Quick Overview The Xume 49,52,58,67,82mm Filter Holder is a precision-machined metal ring that attaches to a 49mm circular screw-in filter to provide instant and secure attachment to lenses when a Xume Lens Adapter is installed. NdFeB rare Earth magnets are integrated within lens adapters to attach to the filter holder to and provide a strong, but easy to remove, connection that is suitable for use with oft-used filters. By using quick-to-remove magnets to attach filters, changing of filters can occur much more quickly and eliminates the chance of cross-threading or jamming when installing or removing filters. The ring is approximately the same thickness as most step-rings and will not cause vignetting on most lenses with focal lengths as wide as 24mm (35mm equivalent). Over-the-lens type lens hoods are still compatible when Xume Adapters and Holders are in place and are recommended during use to provide an even more assured connection if working in busy environments. Traditional snap-on lens caps are not directly compatible with Xume lens adapters. To protect the front element of a lens that is not in use, but has a Xume lens adapter installed on it, a Xume filter holder can be first connected to a snap-on lens cap. The combination of a snap-on lens cap and a Xume filter holder can then placed over the lens instead of a filter with a Xume filter holder. Alternatively, a Xume lens cap designed to cover a correspondingly-sized Xume lens adapter may be used instead.