Flare is particularly caused by a very bright light sources either in the image or shining into the lens but not in the image. Most commonly, this occurs when shooting into the sun (when the sun is in frame or the lens is pointed in the direction of the sun).
Here are some interesting analogue photographs of flare that were shot by toy cameras.
|Birds - Baltimore, 2007_Tru-View by hookstrapped|
|twin suns on the cold plastic holga planet by whickus|
|London bound by slimmer_jimmer|
|ulysses by +faster+|
|Gerrard St. by -ciaran|
|Paris flare steps by 25ThC|
|Summertime by Chasing Monoeides|
|Beware the Flare by bertwootton|
|Chopper by harragan|
|Untitled by benman31|
|ave 26. venice beach, ca. 2012. by eyetwist|
|Sweigalp backlight. by Markus Moning|
|sun, flare and gates by pho-Tony|
|Intimate Dawn by Hayden_Williams|