changing aperture for flash photog

Hi,

This seems like a silly question, but what is the best way to change the aperture for flash photography. Normally in non-flash photog, I would just spin the dial in Av mode. But with flash (indoors), the Av mode "exposes" for the background, which means it gives long shutter times (something like 1/10 sec), which blurs things, and allows the ambient light to creep in (like awful CFL lighting). I discovered with a custom function, that I can set the shutter speed in Av mode to be fixed at 1/250 sec., then pictures come out as expected. So, by using this custom function (can't remember the number), is this the best way to change the aperture? I would still like to take advantage of ETTL mode of the flash. Thanks.

Put the camera in manual mode, leave the flash in ETTL. It works just fine.

chantu wrote in post #11341360
Hi,

This seems like a silly question, but what is the best way to change the aperture for flash photography. Normally in non-flash photog, I would just spin the dial in Av mode. But with flash (indoors), the Av mode "exposes" for the background, which means it gives long shutter times (something like 1/10 sec), which blurs things, and allows the ambient light to creep in (like awful CFL lighting). I discovered with a custom function, that I can set the shutter speed in Av mode to be fixed at 1/250 sec., then pictures come out as expected. So, by using this custom function (can't remember the number), is this the best way to change the aperture? I would still like to take advantage of ETTL mode of the flash. Thanks.

As Titus 213 said... put your camera into manual mode. On your 30D, in manual mode, the finger dial will adjust the shutter speed, and the thumb dial (at the back of the 30D) will adjust the aperture. Set your shutter speed to 1/250s and adjust the aperture to your heart's desire.

Thanks guys. Flash and non-flash photography are two different animals. I'm going start playing with this in my portable studio at home with 2-580ex's and 1-550ex.

GeneMan88 wrote in post #11341449
As Titus 213 said... put your camera into manual mode. On your 30D, in manual mode, the finger dial will adjust the shutter speed, and the thumb dial (at the back of the 30D) will adjust the aperture. Set your shutter speed to 1/250s and adjust the aperture to your heart's desire.

Or...in manual mode on the camera meter the background and underexpose it as much as you would like staying within the flash parameters of under 1/250 and fast enough to hand hold, recompose ignoring the in camera meter, and shoot. The flash in ETTL will figure it out and add the light needed to the foreground up to the max output of the flash.

Titus213 wrote in post #11342561
Or...in manual mode on the camera meter the background and underexpose it as much as you would like staying within the flash parameters of under 1/250 and fast enough to hand hold, recompose ignoring the in camera meter, and shoot. The flash in ETTL will figure it out and add the light needed to the foreground up to the max output of the flash.

Thanks! This really works. I got tripped by the camera's meter since its not too useful without the flash. Now I can play with the aperture to control my DOF, and the 1/250 sec shutter is plenty fast for me to handhold.