Flash Bracket For Twin Flash Guns?

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georgedingwall
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Post by georgedingwall »

Hi Dave,
Rotatable tripod mounting collar provided
As your lens has a tripod collar, if you mount that on the bracket, you will have even more room to choose the postion of the flash guns.

Good luck.
George Dingwall

Invergordon, Scotland

http://www.georgedingwall.co.uk/

DaveW
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Post by DaveW »

Good idea George!

It would only then be 6" from centre of tripod collar hole to front of extended lens.

DaveW

cannyman
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Post by cannyman »

georgedingwall wrote:Hi Karl,
Carl_Constantine wrote:That bracket also looks pretty universal, should work on any camera/flash system.
It is universal Karl, and has quite a large range of adjustment. It is also able to pivot the camera between landscape and portrait orientation without having to re-adjust the flash guns.

I ordered one yesterday, and it arrived at lunchtime today. It works fine with my D200 and pair of SB800s.

The only problem I've found is that I cannot use FP Synch on the camera when the camera is acting as commander for the two SB800s. I don't know if this is how it's supposed to be or if I have not found the setting yet. The work around I've used for now, is to designate one of the guns as the commander and the other as the remote. I then connect the commander flash to the camera using an off-camera SC17 cord.

In order to do this I had to remove one of the hotshoe adapters from the bracket and drill a clearance hole through the bracket so that I could use a tripod screw to attach the commander flash to the bracket.

This now enables me to use the FP synch option and get shutter speeds of upto 1/8000 sec with enough ttl flash power to capture my macro subjects. Who needs vibration reduction when you work at these speeds. 8)

Bye for now.
Are you sure you are shooting at 1/8000, thats certainly fast
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rjlittlefield
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Post by rjlittlefield »

cannyman wrote:Are you sure you are shooting at 1/8000, thats certainly fast
cannyman, this is an old thread and George may not be around for a while, so I'll barge in here.

1/8000 really is the minimum shutter speed on a Nikon D200. I believe that some of the Nikon cameras use an electronic shutter at high speeds, but the D200 is described by dpreview as a conventional
• Electromagnetically controlled vertical-travel focal plane shutter
• 30 to 1/8000 sec (1/3, 1/2 or 1.0 EV steps)
• Flash X-Sync: 1/250 sec

In practical terms, that means a narrow slit sweeps up across the sensor, exposing each pixel for 1/8000 second but taking 1/250 second to complete its travel. FP mode is required in the flash to make it put out light for at least the entire 1/250 second, albeit at reduced intensity. There is a huge light loss involved in slicing 1/8000 second out of 1/250 (or longer), but at close range what's left is enough.

Because various parts of the image are captured up to 1/250 second apart, this mode is not good for capturing fast subject movements like wings flapping. However, it should work just fine for avoiding blurs caused by camera vibration, as George suggests.

--Rik

Leif
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Post by Leif »

I might be wrong here, but I though the flash sync speed allowed the shutter to remain open while the flash went off. So basically if the ambient light is low enough, only the flash will record, and the effective shutter speed will be ~1/8000", or whetever the flash duration is. However if the ambient light is bright enough to record, then the exposure duration for that will be 1/250" assuming 1/250" flash sync. For macro work we stop the lens down lots, and that helps ensure that the ambient light does not record.

Harold Gough
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Post by Harold Gough »

Leif wrote:I might be wrong here, but I though the flash sync speed allowed the shutter to remain open while the flash went off. So basically if the ambient light is low enough, only the flash will record, and the effective shutter speed will be ~1/8000", or whetever the flash duration is. However if the ambient light is bright enough to record, then the exposure duration for that will be 1/250" assuming 1/250" flash sync. For macro work we stop the lens down lots, and that helps ensure that the ambient light does not record.
That is the general case for film cameras (I don't delve into the black arts of digital).

There can be pitfalls in using flash brackets from independant makers. In the 1980s I purchased a macro flash ring setup marketed by Kennet Engineering. Essentially, it has two arms which can each be locked in various positions for control of angles and flash to object distances. Each arm is on a rotating ring in the plane of the front of the lens.

All well and good when I was usuing manual flash with my Canon A1. However, the flash brackets are standard hotshoe ones which shorted out my Olympus OM T series flash guns. I had to place electrical insulating tape over the hotshoe contacts and fire my guns via the OM leads.

Harold
My images are a medium for sharing some of my experiences: they are not me.

rjlittlefield
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Post by rjlittlefield »

Harold Gough wrote:
Leif wrote:I might be wrong here, but I though the flash sync speed allowed the shutter to remain open while the flash went off. So basically if the ambient light is low enough, only the flash will record, and the effective shutter speed will be ~1/8000", or whetever the flash duration is. However if the ambient light is bright enough to record, then the exposure duration for that will be 1/250" assuming 1/250" flash sync. For macro work we stop the lens down lots, and that helps ensure that the ambient light does not record.
That is the general case for film cameras (I don't delve into the black arts of digital).
Digital sensor versus film has nothing to do with FP mode. It's all about how the focal plane shutter interacts with the flash.

There are two very different mechanisms.

The one you're describing is the most common, where the entire film/sensor is exposed at the same instant while a very short flash goes off.

The other mechanism is FP mode, where the flash is extended long enough to illuminate the film/sensor piecemeal, as the shutter slit moves across the focal plane. As explained in one of the posts linked earlier in this thread:
The trick is that in FP mode, the unit does not put out one big flash, but rather a string of very short low power flashes. The string lasts long enough for the shutter curtains to complete their movement, and the pulses come close enough together to produce smooth illumination even when the curtain slit is very narrow to produce a short exposure time at each pixel.
The real advantage of FP mode is that it allows a picture to be exposed almost entirely by flash lighting even when the ambient lighting is bright enough that it would record at 1/250 (or whatever the minimum sync speed would be). In terms of freezing action, FP is nowhere near as good as the usual single-pulse mode because different parts of the picture are exposed at different times, up to 1/250 second apart.

--Rik

Harold Gough
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Post by Harold Gough »

Rik,

I am no expert but I think the way you describe FP mode functioning is an update. Originally, I believe, it used great big, slow-burning FP bulbs. I should check that but it's nearly dinner time!

Harold
My images are a medium for sharing some of my experiences: they are not me.

rjlittlefield
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Post by rjlittlefield »

Harold, you're right -- FP mode in electronic flashes is a deliberate attempt to imitate the old slow-burning bulbs. As further explained in one of the postings linked above:
Take a look at http://www.mir.com.my/rb/photography/ha ... h/f280.htm ... describing the Olympus F280 flash that apparently introduced this technology.
--Rik

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