Hoya 55mm W4 Umber Warming

Hoya 55mm W4 Umber Warming

The Hoya W4 Umber Warming filter prevents blue casts and adds a warm glow to your photos. type filter is ideal when shooting portraits to add warmth to pale skin tones.

This Umber Warming series by Hoya features a W2, W4, W10 and W12 version. These give a mired shift of +20, +40, +100 and +120 respectively. The higher the mired shift, the more heat is added. Because differences in colour temperature (Kelvin) are not linear, this is expressed in mired shift, an abbreviation of 'micro reciprocal degrees Kelvin'. The formula is as follows: mired (numerical value) = 1,000,000 / colour temperature. In a calculation example with a colour temperature of 6500K, this means the following. 1.000.000 / 6.500 = 153,8. If the desired colour temperature is 5500K, you also need to calculate the numerical value for this. 1.000.000 / 5.500 = 182. The difference to be bridged, or the mired shift you want to achieve, is +28.2. With this knowledge, you choose the right filter.