Flash changing shutter speed.

Dino f

Dino f

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Dean Feltimo
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Okay, probably being dumb here, but here goes.
I wanted to take a photo of someone against a blue sky.
I metered for the bright sky, and wanted to use a bit of fill to lighht the face up. The camera was on manual, 1/4000 @ f2.8 iso 100.
When i used the flash, i set it to 1/4 power, i didnt want to blow outthe face, but the camera kept changint the shutter speed to its max sync speed 1/250, thus blowing everything out. :bang:
Ant ideas, im sure ive not had this problem before on manual.
Dean:)
 
FP???
 
Dino f said:
FP???
Click to expand...

FP mode is high-speed synch mode. It will need to be engaged on the flash to allow shooting with the flash at more than 1/200 (or 1/250 or whatever your camera's synch speed is). If it's not engaged, the camera will limit the shutter speed.
 
I dig what youre saying MB, but i was exposing for the scene, and using the flash on 1/4 power, it made no difference when i went down to 1/64 power. If everything is on manual, then it should work to my settings, regardless of what the exposure will turn out like.
Dean:)
 
mr_pants said:
FP mode is high-speed synch mode. It will need to be engaged on the flash to allow shooting with the flash at more than 1/200 (or 1/250 or whatever your camera's synch speed is). If it's not engaged, the camera will limit the shutter speed.
Click to expand...

Oh hi speed, no it wasnt on, maybe ill give that a go, but see my above post, manual should do what i want it to.
Dean:)
 
The flash cannot light the scene in 1/4000th of a second. The shutter needs to be fully open (not a slit passing across the sensor) for the flash to cover the whole scene - hence the sync speed limit. If the flash has a high speed sync mode then you can use any shutter speed as the flash makes a burst of flashes to light the whole scene many times as the shutter slit passes the sensor.... least that's how I think it works :)
 
You forgot to set the flash to High speed
 
Cheers Guys, will have another play tomorrow:thumbs:
Dean:)
 
Why dont you do the same as before, but instead of 1/4000 and F2.8

Why not 1/200 and something like F9, 11, or 15 even?
 
Cheers for the suggestios guys,
Jamie- i wanted to shoot at 2.8 to throw the bg out of focus alot.
I did a few tests, and hs flash does work, its just not what i expected/ wanted to do, but hey ho.
Cheers
Dean:)
 
Put an ND4 on the camera that will allow you to meter to scene at 1/250th, iso100, f2.8. Thats within the sync speed so then you just need to dial in more power to the flashes to compensate.
 
Dino, forgive me if you've got this, but you seem a bit confused.

The problem is your camera has a focal plane shutter (google) like all DSLRs. You cannot use regular flash with this type of shutter at speeds shorter than 1/250sec (often longer) or you only get part of the picture exposed, so modern cameras lock you out of faster speeds with flash.

Some top-end flash guns have an FP (focal plane) or High Speed mode which pulses the flash rapidly, effectively turning into a continous light source for the brief time the shutter takes to function. If your flash does not have this function, you cannot use shutter speeds shorter than 1/250sec and must eithjer use a higher f/number, or an ND filter, as has been suggested, to get your shutter speed longer than 1/250sec.

FP/High Speed flash is great for the kind of thing you're trying to do, but it uses a lot of power and flash distance range is reduced.
 
Flash In The Pan said:
The following dslrs will flash sync well past 1/250 - Nikon D1/D40/D50/D70/D70s and Canon 1D
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Corrected. They go to 1/500sec by clever switching of the CCD sensor (CMOS won't do it). To be honest I didn't think any present cameras had this feature but the Nikon D40 is still current.
 
HoppyUK said:
Corrected. They go to 1/500sec by clever switching of the CCD sensor (CMOS won't do it). To be honest I didn't think any present cameras had this feature but the Nikon D40 is still current.
Click to expand...

The D40 will flash sync to 1/4000 and the D70/s to 1/8000 if you know how...
 
Dino f said:
Okay, probably being dumb here, but here goes.
I wanted to take a photo of someone against a blue sky.
I metered for the bright sky, and wanted to use a bit of fill to lighht the face up. The camera was on manual, 1/4000 @ f2.8 iso 100.
When i used the flash, i set it to 1/4 power, i didnt want to blow outthe face, but the camera kept changint the shutter speed to its max sync speed 1/250, thus blowing everything out. :bang:
Ant ideas, im sure ive not had this problem before on manual.
Dean:)
Click to expand...

You kinda answered your own question here buddy :)

Set your flash to E-TTL, enable high speed sync and re-shoot. Used to do fill in the sun with my 40D all the time:

1/2500s:
2545813892_a48c645b26.jpg


1/2000:
2544990001_06ae1ae0ed.jpg


E-TTL with FEV at -2 :)
 
Flash In The Pan said:
The D40 will flash sync to 1/4000 and the D70/s to 1/8000 if you know how...
Click to expand...

Do they? Without an FP flash gun? :thinking: I'd appreciate a link on that if you've got one. Thanks.
 
HoppyUK said:
Do they? Without an FP flash gun? :thinking: I'd appreciate a link on that if you've got one. Thanks.
Click to expand...

The D40 might operate the shutter electronically like a p&s by turning on and off the sensor to reach the higher speeds, which would allow you a high speed shutter sync as the whole frame would be exposed at once.

No idea if it does but thats the only way I could see it working. (Something tells me the original 1D was like that too?)
 
mole2k said:
The D40 might operate the shutter electronically like a p&s by turning on and off the sensor to reach the higher speeds, which would allow you a high speed shutter sync as the whole frame would be exposed at once.

No idea if it does but thats the only way I could see it working. (Something tells me the original 1D was like that too?)
Click to expand...

Yes, I think that's how it's done. But I thought they still only got up to 1/500sec, which is why I'd like to know more.
 
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