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Rob Burnside's picture

Using flash to stop the subject.

Posting an example of what I don’t want. I know the flash is supposed to “freeze” the subject in frame to eliminate motion blur. This photo was taken with a tokina 11-16mm at 1/250th and a cheap speedlite attached to the hot shoe. I’m not happy with the motion blur on the subject. Everything else I’m happy with. Let’s discuss!

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4 Comments

Hey Rob, this was obviously posted a bout a year ago but maybe I could help if you haven't already figured it out. What you want to look into is flash duration. That's the length of time from the second the flash starts to fire to when the flash completely stops. I'm going to assume that this flash was on full power because it's so bright out. At full power that's when your flash will be the slowest. Usually for bmx you'll want your shutter speed to be at least 1/1000th of a sec to freeze the action. that means that you'll also want your flash duration to be 1/1000th. usually cheap speedlites with have a flash duration of around 1/200th at full blast. You'll have to power down to get that faster. There are a few flashes that can do 1/1000th at full power like the vivitar 285hv(a personal favorite of mine) but there are many more that are diffidently better quality though more expensive. Hope this helps ya out!

Thank you for the reply! I did not realize cheap speedlites were that slow of a duration. I knew they were slower, but not 1/200th. I guess I need to start reading the flash durations on lights. I’ve used my godox ad600 to achieve no motion blur, but I’ve also used HSS to achieve that. The AD600 is powerful enough to use HSS in mid day. Once again thank you for the info!

Anytime! Yeah they're pretty slow. Also there two different measurements for duration. t.1 and t.5 I've found that you want to look at the t.1 if available. if not specified then assume it's t.5.
a t.5 rating of 1/4000th seems really fast but it's equal to 1/300th in a t.1 reading. I've found that the t.1 reading is closer to what you would think of with a shutter speed.
so a t.1 rating of 1/1000th is correct the stop action but a 1/1000th t.5 will not stop action because it's equal to something around 1/75th. you would never see a flash quite that slow these days but as an example it works.
hhs is a good way to go also but some speedlites and a pw setup is so compact and can be pretty inexpensive if you get the right stuff

I do think godox stays with the t.1 reading for all of their products