# Pushing up flash sync speed.



## jwbryson1 (Nov 26, 2011)

I keep reading in this forum that a camera's flash sync speed can be pushed beyond the manufacturer's specifications.  So, how is it done?

I have a D90 and a D40.  The flash sync speed on the D90 is 1/200 and on the D40 is 1/250.

I also have an SB-700.  Can the flash sync speed be pushed beyond the limit with just the built in flash or also with the SB-700?

Thanks.


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## SCraig (Nov 26, 2011)

One of the settings on the D-90 is Auto-FP (Custom Settings E-5).  Change that to "On" and it will synch up to about 1/2000 second depending on the flash.  I can get 1/2000 with both my SB-600 and SB-700 however the flash is forced to flash multiple times so the flash output is lowered.  A good explanation is here: Nikon CLS Practical Guide: 10. Auto FP High Speed Sync Explained


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## KmH (Nov 26, 2011)

Good link SCraig. :thumbup:


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## SCraig (Nov 26, 2011)

KmH said:


> Good link SCraig. :thumbup:


I had it bookmarked from when I asked the same question last year


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## jwbryson1 (Nov 26, 2011)

SCraig said:


> KmH said:
> 
> 
> > Good link SCraig. :thumbup:
> ...



Thanks for the information.  I tried it and it worked flawlessly.  Are there any issues with pushing up the sync speed in terms of damage to the camera or to the flash?  

Why don't they just make the sync speed higher from the beginning?


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## SCraig (Nov 26, 2011)

As it says in the link I provided, flash power is significantly reduced when shooting above 1/200 second.  Other than that, none that I know of so I just left mine turned on.


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## jwbryson1 (Nov 26, 2011)

Ken Rockwell has a really good explanation of why it's a bad idea to push about the FSS of any DSLR.


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## Village Idiot (Nov 28, 2011)

It turns the flash into a strobe basically. The D40 has an electronic hybrid shutter and should not have an actual limited x sync. If you can use some radio triggers that won't be so cheap that they affect the x sync or use a pc cable, it should work all the way up to the D40's max shutter speed.


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## Big Mike (Nov 28, 2011)

Yes, the main reason that Auto FP (or HSS in Canon speak) isn't really all that practical, is because of the limited output.  Sure, it can be very useful in some situation, when you can get the flash close to the subject.

Take the example of trying to underexpose bright daylight while lighting up your subject with flash.  One way would be to set your shutter speed to the camera's max sync speed and use your lowest ISO.  Then use the aperture that is small enough to underexpose the daylight and find out how much range/power your flash will have at that ISO/aperture combination.  

The other way to do it, would be to use Auto FP (HSS), thus allowing you to use any shutter speed to underexpose the ambient.  You can use a larger aperture, which will give more working distance with the flash, but it's still going to be really limited because the flash has to strobe.  This does give you the opportunity to use a large aperture for the shallow DOF, which you wouldn't be able to do with the first method.

The first method can use any type of radio flash trigger, which is certainly one reason why many people do it that way.  
The second method requires the flash to be camera mounted, or hot-shoe cord mounted or if don't wirelessly, it has to be with the CLS (Nikon) system.


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## kassad (Nov 28, 2011)

Village Idiot said:
			
		

> It turns the flash into a strobe basically. The D40 has an electronic hybrid shutter and should not have an actual limited x sync. If you can use some radio triggers that won't be so cheap that they affect the x sync or use a pc cable, it should work all the way up to the D40's max shutter speed.



I have heard Dave Hobby talk about this with the Nikon D40, D70 and  Canon  1D.   I wonder how well it would work with cheap radio triggers.   Anyone actually try this?


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## Garbz (Nov 29, 2011)

My experience is that cheap triggers haveenough problem pushing up to the normal sync speeds of the camera let alone a turbo cranked D40 or D70.


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## Destin (Nov 29, 2011)

When I had my d40, I could sync up to 1/500th with my sb-600 on a set of yongnuo triggers before the triggers started to fall behind.


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## Derrel (Nov 29, 2011)

If you want to push the synch speed of the D40 higher, a PC cord connection can get you up to the camera's top shutter speed using regular, single-burst (not pulsating HSS in Canon-speak or FP-Synch in Nikon-speak) electronic flash. Paul C. Buff, the owner/promoter/circus ringmaster at Paul C. Buff Inc. did some really great blog posts on his Alien Bee user's blog, posting under the name Fubb C. Laup a few years back. Since as you know, the D40 has no body PC outlet, you'll want to buy a HIGH-quality hotshoe to PC outlet adapter, and there is NONE better than the Nikon AS-15...mine is 10+ years old and working fabulously, still.

See my post from March of 2009, here: flash sync speeds....how can they sync over 250? what has changed


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