The MidOpt 40/20 Scratch-Dig Standard

Most MidOpt filters are designed with a 40/20 scratch-dig ratio. What exactly does this mean in terms of your image results? Surface quality is important for optimal image results

Midwest Optical Filters Dark Red Bandpass Filter, 30.5 mm Thread

Midwest Optical Filters Blue Attenuation Filter, 34 mm Thread

Understanding Surface Quality: A Practical Guide, Test & Measurement

Uniforce Sales and EngineeringMidOpt Filters - Uniforce Sales and Engineering

Training Archive

MidOpt PC052-82 Circular Polarizing Filter

Midwest Optical SP625

Product - Bandpass Filters

Scratch / Dig Specifications - Mark Optics

MidOpt Polarising Filters