D300 - x320 shutter speed?

[welly]

I just found this and I'm not entirely sure what it's for. Can anyone enlighten me?

 

[puddleduck]

Yes, it for flash sync, the manual explains, have a look at Auto FP mode.

 

[welly]

Oh cool, I'll do that. Thanks!

 

[puddleduck]

The usually sync limit is 1/250, this extends it a tad, at the cost of some flash power.

Unless you shoot outdoors with fill flash you'll likely never need to worry about it.

D300 default is 1/250 Auto FP.