The high ND density is achieved with a special coating process. Color reproduction is optimized over the entire visible light spectrum, making subsequent image processing simpler and faster for the photographer. Thanks to their high-grade, anti-reflex and hardened final coating, which is not only scratch-resistant, but also dirt and water repellent, these square filters can be cleaned very efficiently and quickly. The optical density ND 4.5 is equivalent to +15 f-stops. In practice, this means that the exposure time at 1/60s without the filter increases to 8 minutes with the filter.
The square filter is available from retail camera stores under article number 1093504 for a RRP of €189.00.
For further information, see www.schneiderkreuznach.com