Flare, and Hotspot in IR Photography
How to get rid of it
No, it is the flare!
Huntington Library, Los Angeles
Nikon D90, AFs 14-24, @ 14 mm, f 11, 1/90 s
It is not the Hollywood "meteor hit your backyard movie" come true. And I did not drop my D90 to take cover,either. Because I did not even notice the bright spot coming to the left of the image until I took a look at the LCD.
It is the infared flare. When there is direct sun light shine on the front element, there might be flare, more or less. In this case, even the newest wide angle lens with "nano" coating from Nikon, the monster AFs 14-24, did not do well.
How to avoid the pesty flares? Simply, please try to shield the front glass from the sun. Use the lens hood, your hand, your cap. If you have to shoot in to the sun, remove the filters. (Caution: do not stare at the sun--it will cause damage to your eyes!)
Arch of the White City
Arequipa, Peru
Canon XT, EFs 10-22 mm @ 10 mm
Or, you can use an interesting object, such as tree trunk,to shield the lens from the sun. I like to shoot through a tree, and make it "tranparent" in IR. In color photography, especially when sun is low, I like to use a object to just block the sun, so that I get all the golden color, but without a white fireball to blow the images.
Hot Spot
Dunes at Stovepipe Wells, Death Valley N.P.
Canon Digital Rebel, EFs 18-55 mm kit lens
Some lenses, due to their coating, may cause a bright spot in the center of the images, aka, hot spot. This happens only under certain conditions, with very few lenses (the other one that I used is Tokina AT-x 12-24mm). The above image is a extreme case. Most of the time, it is the flare that ruin the images. Please remember to shade the lens, and look at the LCD after you take the images. Any flare, or you hat, in it?