Flash Photography Questions

NiVleK · 31st March 2004

Ok. Got a super newbie qn about flash photography... I just got myself a 550EX. I realised that even in indoor conditions with the 550EX, using Av mode on my 300D, the shutter speeds are still kinda slow at about 1/4 or longer. The resulting image looks very very bright to me but there were no overexposed parts highlighted.

BUTBUT If I use manual mode, and set it to 1/60 with the same aperature, the image still looks pretty much well exposed to me. Why is it like that ar?

firstmoon · 31st March 2004

the answer lies probably in the background, literally. how different the exposure of the background of your photos?

the exposure of a subject in flash photography depends only on the aperture, but not on the shutter speed. the shutter speed only affects the exposure of the background.

this is due to the flash light being faster (light a lightning) than any shutter speed that you might have used to take the photo.

NiVleK · 31st March 2004

Eh? Blur liaos.

di0nysus · 31st March 2004

Hi,

I'm also new to 300D + 550ex.

ok. there's 2 things to light up,

the background, this will be determine how bright it currently is, and u can meter it to see what is the shutter speed needed to expose the background correctly.

if u have a subject, in the foreground, this shld be lighted with your flash.

u mentioned your shutter speed is 1/4 secs? thats really slow and u can have good exposure in normal indoor lighting at abt ISO400 even w/o any flash, + the flash, everything will be even brighter. then u mentioned u change to 1/60...exposure looks the same. best if u can post a pic to see where/wat/background/foreground/subject is overexposed etc.

I"m not familiar with the manual settings of the flash yet.
I'm now trying to play with the ETTL +/- eV, and vary it with the exposure of the background, to create balanced effects or effects I want.

i have a pdf on fill flash, pm me your email if u want it.

happy flashing!

Zerstorer · 31st March 2004

Originally Posted by NiVleK

I realised that even in indoor conditions with the 550EX, using Av mode on my 300D, the shutter speeds are still kinda slow at about 1/4 or longer.

The reason for this might be because you have Slow-sync mode enabled.

mervlam · 31st March 2004

Edited and elaborated:

In P mode, the shutter speed is usually 1/60 at the lowest to enable handheld photography. The camera chooses a suitable aperture (usually the largest aperture, limited by maximum aperture of lens, in low light conditions). The flash will attempt to light up the foreground for proper exposure.

In Av and Tv mode, you choose the aperture or shutter speed respectively. The camera meters for ambient light and comes up with a suitable shutter speed or aperture respectively. The flash will then attempt to fill-in the foreground. In the Av mode case, shutter speed can be really slow if in low light conditions. For the Tv mode case, maximum aperture of the lens is the limit in low light if the camera fails to find a suitable aperture for proper ambient light exposure.

In M mode, you choose your own aperture and shutter speed values. The flash will attempt to light up the foreground for proper exposure.

Btw, the above is true for all Canon A bodies & ETTL EX flash

darrelchia · 31st March 2004

Read this ... i certainly found it useful, and u probably would too

Flash Photography for Canon EOS cameras

Cheers
Darrel

georgie · 31st March 2004

In av mode, the flash act as fill in.

there is 2 exposure. one is the ambient exposure and the other is the flash exposure. your 1/4 second is the ambient exposure and the flash exposure is determine by ettl.

generally to ignore amdient exposure which mean jsut use the flash to light the whole sence which may lead to dark background is to use P mode where the shutter speed is fixed at 1/60 or something close to it dependignon camera. this is the safest way. however the aperature might be fixed at f4 or f2.8 which is not too good when we wanna f5.6

av mode allows use to use f5.6 but there might be low shutter speed proble,. one way is to increase film speeed. but will have more noise.

can get the ball? else pm me

NiVleK · 31st March 2004

Hmmm,..points noted. Let me get home and try out again.

Belleforte · 31st March 2004

Check out this site. All you need to know about your Canon flash is here!

http://photonotes.org/articles/eos-flash/

31st March 2004	#1
NiVleK Member Join Date: May 2003 Location: Potong Pasir Posts: 696	Flash Photography Questions Ok. Got a super newbie qn about flash photography... I just got myself a 550EX. I realised that even in indoor conditions with the 550EX, using Av mode on my 300D, the shutter speeds are still kinda slow at about 1/4 or longer. The resulting image looks very very bright to me but there were no overexposed parts highlighted. BUTBUT If I use manual mode, and set it to 1/60 with the same aperature, the image still looks pretty much well exposed to me. Why is it like that ar?

31st March 2004	#6
mervlam Senior Member Join Date: Apr 2002 Posts: 2,422	Edited and elaborated: In P mode, the shutter speed is usually 1/60 at the lowest to enable handheld photography. The camera chooses a suitable aperture (usually the largest aperture, limited by maximum aperture of lens, in low light conditions). The flash will attempt to light up the foreground for proper exposure. In Av and Tv mode, you choose the aperture or shutter speed respectively. The camera meters for ambient light and comes up with a suitable shutter speed or aperture respectively. The flash will then attempt to fill-in the foreground. In the Av mode case, shutter speed can be really slow if in low light conditions. For the Tv mode case, maximum aperture of the lens is the limit in low light if the camera fails to find a suitable aperture for proper ambient light exposure. In M mode, you choose your own aperture and shutter speed values. The flash will attempt to light up the foreground for proper exposure. Btw, the above is true for all Canon A bodies & ETTL EX flash Last edited by mervlam; 31st March 2004 at 11:13 AM.

31st March 2004	#7
darrelchia Member Join Date: Jul 2003 Posts: 419	Read this ... i certainly found it useful, and u probably would too Flash Photography for Canon EOS cameras Cheers Darrel __________________ my website :: my blog

31st March 2004	#2
firstmoon New Member Join Date: Dec 2003 Posts: 47	the answer lies probably in the background, literally. how different the exposure of the background of your photos? the exposure of a subject in flash photography depends only on the aperture, but not on the shutter speed. the shutter speed only affects the exposure of the background. this is due to the flash light being faster (light a lightning) than any shutter speed that you might have used to take the photo.

31st March 2004	#4
di0nysus Member Join Date: Jul 2003 Location: macpherson Posts: 987	Hi, I'm also new to 300D + 550ex. ok. there's 2 things to light up, the background, this will be determine how bright it currently is, and u can meter it to see what is the shutter speed needed to expose the background correctly. if u have a subject, in the foreground, this shld be lighted with your flash. u mentioned your shutter speed is 1/4 secs? thats really slow and u can have good exposure in normal indoor lighting at abt ISO400 even w/o any flash, + the flash, everything will be even brighter. then u mentioned u change to 1/60...exposure looks the same. best if u can post a pic to see where/wat/background/foreground/subject is overexposed etc. I"m not familiar with the manual settings of the flash yet. I'm now trying to play with the ETTL +/- eV, and vary it with the exposure of the background, to create balanced effects or effects I want. i have a pdf on fill flash, pm me your email if u want it. happy flashing!

31st March 2004	#8
georgie New Member Join Date: Dec 2002 Posts: 44	In av mode, the flash act as fill in. there is 2 exposure. one is the ambient exposure and the other is the flash exposure. your 1/4 second is the ambient exposure and the flash exposure is determine by ettl. generally to ignore amdient exposure which mean jsut use the flash to light the whole sence which may lead to dark background is to use P mode where the shutter speed is fixed at 1/60 or something close to it dependignon camera. this is the safest way. however the aperature might be fixed at f4 or f2.8 which is not too good when we wanna f5.6 av mode allows use to use f5.6 but there might be low shutter speed proble,. one way is to increase film speeed. but will have more noise. can get the ball? else pm me

31st March 2004	#10
Belleforte Member Join Date: Jan 2003 Location: Central Singapore Posts: 320	Check out this site. All you need to know about your Canon flash is here! http://photonotes.org/articles/eos-flash/