If you’ve ever taken your camera in for repair only to be told that nothing was actually wrong, that the issue is just an artifact of technology, I’m sure you were just as puzzled as many people out there. While a complaint like this isn’t highly common, it isn’t all that unusual either. Blooming, also known as pixel overcharging, is one of the best examples many users mistake to be a defect, but unfortunately is simply a limitation of the current technology.
Have you ever seen those distracting straight white lines that go from the top to the bottom of your LCD screen (see example image to the left)? How about a hazy color tone (most commonly pink and blue) that looks like a beam of light (see example image below)? If you have, then you have experienced blooming. It is important to distinguish this digital artifact from actual problems that can, and should, be repaired. Rows of dead pixels and especially rows of hot pixels could be interpreted as blooming (or vice versa). If you do in fact have a row (or rows) of dead pixels, it would appear in every picture in exactly the same place. On the flip side, if you have a row (or rows) of hot pixels, it would show up in exactly the same place but not necessarily in every image; the brighter the scene the more prominent it would be. Blooming would come and go, be intermittent, and move all over the place.
If you haven’t already guessed by its alternate name, pixel overcharging, blooming occurs when the pixels in the sensor are overloaded with sensory information. The pixels become overloaded when they are overwhelmed with light. When one or more pixels experience this, neighboring pixels can become affected from a kind of spill-over causing a row (or rows) of pixels to overcharge resulting in the streaks/beams you see. If you’ve ever taken a picture of a mountain landscape with the sun within the frame (while balancing for the mountains), you could likely experience the blooming effect.
Some of you may be scratching your head trying to recall a time when you’ve experienced this. The reason for that is most digital still cameras either have a CCD sensor that is designed with “anti-blooming” technology or have a CMOS sensor which is inherently immune to blooming. However, if you use the video function on your digital camera often, you probably see it all the time because for video that “anti-blooming” technology is currently only capable of reducing the effect. Using an LCD to compose a photo is nearly identical to recording video so it also often shows up there as well but many don’t notice it because it doesn’t show up in their actual images.
When users encounter these types of effects and they don’t know what it is, it can be understandably worrisome. The best thing you can do is consult someone with the ability to vet your concerns (camera store, camera repair facility, friend who is your digital guru) before spending your time and money submitting it for repair.
title image source from the Faulkes Telescope Project http://www.faulkes-telescope.com