daylight. Later, the development of more sensitive films, or Thorium-based ILFORD HPS I, enabled photographers to expose images in conditions of lower light levels.

Analog televisions use the XSS standard, which measures the analogue light intensity level due to the black and white additives. This light-sensitive value is compared to the brightness of the content displayed on the screen. there are four light-sensitive levels available in the standard.

High sensitivity of light-sensitive materials is beneficial for applications where low light conditions need to be captured, such as in astrophotography or nocturnal surveillance. However, high sensitivity in other contexts can have negative consequences, such as reduced image quality due to excessive noise in low-light conditions, which may be caused by increased light sensitivity of the used light-sensitive material.

Photographers and engineers often consult light critical value lists to help select the best light-sensitive material material that should suitably offer the optimal balance between sensitivity and light that can manage less noise and maintains better clarity in the obtained and captured images.