D2X & Strob Synch

[Keith Cocker]

Hi,

When I used my D2X with some strobe lights today I had accidentally left the shutter speed on 1/250. The result was that one edge of the frame was dark (see attachment) . I presume that was from the shutter curtain. I had assumed that the D2X would be OK at this shutter speed with a strobe (Bowens Esprit 500). There was less darkening at 1/200 and it had gone by 1/160. I normally work at 1/125 so this isn't a problem buyt I wondered if what I was experiencing with higher shutter speeds was normal?

[Melody]

Hi Keith,

I'm normally at 1/125 myself however I'll try 1/250 with mine tomorrow and let you know what happens if no one else jumps in to tell us.

Melody

[Theo2005]

In other words: you worked with the simple X-sync, right?

Normally, in studios, the speed is 1/60. 1/125 should work fine too I suppose. Shorter than that is definately risky.

For instance, my new Metz MZ76 is only suitable for high speeds (over 1/125) when used with ttl, not with x-sync.

All in all I think that 1/250 should not be used in combination with powerfull flashunits/studioflashunits, if only because these units are capable of emitting long flashes like 1/150 for instance. You wouldn't get the full exposure at 1/250 sec with a flash that long.

The reason of the phenomena you saw is probably that the x-sync is far less precise compared to ttl flash.

So in studio, don't go over 1/125 and preferably lower, like 1/60. That way, no matter how long the flashduration, it will safely fall within the exposuretime. And even the less precise x-sync will work all the time.

Bottom line: this is NOT the D2X doing something wrong. It's the flash setup that needs a longer exposuretime to be set.

Theo

[Tom V]

The blackened edge on the image is typical of a too-short shutter speed during a flash illumination.

According to Nikon, the flash sync speed on the D2x is supposed to be 1/250 sec.

source: http://www.nikonusa.com/fileuploads/pdfs/D2X.pdf

According to Bowens, the flash duration for the Esprit Gemini GM500 is 1/925 sec. I assume this is the unit you have, or very close to it.

source: http://www.bowensinternational.com/catalog/product_info.php?products_id=117

The camera has flash sync modes that probably can reduce the maximum speed of successful flash sync, such as rear-curtain sync, etc. Make sure the camera is not set to rear-curtain sync.

The flash unit's flash duration is well within the time frame of the camera's 1/250 sync speed. Lower power flash bursts very likely have even shorter flash durations. Turning down the flash power usually results in a quicker burst of power through the flash tube, and results in a short flash duration.

Hopefully, the apparent problem is not a shutter speed duration or flash duration issue, but more likely a synchronization issue. If you delve into which direction your shutter curtain(s) are moving across the focal plane during the exposure, you can figure out if the underexposure is happening at the beginning or end of the exposure.

It is possible that the shutter speeds are off, and when you have 1/250 sec. selected, it is actually running at 1/300th sec. (for example). I think Nikon supposedly has some sort of internal shutter speed checking and correction built-into the camera, but how can you tell if that is working? If you get the same "dark-edge" result at 1/125th of a second, or Manual exposure results are not what expected, I would suspect the shutter mechanism is out of whack.

If you are using a wireless, IR, or slave-based flash sync scheme, either in whole or in part, I would investigate possible timing delays. Some fancy radio sync systems have adjustable flash sync delay controls.

In my studio, I use Speedotron 2400ws power packs, with the flash heads linked by high power cables (as opposed to a monobloc head that has the power and flash tube in a single unit). I would expect non-monoblock flashes to have a tiny bit of inherant flash delay due to cable length. Supposedly on my Speedotron system, the flash duration for a full power blast through one head is 1/300 or 1/350 sec. I shoot with my Fuji S2 at its maximum flash sync speed of 1/125 without problem. I shoot with my Nikon D70 at a 1/250 instead of its maximum sync speed of 1/500 with the Speedotron flash. If I was using a smaller flash, such as a Nikon Speedlight, I would not hesitate to use 1/500 sec. on the D70.

[Theo2005]

Actually Tom, his full flash is 1/350 sec.

But that's not the point I made. It's simply risky as well as unneccessary to use such short shutterspeeds in combination with studioflashes through a simple x-sync wire.

And what do you gain by using a short shutterspeed anyway? Simply set it to 1/60 (or 1/125 if you must, no need though) and let the flash do the freezing. Works perfect for portraits, always did. There isn't much (if anything) to gain from shorter shutterspeeds in these studiosituations, is there?

Theo

[Tom V]

Actually Tom, his full flash is 1/350 sec.

But that's not the point I made. It's simply risky as well as unneccessary to use such short shutterspeeds in combination with studioflashes through a simple x-sync wire.

And what do you gain by using a short shutterspeed anyway? Simply set it to 1/60 (or 1/125 if you must, no need though) and let the flash do the freezing. Works perfect for portraits, always did. There isn't much (if anything) to gain from shorter shutterspeeds in these studiosituations, is there?

Theo

Theo,

For 98% of studio work, your suggestion of 1/60th is perfectly fine, and gives plenty of time for flash sync. Usually, in a typical studio with low ambient light, shutter speed has nothing to do with exposure on the film/sensor, other than to be completely open during the time the flash is illuminating the subject. The flash duration is short enough to freeze low speed action. I have seen photos made with Speedotron's long flash duration (1/300 - 1/350) not "freezing" the hands on a moving model's outstretched arms, fan-blown hair, etc. Fashion photographers I've worked with usually wanted faster flash duration and would use more heads at lower power, or buy particular equipment specifically for shorter flash duration (and for faster flash recycling time). Another reason to shoot at a higher shutter speed would be to minimize the effects of on-set light sources, or to minimize ambient light (usually not a problem unless the ambient light is very bright).

Shooting flash or fill-flash outdoors, with its high ambient light, a faster sync speed is desireable. I would hate to be limited to 1/60 or 1/125 if the camera is supposed to sync at 1/250. Especially if I paid a premium for the camera.

But since Keith's system shows evidence of poor synchronization, I wonder what is wrong. I hope it is something simple to fix such as turning off the rear-curtain sync feature, and not something like a slow shutter.

[MikePL]

I've been shooting with strobes for over 6 years or maybe more. Shutter speed does not influence your exposure (unless you shoot in mixed lighting). So set the speed between 1/60 and 1/125 and you're OK for sure. I currently set it close to 1/125 because it annoys me to have a 'black viewfinder' with longer speeds. But the safest way is to use 1/60 and you will be absolutely positive that no problems arise.

[Keith Cocker]

Thanks Melody, Tom, Theo and Mike,

Tom hit the nail on the head with his mention of triggers! I knew that I had used 1/250 before with no problems (although I usually use 1/125). But that was BEFORE I bought my new Bowens Pulsar Radio Triggers :lol: I tried 1/250 with Pc cable and - no problems! With Radio Trigger anything above 1/125 produces the darkening.

Problem solved!!