Heliopan 77mm Digital Filter (707786) with specialty Schott glass in floating brass ring Heliopan's premier 77mm Digital Filter has been specifically designed for digital cameras. It was constructed to be highly resistant to UV and infrared radiation, which results in greater color separation, color contrast and tone. Also, this Digital Filter performs exceptionally well under artificial lighting. Constructed from the highest German Schott Optics, which guarantees incredible optical resolution. Our glass is specially ground and polished to minimize internal reflections, while ensuring that the quality of your images are not degraded by using our optics in front of your lens. It is also specially hardened to resist most impacts. Our standard 8-Layer Multi-Coating minimizes reflections and does not interfere with the resolution of your camera optics. Our precision cut brass ring ensures a secure and sturdy fit, are more resistant to side impacts, and less likely to bind or cross-thread after extended use. We do not source any materials outside of Germany in the assembly and construction of our products. All raw materials are prepared and hand-assembled in our factory and do not leave our facility until they are completely inspected by our quality technicians.