Hoya 55mm W2 Umber Warming

Hoya 55mm W2 Umber Warming

The Hoya W2 Umber Warming filter prevents a blue cast and adds a warm glow to your photos. This type of filter is ideal for shooting portraits, adding warmth to pale skin tones.

Hoya's Umber Warming series includes the W2, W4, W10, and W12 versions. These provide a mired shift of +20, +40, +100, and +120 respectively. The higher the mired shift, the more warmth is added. Because differences in colour temperature (Kelvin) are not linear, this is expressed as a mired shift — an abbreviation of 'micro reciprocal degrees Kelvin'. The formula is as follows: mired (numerical value) = 1,000,000 / colour temperature. To illustrate with an example using a colour temperature of 6500K: 1,000,000 / 6,500 = 153.8. If the desired colour temperature is 5500K, you also need to calculate its numerical value: 1,000,000 / 5,500 = 182. The difference to bridge — in other words, the mired shift you want to achieve — is +28.2. With this knowledge, you can choose the right filter.