Lenses ideally project the color spectrum right on the sensor, creating a sharp image. But in reality, there are several colors in the spectrum that aren’t precisely projected, especially in low quality lenses. In cases like these, the focus falls outside the intended focus point, sometimes in front and sometimes behind the sensor. This means that it spreads or disperses (not focused on one point). Because it doesn’t fall on one exact point, chromatic aberration is resulted in the photographs produced. Characteristics of a chromatic aberration is the visibility of odd colors on the edges of the objects in the photo, usually in the color of purple, blue, green, or red.
High quality lenses (like Canon’s L Series or Nikon’s ED Lenses) uses optic materials that have super low dispersion, minimizing the spreading of colors.
A few tricks to lessen Chromatic Aberration are:
1.Decrease your aperture. If chromatic aberration is quite apparent in f/1.4, try a smaller aperture such as f/2.8.
2.Avoid zooming fully with your lens. If you’re using telephoto lens of 70-300 mm, avoid zooming to 300 mm unless absolutely necessary. Photographing at a focal length of 200mm will reduce CA.
3.Avoid High-Contrast situations. If you’re lens does have high chromatic aberration, try avoiding situations like backlighting.
4.Be cautious when using super zoom lenses. Super zoom lenses have many advantages like when used in traveling, but if your priority is to avoid CA, then use another lens. Super zoom lenses (like the 18-200 mm) usually has a fairly severe CA at its wide focal lengths.
5.Pay close attention to the cleanliness of your lens. A dirty lens surface or a moldy lens will trigger the emergence of chromatic aberration.