blitzen
to flash
To emit a short, bright light, as happens during a thunderstorm.
Es donnerte laut und am Himmel begann es zu blitzen.
There was loud thunder, and lightning began to flash in the sky.

to flash
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to flash
To emit a short, bright light, as happens during a thunderstorm.
Es donnerte laut und am Himmel begann es zu blitzen.
There was loud thunder, and lightning began to flash in the sky.

The verb 'blitzen' (to flash) is derived from the noun 'der Blitz' (lightning/flash). All meanings describe a very short, bright flash of light or a quick sparkle.
Der laute Donner folgte direkt auf den hellen Blitz.
The loud thunder followed directly after the bright flash of lightning.
When referring to a thunderstorm, 'blitzen' (to flash) is almost always used with 'es' (it) as an impersonal subject. It often appears together with 'donnern' (to thunder).
Schau mal, draußen blitzt und donnert es.
Look, there’s lightning and thunder outside.
In connection with a speed camera, the passive construction 'geblitzt werden' (to be flashed) is usually used. The subject is the person who was driving too fast.
Er ist gestern auf der Autobahn mit 140 km/h geblitzt worden.
He was flashed yesterday on the autobahn doing 140 km/h.
When you use a flash unit while taking photos, you use the verb actively. You, as the photographer, are the subject of the sentence.
In diesem Museum darf man nicht blitzen.
You are not allowed to use a flash in this museum.
'Blitzen' (to shine/sparkle) can also be used figuratively for strong shining or gleaming. It is often used to describe extreme cleanliness or an intense expression in the eyes.
Nach dem Frühjahrsputz blitzte das ganze Haus.
After the spring cleaning, the whole house shone.
to catch
'erwischen' and 'blitzen' can seem similar in traffic when someone is driving too fast and is checked. In this context, 'blitzen' is very specific: a speed camera photographs a vehicle because it is going too fast. 'erwischen' is more general. It means that someone is caught or apprehended doing something forbidden. So you can say that the police 'erwischt' someone. 'Geblitzt werden', however, specifically means being checked by a camera. The risk of confusion arises because both words can occur in the same traffic situation.

Auf der Landstraße wurde Lena gestern geblitzt.
Lena was caught by a speed camera on the country road yesterday.
Die Polizei erwischte den Fahrer, als er bei Rot über die Ampel fuhr.
The police caught the driver as he drove through the red light.