Anyone look into disabling the Pre flash on the D-

gizz

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I've been thinking that possibly there would be a way to disable the preflash on the D-370. It may be controlled by an IC which would maybe make it difficult if not impossible.
Has anyone thought of this? It may be a bit much for my electronically handicapped mind but i'd be willing to check some things out.
 



shrtcirkt

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Gizz,
The flash on the D-370 has 6 settings, 2 of which do not use a preflash. (at least on my cams)
I do not get a preflash when in auto and forced flash modes.
The redeye, nighttime and the nighttime redeye modes guve a multiple flash.
And there is no double flash in the flash off mode.
Try it and see howitworks for you
 

gizz

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shrtcrckt - I think the pre flash that i'm referring to is not visible with the naked eye, meaning it occurs so quickly you don't notice it. I purchased a slave flash that was advertised as compatable with the D-370 but after further review it fires on the FIRST flash it sees and therefore is out of sync with the second shutter flash. I confirmed this by taking a pic of the slave flash unit with the D-370 in auto mode. Even though i saw the slave flash "fire", the picture that was taken showed NO flash from the slave and the picture was darker than those taken without the slave. I assumed that the slave flash lit up the area and the first D-370 flash made a decision based upon this and hence the picture was darker. I haven't messed with the D-370 much but i will to see if maybe there is a mode that'll work.

Are you using a slave flash with the D-370? If so, what brand/model are you using?
 

passgas55

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I hope the week after next to have my D370 and if it can flash just once ,I will buy one of them cheap wireless flash. I would like to know what is the idle draw on that unit being setup to use 2 AAA batts. Its either a low draw or the batts would not last very long.It does not have brains for flash auto adjustment so that might help. Full power all the way is how I am going to set it.I need to call Wolfcamera and see if they have any specs on that unit. I think I will email Olympus or call them to see if they have an answer for me.

(Edited by passgas55 at 6:16 pm on July 21, 2002)
 

shrtcirkt

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Gizz,
I have one slave that I use with my Sony digital and is not really good for the olympus. But I have used my lightmeter on the D-370 and it does not pick up any noticeble pre flash. I have a new flash that I am going to try with a P-nut slave unit i've got.
I'll try it tomorrow and see how it works. If it works ok, I'll post pics, if not I'll let you know.
 

gizz

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Thanks shrtcirkt.

Passgas55 - Please let us know on anything you find out from Olympus or Wolfcamera. Beware of Wolfcamera trying to sell you something else though. They are notorious for trying to sell you "extra" stuff with camera purchases.
 

Jon5ja

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Guys,

I have a couple of D-370s and mine definitely double-flash on AUTO and FORCED FLASH.  I'd never actually tried them on red-eye reduction until I read this thread -- man, that was freaky with all those flashes!

Anyway, I can only see the double flash if I'm looking the right direction or sorta watching out of the corner of my eye or something.  I can't always notice it.  Looking at it on my 'scope looks like there's about 70 mS between flashes, and if I'm looking at the camera when it flashes, the first flash blinds me enough that I don't notice that it flashes twice... but my little slave flash circuit notices.  I haven't been able to figure out any way to turn off the double flash on mine.
 

Hill Hopper

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I would NOT recommend turning it off if you find a way. It is used in the White Balance metering. Call me "chicken" if  you want, but I have a feeling your shots, possibly all of them, may absolutely visit the devil if you do. There are a ton of locations on the net where phtography buffs talk about this stuff, and flash delays for it. I researched a bunch a few months ago, even etched Db a board to try on a circuit he found. I strongly believe its one of those things you have to get around, not get rid of.
 

shrtcirkt

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Gizz,
I tested my D-370 tonight with my sunpak DS-20 digital flash and it showed definate improvement over the cameras flash. I cant post pics tonight because for some reason I am not able to upload from the camera on this computer. I'll upload some pics at work tomorrow for you to compare.
By the way, the sunpack has a built in slave and runs about $30.00.
After I post the pics let me know what you think.
 

gizz

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Thanks shrtcirkt!. I look forward to seeing the pics.
 

gizz

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Advice taken ******. Guess i was just tossing around ideas.
Jon5ja - What type of delay do you suppose would be needed to allow the flash to be in sync with the shutter? (The duration of the first flash + delay between flash of 70ms)?
 

Jon5ja

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Gizz, I saw one circuit where a guy actually had a "tunable" delay to fire a slave some amount of time after it saw the first flash.  However, it wasn't much less complicated (if at all) than the circuit I posted that requires no tuning.  It sets a flip-flop on the first flash, then after a few milliseconds, passes on anything else it sees that occurs with a few hundred milliseconds, causing it to ignore a first flash and then fire on the second one:
my slave trigger circuit

Though I haven't tried it or completely thought through to make sure it'll work, I also found an even simpler circuit (actually designed for a Nikon Coolpix 800) that is supposed to work if you're using a slave hot-shoe and a low-trigger-voltage flash at:
Charles Naumann's circuit for low-trigger-voltage flashes

I'm really curious to know if shrtcirkt's D-370 is behaving differently than mine -- when I tried to use a standard slave, it always made my pictures darker or didn't make any difference, depending on the flash setting.  Or, maybe the DS-20 is delaying the flash?
 

passgas55

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Thank you for contacting Olympus Digital Technical Support.

All Olympus cameras have this preflash and unfortunately, this preflash cannot be turned off.
 
The above is the response about the preflash. I wonder if the pre flash works off its own cap. then the main flash? Man I wish they hurry up and send my D370.
 

shrtcirkt

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Sorry I have not posted those pics yet, things are out of control at work and I have not had 5 minutes in front of my computer all week. I was able to get some information about the sunpak flash though.
Depending on how itis set up, the flash is capable of delivering approx a 400us flash duration. I figure that this flash is overlapping the pre flash and providing extra light on the tail end of it's cycle for the shutter. I'll try to get the pics posted before the weekend
 

JimYates

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shrtcirkt, did you get anywhere with the sunpak slave flash?   I'm looking at the Sunpak 018ST, Digital Flash it's got a 200ms firing delay.  If I can figure out a way to turn it on and off with Brian's board I might have something.  It's only $25.00.
 


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