Trouble with HSS on 430 ex

[Lsrwtr84]

I have a 7d camera and 430 ex speed lite. On my last two shoots I had trouble in that my high speed sync would not stay activated after a while. It would shut itself off and the flash would not trigger as well as having the "H" disappear on the speed lite display panel even though I had not changed any settings on my flash or camera. I changed my batteries and that did not solve the problem. This problem did not occur until the last month. My flash is almost 2 years old. Any ideas on what is causing my problem? How do I have it checked out or would it still be considered under warranty if I could find my receipt?

[Mykolas]

Hi Lsrwtr84,

If you set a shutter speed on the camera that is within its normal sync speed range, high-speed sync is no longer active and you will not see the icon in the viewfinder.  This is because high-speed sync is no longer necessary.  This could very well explain why you are sometimes not seeing high-speed sync active anymore.

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