Sekonic Meters & Canon Speedlite HSS - compatible?

m.shalaby wrote in post #12433017
Gotcha. Thanks. Do you know the off the top of your head the max speed for the L308S ?

c'mon man try something

I do happen to know the max shutter speed for the L-308S but getting that information was as easy as going to the Sekonic site, to Products, to the L-308S, and then to specs. It was right there.

The L-308S has a maximum shutter speed (shutter sync speed for measuring flash) of 1/500s, which is fine.

Numbers can vary a bit but as mentioned twice already.....

Once you exceed your camera's max shutter sync speed you start to lose light. My testing (and others that have done similar tests) shows that going 1 stop beyond the max shutter sync speed you lose between 2 and 3 stops. My tests showed a loss of -2.7EV.

Increasing the shutter speed beyond that will lose about another stop of light per full stop (I measured -.9EV) of shutter speed.


If you're max sync speed is 1/250s and you push that to 1/500s then you've lost -2.7EV. Increase shutter speed by another stop and you lose another -.9EV and will continue to lose another -.9EV for each stop of shutter speed.

If we forget about ISO in this example and just look at shutter speed and aperture it's simple to calculate. Let's say you're shooting at f/8 and 1/250s and 1/250s is your max shutter sync speed. Increasing the shutter speed to 1/500s (1 full stop) reduces output by ~3EV, which means you're now shooting at f/2.8 and 1/500s. Increase the shutter speed by another full stop to 1/1000s loses another -1EV, and now you're shooting at f/2 and 1/1000s.

yogestee wrote in post #12433081
I just did a quick test.. 50D with 430EX II hotshoe mounted at 1000th second, flash on HSS and in manual.. Yes my L-358 did take an accurate flash meter reading (at 1 metre)..

See. I did not tell a lie

Robert - I wish that strobist site mention these kind of things. Maybe you and dave should rent a van and do a tour.

BTW - What I and another posted found that just going in HSS mode at max Sync speed will make you loose 2 & 1/2 to almost 3 stops. So if you are at 1/250 and then engage HSS mode on your flash, but still keep 1/250 your flash output will drop a little over 2 & 1/2 stops. Then after that you get approx 1 stop drop for every stop increase in ss.

Now when using mini/flex/ac3 (like OP) you can play with ss where the crossover from HyperSync to HSS happens. For example on my 1dmk2 I can make HSS happen at 1/640 instead of 1/250. On my 5d, I can only manage 1/250-1/320.

FJ LOVE wrote in post #12433104
c'mon man try something

I'm at work right now, lol... I cant!

bobbyz wrote in post #12433288
Robert - I wish that strobist site mention these kind of things. Maybe you and dave should rent a van and do a tour.

This is way too technical for the Strobist site. Hobby likes to keep things super simple and considers those of us that use hand held light meters to be uncreative and anal.

yogestee wrote in post #12433081
I just did a quick test.. 50D with 430EX II hotshoe mounted at 1000th second, flash on HSS and in manual.. Yes my L-358 did take an accurate flash meter reading (at 1 metre)..

This makes sense - HSS is just pulses at a set brightness, right? As long as the brightness/strength of the light doesn't change and the meter doesn't get confused with any sort of pre-flash and you're within the meter's SS range, it should work, right?

Hmm...

TheBurningCrown wrote in post #12436931
This makes sense - HSS is just pulses at a set brightness, right? As long as the brightness/strength of the light doesn't change and the meter doesn't get confused with any sort of pre-flash and you're within the meter's SS range, it should work, right?

Hmm...

Correct. The short amount of time in between pulses isn't enough for the meter to think it's no longer seeing the flash.

I think since you set the ss on the meter, the meter is looking at flashes during all that time so if one big flash vs series of smaller flashes it doesn't matter.

bobbyz wrote in post #12433301
BTW - What I and another posted found that just going in HSS mode at max Sync speed will make you loose 2 & 1/2 to almost 3 stops. So if you are at 1/250 and then engage HSS mode on your flash, but still keep 1/250 your flash output will drop a little over 2 & 1/2 stops. Then after that you get approx 1 stop drop for every stop increase in ss.

Now when using mini/flex/ac3 (like OP) you can play with ss where the crossover from HyperSync to HSS happens. For example on my 1dmk2 I can make HSS happen at 1/640 instead of 1/250. On my 5d, I can only manage 1/250-1/320.

Actually, in this thread https://photography-on-the.net …p?p=11830711#po​st11830711 we determined that the actual behavior of flash GN while flash is in HSS seems to vary with camera model and/or flash unit!

40D + Metz 54MZ combo and confirmed with flash in both ETTL and manual with HSS Off/On; the flash max distance reports 23' in both HSS on/off at 1/250, and this flash output drops to 7.3' when at 1/320 or ABOVE max X-synch speed, and (The camera was in Manual mode and HSS On.) A similar behavior regardless of metering mode of the camera, does NOT alter behavior of the flash output

With my 5D at 1/200, max distance at f/4 is 13' with HSS On (for the FL coverage and ISO chosen), and 37' with HSS Off, which is a loss of -3EV simply by turning on HSS at the max X-synch speed of the 5D. If I change the shutter speed to 1/160, I get the same max distance for HSS On/Off.


Moderator and myself and others verified that the behavior of HSS seems to be camera model dependent as well as flash dependent...YMMV
Some flash units exhibity more loss of power (as much as -4EV) and some less (as little as -2.7EV) going to one full EV shutter speed higher than X-sync speed. And some cameras had to be set at least 0.33EV above X-synch to see initial flash power loss in HSS, while others showed that power loss simply with HSS on while at X-synch speed.

well, at least i know i bring up good topics for discussion

m.shalaby wrote in post #12440979
well, at least i know i bring up good topics for discussion

It's always good to know this stuff, never know when you'll need
Image deleted, I realized I didn't need HSS.

Beautiful, Ralph.

TMR Design wrote in post #12441101
Beautiful, Ralph.

Thanks Rob

I just realized I didn't need HSS for the series, I was using it a few minutes earlier.

I'll repost anyway so as not to confuse.

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