Speedlite AF Assist Beam control

jms

« on: 02 / July / 2008, 10:24:09 »

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I've got a Powershot S5 and now a Speedlite 580EXII flash but was disappointed to discover that the latter's AF Assist Beam does not come on though I'm sure it would help focussing in dark places. The camera's beam comes on but is pretty feeble.

Given that a cheapo laser pointer helps focussing I'm sure the flash's would if only it came on.

Could CHDK sort this problem ?

Thanks,

Jon

« Last Edit: 02 / July / 2008, 10:28:13 by jms »

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DataGhost

314
EOS 40D, S5IS

Re: Speedlite AF Assist Beam control

« Reply #1 on: 02 / July / 2008, 11:13:50 »

Possibly. I have the same flash and the same issue. I just don't know how the protocol works (to enable/disable the assist beam), how it's sent to the flash in the first place and how it should be hooked into the green assist beam.

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kinematic

10
Canon EOS 50D - Former Powershot S3 and S5 owner

Re: Speedlite AF Assist Beam control

« Reply #2 on: 13 / August / 2008, 01:27:26 »

Quote from: DataGhost on 02 / July / 2008, 11:13:50

Possibly. I have the same flash and the same issue. I just don't know how the protocol works (to enable/disable the assist beam), how it's sent to the flash in the first place and how it should be hooked into the green assist beam.

Dataghost... do you think it's possible to control ETTL through the Tally light? What I'm thinking is to trigger the 580 EX to fire off the camera in it's slave mode? I do know it's a binary signal that is sent via the ST-E2 but wondering if it can be simulated through the Tally light?

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DataGhost

314
EOS 40D, S5IS

Re: Speedlite AF Assist Beam control

« Reply #3 on: 13 / August / 2008, 03:21:28 »

I have yet to see the wireless part in action, or it's invisible. Either way, I don't know the protocol so if it's at all possible, I'll need to know that first. I'm also not really sure of the tally light timing (accuracy) but it should be possible if it's instantaneous, only depending on the 'lag' (rise/fall speed).

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kinematic

10
Canon EOS 50D - Former Powershot S3 and S5 owner

Re: Speedlite AF Assist Beam control

« Reply #4 on: 13 / August / 2008, 12:14:47 »

Quote from: DataGhost on 13 / August / 2008, 03:21:28

I have yet to see the wireless part in action, or it's invisible. Either way, I don't know the protocol so if it's at all possible, I'll need to know that first. I'm also not really sure of the tally light timing (accuracy) but it should be possible if it's instantaneous, only depending on the 'lag' (rise/fall speed).

I suppose the other option would be to some how control the pre-flash and send the signal that way, however I'd think you'd need to put an IR filter onto the flash so it could be used as a trigger? Just a theory. Of course the hard part is still finding the protocol and I don't know if there's a huge demand out there to do this. I would love wireless flash control, and it would certainly mean that our P&S has another leg up on DSLRs that way. I kind of intend on getting the ST-E2 at some point, not sure I want to take it apart to figure out how it works, but might be the only way to learn the protocol and by that point for me, I already purchased the solution that I was hoping to avoid.

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kinematic

10
Canon EOS 50D - Former Powershot S3 and S5 owner

Re: Speedlite AF Assist Beam control

« Reply #5 on: 13 / August / 2008, 12:22:20 »

I found some more interesting information:

Everything Robotics • Information
The "E-TTL" protocol, as spoken by Powershot G3 and EOS 50, and a
speedlite 550EX

Sounds like a forum of hackers trying to understand the protocol... way above my head, but it sounds like if we can control the flash or the tally lamp, possibly we could control the flashes wirelessly. How cool would that be if accomplished with CHDK.

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winkman

Re: Speedlite AF Assist Beam control

« Reply #6 on: 02 / January / 2009, 12:41:07 »

Hi, is there meanwhile any possibility to use the AF-assist beam of an external flash? I've got a Powershot SX1 IS and would be very glad about such a feature in CHDK.

Thanks a lot!

Heiko.

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