RF622 & 2nd curtain flash

The answer could be that the camera will only switch to second-curtain at longer shutter speeds, like below 1/30sec. Even then, it doesn't get properly second-curtain until yet longer speeds still, like 1/4sec and more. Handbook p197.
 
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Rob, it's possible!

Canon enforces its rule that 2CS is available only in non-wireless mode. So go to your 5DIII's flash control menu and disable Wireless mode, "OFF". (Shown in bottom figure on p.13 of TOYUG.) Then you can select 2CS. The quick flash control menus on the 5DIII are great to use, compared to the 450D ones.

TOYUG

p.s. it's YN-622C, not RF...
 
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SeedyBee said:
Rob, it's possible!

Canon enforces its rule that 2CS is available only in non-wireless mode. So go to your 5DIII's flash control menu and disable Wireless mode, "OFF". (Shown in bottom figure on p.13 of TOYUG.) Then you can select 2CS. The quick flash control menus on the 5DIII are great to use, compared to the 450D ones.

TOYUG

p.s. it's YN-622C, not RF...
Click to expand...

Clive, do you know why the native Canon system cannot do remote second-curtain sync? Not even with the new 600EX-RF guns. If third-party manufacturers can do it, there cannot be any technical reason, so I've often wondered if there's some legal/patent restriction?
 
Hi, Richard. I've read several guesses, but nothing authoritative. My guess is that it is related to the problem of optically passing the Fire Now! instruction while the shutter has been open for a while. A radio device does not have that problem, of course.

A device in the camera's hotshoe can be instructed through the hardwired data pins.

This principle was included in the patents of 2002, which until recently determined the whole off-camera Canon system.
 
SeedyBee said:
Hi, Richard. I've read several guesses, but nothing authoritative. My guess is that it is related to the problem of optically passing the Fire Now! instruction while the shutter has been open for a while. A radio device does not have that problem, of course.

A device in the camera's hotshoe can be instructed through the hardwired data pins.

This principle was included in the patents of 2002, which until recently determined the whole off-camera Canon system.
Click to expand...

Thanks Clive. That was my original guess, but the absence of remote second-curtain sync from the new RF guns (or even the old ST-E2 that uses barely visible semi-IR) doesn't fit with that. And also, I think Nikon can do remote second-curtain sync using only light-code.

It just doesn't make sense to omit this very useful feature with radio, and I mention the patents thing because I have a (very) hazy recollection that Nikon acquired some early Minolta patents way back in the day relating to flash. I've mentioned this a couple of times before, but nobody seem to know.
 
If I read it correctly, there is no provision in the Canon technology for transmitting a delay time before firing. Wouldn't do much good with Bulb, anyway. That may be because Nikon had already captured that capability.
 
Just Canon's weird way, and they have stuck with it for the radio transmission on their new systems.

Thank goodness YN make it possible.

I believe Canon implement SCS with the data pins on the hotshoe, rather than the centre pin, making SCS always problematic on a Canon.

Nikon implement it over the centre pin, making it far easier to utilise with PeeWees I guess.
 
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Hotshoe contacts:
R X R
R 1 2 R
R 3 4 R
where
R = rails = Ground. The contact surface is the underside of the hook.
X = standard x-sync
1 = Quench for film TTL
2 = Ready
3 = ETTL / sync mode / manual level etc Data flow
4 = Focus light

2CS is implemented through pin 3 as data, and requires a "code translator".

Canon has one benefit over Nikon - the code, and access to the camera's firmware, is available through the accessory shoe, making it much easier for YongNuo, etc, to work with the system.
 
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