What is Chromatic Deviation?
Chromatic aberration is an optical phenomenon in which correct images cannot be produced because the camera lens is unable to focus the wide range of wavelengths of light on the same plane. In other words, the colors are broken / bent incorrectly by the camera lens, resulting in a mismatch in focus, causing the colors to not work as they should. This often results in a border or halo around objects. Chromatic aberration is particularly used in ophthalmology where it is used in the duochrome eye test to ensure that the correct power of the lens is being used by the patient.
Chromatic aberration is also known as chromatic distortion, spherochromatism, color fringing or purple color fringing.
Chromatic aberrations usually propagate in high-contrast scenes and when shooting large apertures. Chromatic aberration is controlled more or less in the center of the frame. However, it is not the same for image corners. The distribution of the glass used determines the amount of chromatic aberration. There are two main categories of chromatic aberration, namely axial chromatic aberration and lateral chromatic aberration. When different wavelengths of light are focused by the lens at different distances, an axial aberration occurs. Lateral aberration occurs because different wavelengths are focused at different positions in the focal plane. In addition to color photography, chromatic aberration can also affect black and white photography, where chromatic aberration leads to blurry images.
When shooting in RAW, the chromatic aberration can be effectively eliminated in post-processing. To correct for chromatic aberration, lens manufacturers often use achromatic lens designs. This construction uses a second lens with a different dispersion than the main lens to correct for the chromatic aberrations the light beam experiences as it passes through the first lens. Certain third-party tools are also capable of minimizing chromatic aberration. In black and white photos, the chromatic aberration is minimized with the help of a narrow-band color filter.