Flash doesn't fire when the image is black

[kevinkt]

Pretty much I am trying to achieve a black background on my subject, but unless it's partially lit, I can't get my flash to fire. Is it just because my flash sucks? (Yongnuo Yn-560), or is there some kind of setting where I can make it fire even when my camera just sees black.

EDIT: MORE INFORMATION
Camera settings: Manual Mode. Aperture 1.8, shutter: 1/200, iso: 100. Manual Focus.

I'm using a Canon T2i.

And I played around with it some more, now it flashes like 1/5 times when the image is black. But when I add more light into the shot, it always flashes.

 

[sierramister]

What type of camera do you have? Turn your camera to manual mode and try it.

 

[kundalini]

Have you powered your flash ON?
Is it hotshoe mounted or OCF?
Are the batteries charged?
Are the batteries installed correctly?
Have you RTFM?

Flash photography does not require a positive ambient scene. You can flash in a totally blacked out environment. Read your manuals, both camera and flash.

 

[Trever1t]

lol@RTFM!

Shutter release but no flash? Camera and settings needed to assist

 

[kevinkt]

Yeah of course. As I said, everything works when I have a lit image, and then it does not when the image is black.

Camera settings: Manual Mode. Aperture 1.8, shutter: 1/200, iso: 100. Manual Focus. Hotshoe mounted.

I'm using a Canon T2i.

And I played around with it some more, now it flashes like 1/5 times when the image is black. But when I add more light into the shot, it always flashes.

 

[gsgary]

Yeah of course. As I said, everything works when I have a lit image, and then it does not when the image is black.

Camera settings: Manual Mode. Aperture 1.8, shutter: 1/200, iso: 100. Manual Focus. Hotshoe mounted.

I'm using a Canon T2i.

And I played around with it some more, now it flashes like 1/5 times when the image is black. But when I add more light into the shot, it always flashes.

WTF i don't have a clue what you are on about, put the camera in manual and the flash will fire, what effect are you trying to achieve ?
Also in the wrong forum because this is very basic

 

[Derrel]

What is with the aperture of f/1.8? THat's far too large an aperture for flash shots at normal ranges--it might in fact even be outside of the flash's capability!!! Try setting the aperture to f/4.8 or f/5.6,and see if the flash will work.

 

[KmH]

now it flashes like 1/5 times when the image is black.

:scratch: This is a confusing statement. When the scene you are trying to shoot is completly dark, or the image made when the shutter releases is black?

 

[OrionsByte]

Just a hail Mary but have you double-checked what mode the flash is in to make sure it's not trying to act as a slave or something?

 

[Overread16 4]

Is your flash itself firing in an auto mode or full manual (ie are you setting the power output of the flash yourself or is it doing it automatically).

If the flash is setting its own power automatically chances are when it is seeing a black scene its putting out its full power to try and light it all correctly. However that means it takes longer to recharge its capacitor for the next flash shot. So the 1/5 could be the result of you pressing the shutter button and taking a shot before the flash has had time to recharge.
And then when you're setting things and getting a brighter lit shot the flash is not needing to put out as much power, and thus it recycles at a faster rate.

What is with the aperture of f/1.8? THat's far too large an aperture for flash shots at normal ranges--it might in fact even be outside of the flash's capability!!! Try setting the aperture to f/4.8 or f/5.6,and see if the flash will work.

hmm you've lost me there - why is f1.8 too large of an aperture for flash at normal ranges?

 

[RockstarPhotography]

Its not the flash, you doing something wrong. The flash can't see how much light there is it doesn't care, it just gets the signal to fire and fires. Are you using ttl or manual?

 

[KmH]

Over exposure.

 

[Rocan]

it should fire in manual...

try switching cam/lens into manual focus, camera sometimes wont fire without focus, and it cant focus without light (or an auto focus assist lamp).

unless if camera is clicking but flash isnt firing?