Aperture and Program Mode

[a-z0-9]

Hi,

I have a 400D. I am curious about this characteristics of
aperature mode. Last night I was shooting some plants
in night condition. So I popped up the flash and decided
to turn the dial to shot. I found that the exposure is
basically above 1 second for all the various aperture
settings. Then with program mode I found a setting
easily for me to shot (below 1 second). My question
is: doesn't the aperature mode has a equal value
to the one in the program mode (below 1 second)?
Does it mean it is not possible to shot under aperture
mode under this condition?

I am using the stock lens that comes with the camera.
Thanks for advice!

[Adelfin]

Originally Posted by a-z0-9 Hi, I have a 400D. I am curious about this characteristics of aperature mode. Last night I was shooting some plants in night condition. So I popped up the flash and decided to turn the dial to shot. I found that the exposure is basically above 1 second for all the various aperture settings. Then with program mode I found a setting easily for me to shot (below 1 second). My question is: doesn't the aperature mode has a equal value to the one in the program mode (below 1 second)? Does it mean it is not possible to shot under aperture mode under this condition? I am using the stock lens that comes with the camera. Thanks for advice!

Hi,

think u can refer to this..

basically in Av mode, the camera tries to take a great photo, meaning it exposes the background properly, then fills the subject with flash to bring it out... as such, u can take it as the camera is trying to expose the background like it would without flash. Since it's too dark, it will take a long time, hence the >1 sec shutter speed...

in P mode, the camera acts like a consumer camera, and presumes u just want to light the subject properly with least handshake, so it chooses a handholdable speed and aperture, and uses the flash to make up for the rest, resulting in harsh flash on ur subjects...

to learn more about P mode, scroll up a little on the link i gave u... if u have time, try to read the whole article.. u'll learn alot about flash photography...

and for ur last qn.. under conditions that dark, use a tripod with Av/M, or handhold with Tv/P modes.. If you ever get an external flash, u might be able to handhold with a fast shutter speed if the background isn't too far away to use bounce flash and light it up..

[megaweb]

When the flash is ON,

in Aperture or Av mode,
check Custom Function (3)

0 or AUTO - the flash sync speed is set automatically within a range of 30sec to 1/200sec to suit the scene's brightness

1 or 1/200sec (fixed) - The flash picture can be taken without camera shake


in Program or P mode,
the flash sync speed is set automatically within a range of 1/60sec to 1/200sec

[Russ]

If you used largest aperture (smallest F stop number) for A mode in the conditions you mentioned, you will get the same shutter speed as P mode. You probably had the aperture set smaller (larger F stop) than the maximum so the camera compensates with a slower shutter speed.

[Adelfin]

Originally Posted by Russ If you used largest aperture (smallest F stop number) for A mode in the conditions you mentioned, you will get the same shutter speed as P mode. You probably had the aperture set smaller (larger F stop) than the maximum so the camera compensates with a slower shutter speed.

not necessarily.. coz it depends on how dark he was talking about. if it's so dark that it needs some time to light up the background adequately, the camera can choose to use a very long shutter speed.. note too the TS said that he tried all apertures...

remember, under Av mode, the camera tries to expose for the background, and use flash to light the subject, like a fill flash.. P just makes sure the subject is exposed properly...