How to avoid blooming :: Digital Photo Secrets

How to avoid blooming

by David Peterson 11 comments

Your mother told you never to look at the sun, or you’ll go blind. Whenever some cameras take a picture of a very bright object (like the sun), the light can get so intense that it doesn’t just affect one part of the image. The light streaks out from the light source and creates a supernova like effect that can consume a significant frame. It’s called “blooming,” and in this article, I’ll show you how to stop it.

What causes blooming?

Before I can explain the causes of blooming, you need to know a few things about the way your camera’s image sensor works. An image sensor, or CCD, is an array of photovoltaic cells that convert light into an electrical charge. Each pixel has one of these cells, and when it receives light, that light is converted into an electrical charge. The charge is then converted to a number and stored as an image file on your camera.

If one pixel receives more light, it generates a bigger charge and it gets recorded as being “more bright” than another pixel. CCDs also take information on the wavelength of light to figure out its color. This too, is ultimately converted into a number and stored as an image file.

Blooming happens when a large amount light gets focused to a single point on your camera’s image sensor. This can create so much charge that it actually bleeds from pixel to pixel until it eventually spreads out. Whenever blooming occurs, it has a pretty well-defined boundary. This stands in contrast to lens flares, which can give the entire frame a strange tint.

Most blooming looks like a giant blob of white with pixelated edges. In some cases, light from different wavelengths (blue light or violet light for example) can get so intense that it does the same thing, creating a giant blob of colored light with pixelated edges. The classic case with colored light happens when you point your camera at a colored strobe. The flash is so intense that it causes a colored kind of blooming.

With white light, it usually happens when you point your camera directly at the sun (didn’t your mom tell you not to do this?). The light focuses at a single point on your image sensor, creating a huge charge that bleeds onto the neighboring pixels. You’ll know you’re experiencing blooming when the sun doesn’t even look like the sun. It will look like a pixelated mess, something akin to a phaser blast straight out of Star Wars.

How can you prevent blooming?

For one, listen to your mother. She’s right about a lot of things. Don’t put the sun in the shot. Keep it to the side, and while you’re at it, put a hood on your lens (I swear you’d leave the house naked if someone didn't tell you not to). It will keep stray light from entering your lens and causing a flare, which under certain circumstances can also cause blooming. Think of what happens when the sun reflects off of the chrome on a car, and this should make sense.

There are certain times of day when it’s okay to point your camera at the sun. Mornings and sunsets happen to be one of them. At these times, the light isn’t nearly as intense. It’s also a lot more pretty. But even then, you don’t usually want to point your camera right at the sun. You’d only want to do that if the sun were obscured behind some clouds, turning them bright orange or pink.

Always be careful when you’re thinking about incorporating the sun into your pictures. Looking at the sun through the viewfinder will make you go blind.

You can also increase your camera’s shutter speed to block out some of the light, but this isn’t always effective. Only certain camera makes and models will allow you to do this. Those of you who own digital SLRs, pay heed. Yes, your camera says it can achieve shutter speeds as high as 1/4000 sec, but chances are that it doesn’t do this by using a physical shutter that shuts faster (thus blocking the light). It’s done by modifying the image file after it’s taken. This, while clever, does nothing to stop blooming from happening.

Keep your camera away from the sun; or looking at bright lights; use high shutter speeds, and your blooming problems should be a thing of the past. And if you’re still having issues, leave me a comment below. I’ll help you sort it out.

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Comments

  1. Jaap says:

    Great article. Faced this problem with my new Irix 15mm lens and Irix told me it's blooming. Thanks for sharing tips to avoid the problems. One tip from me to avoid blindness: use your lcd screen when photographing the sun, instead of the optical viewfinder.

  2. Phillip Kuhne says:

    David, ---do you think at 64 i am too old to start doing photography seriously.
    i mean to do it as a profession.
    i love doing it though currently only do it for the love of it.-[ as an ametuer].
    would appreciate a reply from you on this preferably A S AP.
    REGARDS pHILL kUHNE.

  3. Ronald Berman says:

    The following issue I haven't seen discussed much, but I've observed that I have to be careful when looking through the camera at the full moon, on a clear night. With my superzoom camera telescoped to 600mm, the light is quite bright and after looking and photographing the moon for too long a period of time, I've had some temporary visual loss. So I'm much more careful now not to overdo it. After all, the moon is a mirror reflecting the sun't rays, so it makes sense that the light reflected from the moon can be very intense, especially when magnified by a telescope or zoomed out camera lens.

    I think people should be cautioned when using telescopes and telescopic camera lenses to use caution when looking the the bright, full moon. We all know that the sun is dangerous to look at, but little is written about the danger of looking at the full moon for too long a period of time.

    • Ann says:

      Ronald, maybe it's just all the dark after the light.

    • David Peterson says:

      Hi Ronald,

      I wouldn't worry about your eyes when looking at the moon (even zoomed in). It's just reflected light from the Sun, and we look at that all day every day! When we see houses, trees, fences, it's all using reflected light from the sun.

      David.

  4. Honey Sharp says:

    What I've been wondering about for years is why the brilliant colors of a sunset are not always captured by my camera. They're often flat. Of course, I know how to change that later but still...

  5. John Foster says:

    As a Realtor I often have to take pictures of rooms where a lot of sunlight comes in through the windows which causes a great white ball which prevents you from seeing what is outside the window.
    How do I prevent this.
    It is not always possible to shoot at night to avoid this

  6. Tim M says:

    Thanks for an informative article. I am teaching a class about blooming and this was a great resource.

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