Author Topic: Flash: auto-switch from hss to 2nd curtain sync  (Read 7032 times)

Marsu42

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Flash: auto-switch from hss to 2nd curtain sync
« on: April 04, 2013, 06:42:44 AM »
This is a major annoyance on Canon flashes, but it could be fixed by software. There is a Canon "sync" menu option and an equivalent button on the flash that cycles though 3 settings: a) 1st curtain sync, b) high speed sync, c) 2nd curtain sync.

The problem: If you enable hss it's only about shutter speed faster than x-sync (5d & Rebels: 1/200s, 7d/60d: 1/250s, 6d: 1/180s). For x-sync speeds the camera auto-switches to 1st curtain sync when hss is enabled, meaning that auto-switching to the very useful 2nd curtain sync is not possible because it is limited to x-sync and everything brighter will be overexposed.

Request: An option "auto-switch hss & 2nd cs", the camera should use 2nd cs when <x-sync and hss when >x-sync. Implementation: Ml would have to check if flash is enabled, and set one or the other in the Canon props.

1%

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Re: Flash: auto-switch from hss to 2nd curtain sync
« Reply #1 on: April 04, 2013, 07:10:28 AM »
All that is on the way. I can't even enable HSS on my YN468... Stuck on that 1/180.. So far expo override didn't help.

Francis

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Re: Flash: auto-switch from hss to 2nd curtain sync
« Reply #2 on: April 04, 2013, 07:14:23 AM »
What would be the use of 2nd curtain on HSS, if you aren't dragging the shutter? If you are faster than 1/500s or so there is almost no difference in the timing between the 2 curtains. Also starting the HSS "pulse" on the 2nd curtain is going to limit your output even more than happens with HSS.

I'm just curious what sort of situation you have in mind.

Francis

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Re: Flash: auto-switch from hss to 2nd curtain sync
« Reply #3 on: April 04, 2013, 07:15:32 AM »
All that is on the way. I can't even enable HSS on my YN468... Stuck on that 1/180.. So far expo override didn't help.

I didn't think the 468 had HSS. At least mine from a couple of years ago doesn't.

Marsu42

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Re: Flash: auto-switch from hss to 2nd curtain sync
« Reply #4 on: April 04, 2013, 07:48:41 AM »
What would be the use of 2nd curtain on HSS, if you aren't dragging the shutter? If you are faster than 1/500s or so there is almost no difference in the timing between the 2 curtains. Also starting the HSS "pulse" on the 2nd curtain is going to limit your output even more than happens with HSS.

Ok, again....

* I know there is no 2nd curtain sync on hss, it's mutually exclusive, hss is continuous lighting and doesn't "sync" at all

* I failed (second language and so on) to convey what I want: I'd like the camera to automatically switch to 2nd curtain sync *below* x-sync speeds and auto-switch to hss if faster. Currently there is only the option to *either* use 2nd curtain sync *or* auto-switch fomr 1st curtain sync to hss, not from 2nd curtain sync. Clearer?

a1ex

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Re: Flash: auto-switch from hss to 2nd curtain sync
« Reply #5 on: April 04, 2013, 10:35:36 AM »
Scrax did some nice research in this area, you can take a look here: http://www.magiclantern.fm/forum/index.php?topic=3920.0

Marsu42

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Re: Flash: auto-switch from hss to 2nd curtain sync
« Reply #6 on: April 04, 2013, 08:09:17 PM »
Scrax did some nice research in this area, you can take a look here: http://www.magiclantern.fm/forum/index.php?topic=3920.0

Thanks for the link, that's certainly conclusive (though it doesn't include the new props for the rt flashes like group mode) - I'll asking around in the thread you stated.