Episode 149: Lens Flares Ahead!

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Every time you have a bright light shining into your lens you get a lens flare. This can look nice or horrible. You can avoid much of it with a lens hood – and with paying more money for better coated lenses.

But when you have these nasty spots on the image – there are ways in GIMP to heal them. Some are discussed in the forum thread where I also got the image for this show.

My preferred way to tackle a problem is to understand the source of it. Solving the problem is often much easier then. (This is the theory, often I just poke around…..;-) ) So I start with a bit of blackboard – showing that a lens flare is only added light, the original image lies below and the flare can be (in theory) subtracted from it.

In GIMP I do this with comparing similar colours in and outside of the flare. A bit of layer magic and the flare is gone. Except for the fringe where my patience ran out.

The TOC

00:20 Greetings, Flattr
01:45 Lens flares
02:20 Origin of lens flares
12:10 Avoid lens flare with a lens hood and lens coating
13:05 “Digital” lenses
14:20 Solution: subtract light
16:00 Curves to correct the contrast
19:45 Subtracting light from the flare
19:45 How much light was added in the flare?
22:00 Sample points
23:05 Docking a dialogue
23:30 Mixing the correction colour
27:25 Correcting the second flare
33:00 Recap
35:15 A quick crop
36:30 Why layers?

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Meet the GIMP Video Podcast by Rolf Steinort and Philippe Demartin is licensed under a Creative Commons Attribution-Share Alike 3.0 Germany License.
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7 thoughts on “Episode 149: Lens Flares Ahead!

  1. I usually kill shots with lens flare right in camera and retake them to save work later on (yes, I’m lazy). But I found some that survived and will try to mend them.

  2. Do you have way to auto-detect the lens flares? It will be quicker for filter out images needing to be fixed. Can it be prevented with small camera? It has no hood at the front.

  3. Great approach! This method would have never come to my mind.
    Now we know another standard application for a further layer mode.
    Anyway I like your board-and-chalk shows! :-)
    Thank you.

  4. @solothum: to prevent flare using a small camera without a hood, I will often shoot one handed and use the other hand to shade the lens. Since the flare is caused by direct light on the front lens surface, anything that casts a shadow on the lens will work, like your hat, your spouse, a ham sandwich . . . the possibilities are endless!

    Actually, in many shooting situations, like the picture in the video, stepping one foot to the side may have put the lens in the shadow of one of the trees.

  5. Yes, keeping the lens in the shadow solves most of the problems – except for direct sources in the field of view.

    At film sets in the sun one can see an assistant with an umbrella or a black plate on a stick, casting a shadow on the lens. No idea how he is named in the credits. ;-) And they use elaborate lens hoods.

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Anything to add from your side of the computer?