We are often told to be careful of ghosting and flaring when shooting in backlight, or in other conditions with a strong light source in the frame. But what exactly is ghosting and flaring, and how do we prevent them? Let's find out in this article. (Reported by Shirou Hagihara, Digital Camera Magazine)

 

What causes ghosting and flaring?

Flaring, also known as "veiling flare", occurs when light reflects off the lens, or other elements such as the lens barrel and mirror box, making part or all of an image appear soft or hazy.

Ghosting, also known as "ghosting flare", is caused by a strong light source being reflected repeatedly. It appears as a clear artefact that is usually located symmetrically opposite to the light source.

Some factors that influence flare and ghosting

- Number of lens elements: The more lens elements, the more things there are inside the lens that can reflect light.

- Focal length: A shorter focal length makes the light source appears smaller, which can make ghosting and flaring less visible.

- Anti-reflective coatings: Some lenses, such as those from Canon's L series, have special anti-reflective coatings that help to reduce flaring and ghosting.

Tip: On Canon lenses, look out for coatings such as Air Sphere Coating (ASC) and Subwavelength Structure Coating (SWC). Note that even with these coatings, it is difficult to completely eliminate ghosting and flaring. 

- Dust and dirt: Dust accumulating inside the lens, as well as dirt and smudges on the front lens element or UV filter can all cause additional light reflection, contributing to ghosting and flaring.

 

Examples of ghosting and flaring

Flaring

Ghosting

Know this: Ghosting and flaring is not always bad!

In general, ghosting and flaring are considered to degrade image quality. But if it is not necessary for your images to be absolutely clean and clear, you can also deliberately incorporate them into your images as an artistic effect.

Photographer tsukao loves creating lens flare with the EF50mm f/1.4 USM. Find out more here.

 

How do I prevent unwanted ghosting and flaring?

Use a lens hood

It's the very least that a photographer should do to address these effects. 

(from left to right) EW-63C / ET-63

Each lens hood is shaped differently to match the characteristics of different lenses, so make sure you get the right one for your lens. For example, the EW-63C lens hood is compatible with the EF-S18-55mm f/4-5.6 IS STM standard zoom lens, while the ET-63 lens hood is compatible with the EF-S55-250mm f/4-5.6 IS STM. 

Also read: 3 Reasons Why You Should Start Using a Lens Hood

Use something to block out excess light

In a pinch, you can also cut out flare-inducing light using objects such as your hand, a hat, or a board-shaped object.

 

If all else fails, fix it in post-processing

It's hard to completely eliminate ghosting and flaring. If you have done everything you can to prevent them but they are still visible in your images,  you will have to fix them in post-processing. Warning: It can be a painful, time-consuming process!

If the ghosting and flaring area is not too big, you can use the cloning, brush or spot removal tools in your favourite post-processing software to correct the image.

If you shoot in DPRAW format, you can use the Ghosting Reduction feature in the DPRAW Optimizer, available in Digital Photo Professional version 4.5.0 and above. 

 

Now that you know how to handle ghosting and flaring, check out these lovely backlit images and learn how they were achieved:
How I Nailed this Shot: Adding Impact to a Grand Forest Landscape
4 Steps to Capture a Soft, Dreamy-looking Backlit Portrait
Decisions in Landscape Photography: Whether or Not to Include the Sun in the Frame

 

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