All Petzval lens elements are multi-coated in a special formula to protect them. However, we cannot disclose the full details of the materials due to industry standards.
Like most manual lenses, the Petzval is not weather/waterproof. However, to prevent dust particles getting into the aperture slots, there is a lining material to cover the Waterhouse aperture slots. The Lens also comes with a special ‘blank’ aperture ring which can be inserted to cover the aperture slot when the lens is not in use.
The lens can also be taken apart to clean inside if any dust happens to get in; however, we recommend that this type of lens cleaning is only done by a qualified lens technician to avoid damage to your wonderful lens.