Bright flash/narrow aperture setting?

[vanbinh]

Hi
I read from a Digital Photography tips: ( bright flash/narrow aperture setting) to make the close subject's background turn completely black.
Could anyone explain to me what it is and how to do it. I tried many times to make the background completely black or white but I never get it!
Thanks a lot!

[whoty]

You have to underexpose the shot and let the flash lighten only your subject.

[tkbslc]

Are you using studio flash or a flash on the camera?

[vanbinh]

Hi
I use flash on camera.

[wayne.robbins]

First off, you would be better off with a very powerful flash like a 580 ex II instead of the built in flash. The built in flash does not have sufficient power generally speaking.

Secondly, get your shutter speed at sync speed - i.e. 1/200th or 1/250th. You can either shoot in manual or av- but if in av, you need to change the av flash option to 1/200th or 1/250th sec. You will want to choose ISO 100 or so.

Get your camera so that the distant to the background is generally further away than the distance of camera to subject - i find this helps.

Set your aperture - dialing it down requires a more powerful flash..

Getting the flash off camera and illuminating from the front sides can help some too.

A simpler alternative that might work just as well is to set the flash to High Speed Sync and go with a much higher shutter speed.. Distance to subject needs to be much less because the flashes power output is less- but you can go with a much higher shutter speed- thus eliminating the background.

It's been so long since I've used the built in flash- do they even support HSS ? .. With a few flashes always handy, I've never tried. - nope- just checked- at least the 7D does not support HSS on the onboard flash.

[seoul4korea]

^^^ What he said. Shutter controls ambient so with a higher shutter speed you won't be able to exposue the background (Depending on how much ambient light there is. Then just set your aperture and get your flash set up the way you want it (Flash power, zoom, distance and angles and such) and you should be good. It would help if we knew what and where you where trying to shoot.

[vanbinh]

Hi
Thank you a lot!
I learn a lot from you all. I found very useful things from this forums when I can find Teachers and Friends.
Another thing I would like to ask, what do you think about this :
YN565EX E-TTL Flash Speedlite for CANON w/ i-TTL Remote ($168.64) I think this is made from China
And Canon 580EX II Speedlite Flash ($538)
Can I use the cheap one?

[seoul4korea]

Did you search the flash section? I think LOTS of people are using them.