Baader ND 1.8 (OD=1.8 T=2%) 2 inch Neutral Density Filter

Cutting light by 6.7 f-stops with an optical density of 1.8 and just 2% transmission, this 2-inch neutral density filter from Baader Planetarium tames extreme brightness for astrophotography and high-intensity imaging without shifting colour balance.

Overview

The Baader ND 1.8 filter is engineered for demanding optical applications requiring significant attenuation of incoming light. Constructed with a finely polished optical substrate and multi-coated with Baader's proprietary anti-reflection coatings, it maintains high transmission uniformity across the visible spectrum. The filter cell is machined from lightweight, anodised aluminium, ensuring durability and a secure fit in any 2-inch (M48) threaded system. Whether used for photometry, high-speed video astronomy, or simply reducing brightness for visual observation of the Moon, this filter provides consistent, neutral density performance.

What stands out

• Optical density 1.8 (transmission 2%) – equivalent to 6.7 f-stops of light reduction
• 2-inch (50.8mm) standard filter thread (M48 x 0.75) for broad compatibility
• Multi-coated surfaces to minimise internal reflections and ghosting
• Neutral spectral transmission – no colour shift, ideal for true-colour imaging

Technical details

• Filter size: 2 inch (50.8 mm)
• Optical density: 1.8
• Transmission: 2%
• Light reduction: 6.7 f-stops
• Thread: M48 x 0.75
• Substrate: Finely polished optical glass
• Coatings: Baader proprietary anti-reflection multi-coatings
• Cell material: Lightweight anodised aluminium

Our verdict

A precision tool for serious imagers who need heavy neutral density without compromising colour fidelity or introducing reflections. The Baader ND 1.8 delivers consistent, repeatable performance in a robust 2-inch cell.