Could you translate "Ist das echt?" like "Are you serious?" ?
(Idiomatic translation, not literal)
According to my dictionary, im Ernst, ernsthaft and allen Ernstes are used in this manner. No mention of echt.
When I saw this I thought "for real?" Very much the same meaning as "are you serious?"
I think there is a mistake in the answers please check it out: is is real? is the answer to ist das echt.