deaw wrote:thanks for the help so your basicly saying there is no great advantage of a sb600 or sb800 compared to the onboard flash. Is that correct
Not at all. Nothing could be further from the truth.
Your first question - from what I could discern - simply asked about the nomenclature - speedlight vs built-in flash. In those terms, there is no difference.
But when you're comparing specific units - as you are now - you're asking a whole different question. And specific units might be, for instance, an SB600, and SB800, a Metz 60CT-Whatever .... or the onboard flash on your D50.
They all might correctly be referred to as either a speedlight, or a flash, but in terms of specifics, you're comparing a Vespa to a V6 Holden.
The 600 and 800 both have a whole lot more power than your onboard unit, and they also offer the advantage of being used off your camera.