Today’s Question: I realize there are tools for removing chromatic aberrations from a photo, but is there anything I can do to avoid chromatic aberrations in the first place?
Tim’s Quick Answer: Chromatic aberrations are caused primarily by issues with the lens being used to capture a given image. Therefore, the best way to avoid chromatic aberrations in your photos is to use lenses of the highest quality possible, and to favor lenses with longer focal lengths over wide-angle lenses.
More Detail: Of course, avoiding wide-angle lenses altogether isn’t really a great solution, since this approach can have a significant negative effect on the types of images you’re able to capture. So instead I recommend trying to ensure you are purchasing lenses of the highest quality possible. In the context of chromatic aberrations, this is of particular concern with wide-angle lenses.
Chromatic aberrations are caused by a variety of factors, but in general you can think of these colored halos along contrast edges as being caused by certain wavelengths of light being out of focus relative to the majority of wavelengths represented in the scene. Wide-angle lenses represent a particular challenge, since these lenses are “bending” the light from the scene more significantly in order to project that light onto the image sensor in the camera.
Higher quality lenses will do a better job of redirection the light from the scene, helping to reduce the risk of chromatic aberrations. In general you don’t need to worry as much about chromatic aberrations with lenses of relatively long focal lengths. But when it comes to wide-angle lenses, spending more for a higher quality lens can make a big difference in terms of overall image quality, including helping to reduce the risk of chromatic aberrations.
High contrast edges are the most likely areas to find chromatic aberrations, so avoiding such scenes would help you avoid chromatic aberrations. But again, I don’t think it makes sense to avoid photographing certain scenes or avoid using wide-angle lenses just to reduce the risk of chromatic aberrations in the first place.
Of course, as noted in the question, there are tools for removing chromatic aberrations in your photos, and they actually work quite well. That doesn’t mean that I would suggest purchasing a lens of inferior quality. But if a more expensive lens doesn’t make sense for you (and if you don’t want to stop photographing with wide-angle lenses), there are ways to significantly mitigate the appearance of chromatic aberrations in your images.