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Old Jan 3, 2005, 4:28 PM   #1
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I'm having trouble finding what should in my mind be a fairly simple thing to obtain. Jessops don't have it and from a brief check online, it doesn't seem to be too common for other retailers to do so either. I was told I would have to buy all sorts of expensive connectors and adaptors and the like if I wanted to do this simple thing.

I want an off-shoe cable to connect my Fuji s602 to my Cobra D650 flash so I can better position the flash for macro etc. This would just be going from the hotshoe of the camera to the flash hotshoe converter and as the s602 has no ttl or any sort of extra pins all that would be needed was communication between the centre pins on each end so that the camera can fire the flash.

Where can I get such a cable in the UK and what are they generally called?

By the way, does anybody know anything about the Cobra D650, its spec, whether it is a high range, low range or mid range flash, etc? I believe it has a guide number of 32 but that's about all I know about it. It's been a good buy from ebay for £13.50 including postage but it is unfortunately apparently not a thyristor flash as it will not allow you to take many flash photos one after the other, although it is excellent in having many auto settings which is very useful for the s602.

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Old Jan 4, 2005, 9:55 AM   #2
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Morgoth wrote:
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I was told I would have to buy all sorts of expensive connectors and adaptors and the like if I wanted to do this simple thing.

I want an off-shoe cable to connect my Fuji s602 to my Cobra D650 flash so I can better position the flash for macro etc. This would just be going from the hotshoe of the camera to the flash hotshoe converter and as the s602 has no ttl or any sort of extra pins all that would be needed was communication between the centre pins on each end so that the camera can fire the flash.

Where can I get such a cable in the UK and what are they generally called?

In general, IMO, this could be called:
- remote flash sync cord
- flash sync extension
- ....
Nikon made exactly what you need, except that has extra Nikon dedicated hotshoe pin that you won't need:
http://www.adorama.com/NKSC28.html
The description is quite clear

Quote:
Nikon SC-28 Dedicated 3' TTL Coiled Sync Cord with Male & Female ISO Shoes, from Camera to Flash.

In generic accessories, you have to buy 2 items (adapters)

FYI:
http://www.stevesforums.com/forums/v...mp;forum_id=53

1) PC to Hot-Shoe Adapter
http://www.bhphotovideo.com/bnh/cont...414&is=REG


2) Hot Shoe to PC Adapter
http://www.bhphotovideo.com/bnh/cont...453&is=REG
This will give you a PC connection from the camera hotshoe. You put this on the camera hotshoe, and plug the first item's cord in the jack on the side.



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Old Jan 4, 2005, 10:24 AM   #3
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Morgoth wrote:
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By the way, does anybody know anything about the Cobra D650, its spec, whether it is a high range, low range or mid range flash, etc? I believe it has a guide number of 32 but that's about all I know about it. It's been a good buy from ebay for £13.50 including postage but it is unfortunately apparently not a thyristor flash as it will not allow you to take many flash photos one after the other, although it is excellent in having many auto settings which is very useful for the s602.

I can't find any specs, is it this flash?:

http://cgi.ebay.co.uk/ws/eBayISAPI.d...ayphotohosting



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but it is unfortunately apparently not a thyristor flash as it will not allow you to take many flash photos one after the other,
It's certainly a flash with a thyristor inside.
Taking many flash in rapid sequence is another question. Usually, Flashes which offer this possibility (called sometimes "winder mode" in reference to the film winder motor ) is simply set to a reduced power manual mode (1/16 or less) and allow to fire at around 5 fps . If you have a manual power setting , it will do.

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Old Jan 5, 2005, 5:52 AM   #4
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Thanks for your response. Hmm so the camera shop person was right, in the sense that it is either done with adaptors and a pc cord or with a dedicated cord which is a bit expensive and has extra pins that I don't need and could potentially harm a future camera that had extra pins in a similar place. I will search around to see if there are any cheap-ish dedicated cables. It seems to me to be odd nowhere expects you to need only the centre pin.

As to the D650 what I meant with regards taking a lot of pictures one after the other was that it doesn't let you fire it when it isn't fully charged, unlike two other flashes I've tried out, the Olympus T32 and some Nikon thing that belongs to a Nikon F3 my friend was loaned. You have to wait for a full charge to fire and I have been told this is the mark of a thryistor flash. Are they mistaken? What makes you say it has a thyristor in it?

The picture is definitely the same model as my flash, here are photos of the front and back of it. As you can see it has an lcd which isn't common in cheap flashes I've looked at in second hand shops, so that made me wonder exactly what level the flash is aimed at.




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Old Jan 5, 2005, 12:04 PM   #5
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dedicated cord which is a bit expensive and has extra pins that I don't need and could potentially harm a future camera that had extra pins in a similar place
You are right, but I believe it's better quality too. If you get this cord, you can also made a plastic isolation sheet which isolate the extra pins.

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You have to wait for a full charge to fire
All depends how the flash is fired. At full manual power setting , or TTL/Auto with a not well lighted subject, the flash fire at full capacity and "empty" the internal capacitor, thus , take max time to recharge. At partial manual setting, and TTL/Auto with well lighted subject, the flash stop before the capacitor got "emptied" , thus take less time to recharge.


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You have to wait for a full charge to fire and I have been told this is the mark of a thryistor flash. Are they mistaken?
They are right. In very simple flash, electronics parts is used to boost the voltage to charge the main capacitor, but the triggering circuit may be simply dry contact , like in most disposable cameras, and very cheap flash. But they are only full power flash, thus has to be recharged from zero each time.
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What makes you say it has a thyristor in it?
Because I know a bit how they are designed .
- A bit more sophisticated, a flash use a thyristor to drive it's triggering circuit >> more reliability (no more burned contact ) .
- A step further, flashes have to be able to shut themselves off when the light is enough (flash power is controlled by it's duration) and to do this, they use another thyristor to stop the current (quench circuit) in the flash bulb. Without electronic, it's impossible to do this.
This is the case off your flash, all TTL and Auto, and Manual partial power flashes design.

By the picture, I guess your flash can be use in Auto mode ( you press the F button to select the aperture value ?) , and manual partial mode.



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Old Jan 7, 2005, 4:26 PM   #6
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What I don't quite understand is though, why is it that other flashes can be fired when they are not fully charged up - ie, you can fire them before the 'ready' light is lit, and yet my Cobra D650 will not allow you to fire it until it has fully recharged and the light is lit? I have to wait for the flash to recharge before I can fire the flash again.

If a thyristor is needed for auto stuff then my flash must have one, but I don't get how it doesn't allow you to fire it when not fully charged.

Anyway thanks for your help, I now have a flash cable which I got at a second hand camera stuff shop for £4. Nobody knows what it is dedicated for, it does have extra pins on it, but in order to get the thing onto my camera I had to tape up the pins as they couldn't be pressed down otherwise. So far it's worked ok, although once or twice it hasn't fired when it should have done. Does anybody know what this is dedicated for? It may be impossible to tell from pins alone. It's not Pentax, anyhow.

[img]www.abandoned-scotland.omnia.co.uk/stuff/flash_pins.jpg[/img]
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Old Jan 8, 2005, 11:50 AM   #7
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What I don't quite understand is though, why is it that other flashes can be fired when they are not fully charged up - ie, you can fire them before the 'ready' light is lit, and yet my Cobra D650 will not allow you to fire it until it has fully recharged and the light is lit? I have to wait for the flash to recharge before I can fire the flash again.
Depending of the flash electronic design, the 2 facts can be related or not.
- In a flash with old ready light design, with a neon bulb for example , this circuit is completely independent of the triggering circuit, thus the ready light will glow up when it reach the neon voltage. The triggering circuit, which can be functional internally ( they send a high voltage pulse to the trigger terminal), but if the capacitor voltage is not reached yet, the flash bulb can't fire anyway.

- In some modern flash (I can't say all of them, I don't know) , the ready light is a led, and is part of the capacitor voltage monitoring circuit, thus the 2 facts are related, it glows the led and allow the triggering at the same time.

Quote:
If a thyristor is needed for auto stuff then my flash must have one, but I don't get how it doesn't allow you to fire it when not fully charged.
In all cases , you have to wait the flash to recharge to be able to fire , thyristor or not. There is no miracle , unless you design a flash with a bigger capacitor , or 2, or 3 capacitors with a electronic switcher (I did think about) , but then you get to the bulb limit which has a max energy to dissipate in a certain lap of time.


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Old Feb 25, 2005, 4:32 AM   #8
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If you are interested, I have a user manual for the D650, which I could either scan and email, or photocopy for you.

Let me know either way: [email protected]
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