Lens coating that eliminates reflections and ghosting, maximizing light transmission. Standard on modern quality glass.
You know the problem: light hits glass, partially reflects back instead of passing through. This not only costs brightness – it also creates ghosting and flares you don't need. This is where antireflection coating comes in. It's a thin, multi-layer coating on the lens surfaces that cancels out reflections through interference. The principle works like noise-canceling: out-of-phase waves cancel each other out. The result is higher light transmission – typically a 2–5% gain per air-to-glass surface – and less light scattering uncontrollably.
In practice, you'll notice this immediately when shooting into light. Where an uncoated lens creates ghosting and a diffuse veil, a good antireflection coating delivers a clean image with punch. Especially when shooting against the light, at night, or when working with high ISO values, the effective increase in brightness becomes noticeable – you need less light on set or one stop less in the edit. Premium lenses today have multi-layer coatings specifically optimized for certain wavelengths. Some manufacturers tint the lenses slightly yellowish or violet – this isn't aesthetics, but optical engineering. The tint shows you which spectral ranges are coated.
Important: Antireflection coating is not a panacea for lens flares. It reduces reflections and ghosting, but not intentional artistic flares that you deliberately create with an anamorphic lens or special techniques. If, on the other hand, you point a standard zoom with weak coating at the sun, you'll see the difference: a strong, diffuse glare instead of a clear image. In modern cine lenses, the antireflection coating is so well optimized that you hardly notice it during normal shooting – that's the sign it's working.
In the edit, antireflection coating also plays a role when you combine footage shot with different lenses. Old and new lenses have different reflection characteristics. If you have to match-cut a vintage lens without modern coating next to a contemporary premium zoom, the differing image quality can be distracting – especially with high contrast or backlight. That's why it's worth opting for consistently well-coated lenses when renting – and why many cinematographers forgo single-coated or uncoated vintage glass when they need modern sensitivity and cleanness.