Why couldn't I go faster than 1/250?

Does this basically mean that when outdoors shooting with flash in bright sunlight. If your shutter speed start to go above 1/250 then HSS should be switched on? And secondly at what shutter speed if that's true does HSS start failing (i.e. not being quick enough?) I guess HSS also sucks batteries?

Mint_Sauce wrote in post #5741067
Does this basically mean that when outdoors shooting with flash in bright sunlight. If your shutter speed start to go above 1/250 then HSS should be switched on? And secondly at what shutter speed if that's true does HSS start failing (i.e. not being quick enough?) I guess HSS also sucks batteries?

It doesn't fail. It has progressively less range. See the flash manual under "High-speed Sync".

basroil wrote in post #5739619
i didn't mean that your thing was wrong, it's perfectly accurate. however, sync speeds aren't going to get much better, as rene said

sync speed is sync speed regardless of how it's done isn't it

P&S cameras can have ridiculous sync speeds due to that. though few manufacturers actually take advantage of that..

edit:

you mean 3 million meters/s in vacuum, slower in the atmosphere (in the center of the sun going outwards, fractions of an inch a second)

It is actually 299,729,458 meters/s, or about three hundred million meters per second.
According to my understanding, here is how the flash works. Any flash can only be turned on and off with in a certain period of time. You can not do too quickly, nor can you do it too slowly. If the flash is set to full power, it will stay lit to this fixed time (set by the manufacturer?? if it stay lit longer, it might burn out???). If the flash is set to less power, then it does not stay lit as long.
In the case of high speed sync, the shutter opens and close way too fast for the proper exposure of the flash (according to the camera's calculation/ or the flash is not capable of that fast??? I'm not sure). If the flash is set to turn on and then off to synchronize with the shutter, the amount of light being shined on the subject is going to be less. But if you leave the flash on long enough for proper exposure, part of the picture will be dark as when the second curtain closes, the flash is still on. Therefore, this has not thing to do with the speed of light, but more to the time it takes for the proper amount of light to be shined on the subject.

True it is a 'proper exposure" problem. But the problem is the second shutter starts to close before the first one is all the way open. So a single flash will never reach all of the sensor. High speed sync causes the flash to fire a lot of times, but to the eye it still looks like one flash, to cover the sensor completely.

Precisely. And as then a shorter shutter speed means a narrower slit, moving across the sensor, the flash has to emit more pulses in the burst. That's why the range decreases as the shutter speed becomes shorter.