Hoya HMC NDX4 Filter

Neutral Gray Filter ND X 4:

• Shutter speed extension or aperture opening: by 2 stops
• Apparent sensitivity change: quartering, e.g., from ISO 800/30° to ISO 200/24°
• HMC (Hoya Multi Coated): The multi-coated filters are known for their extremely low reflections on their glass surfaces, which further suppresses stray light and ghosting.
• Filter diameter: 49 mm

Neutral gray filters are often overlooked by many photographers, but they can be very useful in certain situations and provide results that would otherwise be impossible. ND filters (Neutral Density) appear gray and reduce the amount of light reaching the film without affecting color balance. They have four main applications:

1. They allow for long shutter speeds even with higher sensitivity films to capture motion, such as in waterfalls and streams, fountains, clouds, or moving cars.
2. They enable larger apertures for shallower depth of field, helping to distinctly separate a subject, such as a portrait, from its background.
3. They act as if the film sensitivity has been reduced, allowing even high-sensitivity films (i.e., over ISO 400/27°) to be used in bright daylight.
4. They enable correct exposures in bright environments like snow and sandy beaches or under extremely bright lighting with film and video cameras that do not have adjustable shutter speeds, preventing overexposure.