84.5mm Strong Neutral Density Graduated Filter -
The 84.5 mm Strong Neutral Density Graduated Filter is designed to reduce exposure of the upper (darkened) part of the filter, used to reduce highlights/overexposure of the upper part of image/sky. The human eye has a much greater dynamic range than photographic film or CCD/CMOS digital sensor/digital back (dynamic range means the ability to visualize a wide range from darkest to lightest shades of the light).
Because of this fact, it often happens that high dynamic scene that is seen by simple human eye after shooting with camera lose most of its dynamic range; for example, dramatic textured clouds are on the digital photo visible only as a large white area, in photographic terminology: "over-exposed area." Upper part of the image is very light and lower part is very dark.
This negative fact is present because digital sensor or film cannot record images with a large dynamic range such as a human eye. Due to this, a photograph taken outside (outdoor) is sometimes useless when a filter is not used. And that is why almost all outdoor photographers (landscape, architecture or nature photographers) use filters so-called gradual ND filters (Neutral density filters).
The neutral density filter is a neutral gray color, which reduces the amount of light passing through a filter and neutrally darkens the upper part of image as far as possible without affecting its color tone (neutrality). The result is often stunning - "blow" the sky will disappear, the sky and cloud structure becomes visible, three-dimensional lattice while the very bottom (landscape) remain ideal exposed (not over-exposed, not dark). Moreover, the effect is very natural and the use of the filter is not noticeable.
- While ordinary plexiglass or resin materials can be relatively easy to scratch, organic glass is completely a different case. Filter material is characterized by extremely high scratch resistance and common materials such as fingernails and sharp objects make it almost impossible to scratch
- The material used in these filters (84.5mm) achieves the best features in a variety of other optical parameters such as Abbe number with a value of 58, guaranteed minimum (hardly any) negative impact on the chromatic aberration (which is often a negative phenomenon cheap lenses) and more
- Materials which are used in various areas of the military and aviation are usually known as the toughest, highest quality and often unavailable to the general public. Organic glass is used in the manufacture of filters and are also commonly used in military aircraft to cover the cockpit
- The material used for the production of 84.5mm filters is commonly used worldwide for the production of corrective eyeglasses, which shows the extraordinary optical properties. While conventional optical glass was used in eyeglasses in the past
- Most ordinary glass breaks easily when it falls on the ground/floor, but organic glass is very flexible. Due to the glass being flexible, if dropped on the ground/floor or you or handle insensitively, it most likely will not break or shatter