Maximum Shutter Speed

Hi, would there be a difference to the maximum shutter speed at which one will be able to shoot your camera when using fibre optics to trigger the strobes compared to syncords, since with the fibre optics the camera flash will be firing.

No - the limit holds for the internal flash as well as any external unit.

The limit is not imposed by the flash or the trigger but bt the shutter mechanism.

Paul C

You can make your camera fire a flash at higher speeds than the synch speed by connecting it electronically with only 2 pins (Ground and Trigger) so that the camera does not know the flash is there (it will still send a trigger to the hot shoe for every photo). However, in this case you will not get strobe across the entire frame because of cut off from the shutter curtain.

The only Nikon DSLR you can exceed these synch speeds with is the D70 - which reverts to an electronic shutter at higher shutter speeds and therefore does not have the issue with the second curtain closing before the first curtain has opened fully (the flash is triggered when the first curtain is fully open).

Alex

I almost agree with paul. But with one slight caveat. Some cameras do not realize that a flash is attached when you use a syncord. And the camera will not enforce the maximum synch speed.

When you are relying on the camera's built in flash to be the trigger, ,the camera definitely knows that it is firing, so it will definitely enforce the maximum shutter speed.

So when you use a sync cord you MAY be able to bypass the camera's maximum synch shutter speed.

However this is of very little value because there is a good reason why the max synch speed is what it is. It is determined by the design of the shutter mechanism. When you do use a flash above the synch speed, there will be a noticeable shadow on part of the frame that was still covered by the shutter when the flash went off. This is not just a matter of timing, as at high shutter speeds there is never a time that the flash can go off and expose the entire frame.

That said it can be of some use on some cameras. For example on my 300D. The maximum shutter speed was 1/200. However I routinely shot at 1/250 with absolutely no noticeable shading. And if the shot was composed so that the flash shadow was over open water, I could bump it up to 1/320 and not notice the shadow.

Thanks for the info so far.

What i was think of is the following scenario with a setup using the fibre optics. Being on a dive, say towards the end and a pod of dolphins join you:) (it does happen:)) being in close to the surafce i would like to maybe use a shutter speed faster than 1/250 (which is the max flash sync speed for my camera) With such a setup I would be able to turn of the strobes, but not the camera's flash.

But if i understood correctly Alex, with connecting those two pins I would be possible to do so. However, does housings which rely on fibre optics have such connections or is it something i can buy seperatly and just slide into the hotshoe?

And in doing so, i in no way impacting on the way the camera fires its flash?

In the scenario you outline you are correct, I do not see any way on the Nikon to 'fool' the system.

On my D300 you can set the fastest shutter speed that is selectable when the flash is active ( as I believe it will in the above - the internal flash will be up and the processor will know it is 'on' ) - with D300 that looks to be 1/250 or maybe 1/320.

If you fire the flash via cable connection and only connect the two pins then you will be able to set any shutter speed you desire as the camera does not know that a flash is being triggered. You will only have manual flash control and NO TTL.

I almost agree with paul. But with one slight caveat. Some cameras do not realize that a flash is attached when you use a syncord. And the camera will not enforce the maximum synch speed.

Yes absolutely, it depends on the flash internals and the way that the chord is wired William.

Paul C

Some housings have controls that allow you to flip the flash up and down, although not all, by a long shot. Annoyingly for fibre optic users.

If you are using electronic connections - you can just turn off your strobes and use any shutter speed you like.

Alex

If you are using electronic connections - you can just turn off your strobes and use any shutter speed you like

Only guaranteed if you go all the way back to the hot shoe with the 2 wire connection Alex.

On my old Ike housing the camera always thought the flash was 'on', regardless of the powered state of the flashes so would enforce the shutter speed restriction.

Without the strobe present you could select any speed, so it wasn't the Ike TTL controller in the housing playing games - it was the strobe.

By the way Alex - flooded another Ike strobe that is two in a month, this one was a complete toaster, battery and main strobe sections filled in

Paul C

Only guaranteed if you go all the way back to the hot shoe with the 2 wire connection Alex.

 

On my old Ike housing the camera always thought the flash was 'on', regardless of the powered state of the flashes so would enforce the shutter speed restriction.

 

Without the strobe present you could select any speed, so it wasn't the Ike TTL controller in the housing playing games - it was the strobe.

 

By the way Alex - flooded another Ike strobe that is two in a month, this one was a complete toaster, battery and main strobe sections filled in

 

Paul C

MIne doesnt do that, if the flashes are off, the LED strip turns off. It is a Canon, maybe thats why? Or Ike has since fixed that issue somehow, by stopping a signal being sent to the hotshoe when it doesnt detect the main strobe is on.

Otara