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TTL and Ikelite in digital housings


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#1 bobjarman

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Posted 22 February 2002 - 01:48 PM

Prob a stupid question, but here goes anyway.

My understanding of the sensor system in the Ikelite housing with the DS strobes functions by reading the internal flash, and bsically mimicking it?

If this is correct, and you put a plate in the front of your housing to block the flash from firing outward and creating a lot of backscatter, how does the internal flash get the proper readings to determine what the exposure and lighting should be?????? The flash preflash would never reach the subject?

thanks in advance!

Bob

#2 MikeO

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Posted 23 February 2002 - 04:13 AM

Hi Bob,

You are correct in that the Ikelite DS-50 and DS-125 strobes mimic the internal flash. In fact, they mimic both the preflash and the main flash. This works just fine when you block the internal flash as long as the internal flash can still be seen by the strobe's slave sensor. The reason it still works is because the sensor in the camera that sees the flash isn't on the flash itself but elsewhere on the camera (on the Nikon Coolpix 990 and 995, it is on the swivel head, next to the lens; on the Oly cameras, the flash sensor is inside the lens assembly somewhere; on the Coolpix 5000, it is between the top of the handgrip and the internal strobe). So, as long as you block the internal flash in such a way that the Ike slave sensor can still see it and don't block the camera's flash sensor, the Ike strobes should work as designed . . .

Mike O

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Canon EOS 40D in Seatool housing, 100mm macro, Tokina 10-17, INON Z-240s.


#3 bobjarman

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Posted 23 February 2002 - 06:04 AM

Thanks. I figured it was something like that!

Just couldn't figure it out!

#4 wormguy

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Posted 23 February 2002 - 12:49 PM

Hey there Bob,

I agree with how the slave and DS50 flash is "supposed" to work, but my images don't seem to sync with the DS50 (I use a Canon G2 and Sea & Sea wide angle). What have you done to get everything to play nice together?

#5 bobjarman

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Posted 23 February 2002 - 02:24 PM

I haven't tried yet, mines all on order. G2 Ikelite Housing, twin DS125 strobes

Ill report back when I get it and set it up

#6 Decomike

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Posted 24 February 2002 - 12:10 AM

Wormguy,

until now it looks like our setup Canon G2 + DS50 is working ok. No problem with the sync.

We did have a sync problem with our old camera, Canon Ixus 300. We also didn't have a solution for this problem.

See our examples on http://members.tripodnet.nl/duikfoto

Mike.

#7 derway

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Posted 25 February 2002 - 08:40 PM

I'm using the G2/Ike/ds-50, and optical slave device. No problems.

What mode are you shooting in? I recommend Av, evaluative metering, flash forced on, (no red eye). Then play with aperature and flash exposure comp, to see what you get.

Sure you have one of the new digital slave devices? The older slaves, would dump it all on the preflash, and have nothing left to give, which sounds like what you are seeing...

Don
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nikon n90s/ikelite housing/twin SS-200 canon G2/ikelite/DS-50/optical TTL slave
sony V3/ikelite/DS-51/Heinrich DA2 slave