Why does flash keep strobing?

[ianpinion]

Hi,

I've been out to a couple of parties in the last fortnight and been asked to take a few photographs of the guests who were in attendance. The lighting at both venues was quite low and I found it a real challenge to capture anything at the correct exposure. Generally I wouldn't use the flash on the camera indoors, but having turned the ISO up to 3200 and opened the aperture up as wide as it would go I was still struggling to get a shutter speed quick enough for me to still hand hold the camera and not get any camera shake. I do have image stabilization.

Anyway, I resorted to using the flash to give the lighting a bit of a boost. I half depressed the shutter to set the auto focus etc., but when I went to fully depress the shutter the flash just started strobing away and refused to take a picture. What am I doing wrong? What important little detail have I overlooked?

[cosmicma]

the flash strobes in low light to gain focus or / and reduce red eye

it could be you have your focus set on continuous focusing so rather than aquiring focus on half press and holding focus it's trying to refocus before taking the shot when you fully press the shutter

try putting the camera in manual focus and press the shutter if it fires with flash straight away then you'll know it's a focus issue
try using a different focusing setting and try again

[chris-p]

Yeah, it sounds like AF Assist to me.

[ianpinion]

I was inclined to think it was to do with the focusing, but the camera is set to single auto focus.

[flake]

It does help if you tell us the make & model of the caemra !! I guess it's a Canon as you mention IS, and you don't actually say if this is an external flash unit. However in the menus you will find a section which relates to the flash, and is titled 'emit beams' if you switch this off the flash will cease to strobe, but you may lose autofocus. The 580EX projects red lines to allow the camera to auto focus, this avoids triggering any slave units you might have.

[ianpinion]

Hi Flake,

I guess you've probably forgotten that I use an Olympus E620 and the flash in question is the one built into the camera. I was using it in conjunction with my 12-60 f/2.8-f/4 Pro Lens if that's any help.

[flake]

Forgotten? I never knew! dunno much about the Olympus system but I'm sure it's similar to all the others

[PaulMontgomery]

Sounds like red-eye reduction to me.

[chris-p]

The AF Assist will still work in S-AF or C-AF modes unless you turn it off (or at least it did on my E-510).

[ianpinion]

I think you could be right Chris. So either turn the AF Assist off or resort to manual focusing. I'll try that next time.

Thank you. Merry Christmas!