Question regarding using P mode with flash.

[Mascaporne]

I have been wondering for this for a super long time... and i cannot seems to find a proper explanation for this...

When u are using P mode with flash....
the setting is forever 60 shutter speed , 4.0 aperture .

I would have tot.... ok.. if i'm using flash, i can have a shutter speed of 1/60, when using an aperture opening of 4.0.

However, when i switch to Av mode (as an example) , when i tried to use 4.0 aperture again,
the shutter speed now drops to 1/2 sec .....

Or if using Tv mode, again, there's no way i could use the 1/60 sec speed again...

Why?? Can anyone help me explain this?

 

[ZerocoolAstra]

I have been wondering for this for a super long time... and i cannot seems to find a proper explanation for this...

When u are using P mode with flash....
the setting is forever 60 shutter speed , 4.0 aperture .

I would have tot.... ok.. if i'm using flash, i can have a shutter speed of 1/60, when using an aperture opening of 4.0.

However, when i switch to Av mode (as an example) , when i tried to use 4.0 aperture again,
the shutter speed now drops to 1/2 sec .....

Or if using Tv mode, again, there's no way i could use the 1/60 sec speed again...

Why?? Can anyone help me explain this?

This is most probably due to the flash sync speed settings that have been chosen.
I don't know where the settings are coz I'm not a canon user.

In P mode, what your camera is doing is locking the shutter speed to the flash sync speed which has been defined somewhere in your menus to be 1/60. The exposure is adjusted with the flash power, hence f/4 and 1/60 might still give you the same exposure levels on your subject if they are 1m away, 1.5m away, and probably even 2.5m away.

In Av mode, your camera is probably trying to expose for the ambient light, thus the 1/2s shutter speed.

Not sure why you can't dial in 1/60s in Tv mode though... sorry.

 

[Edwin Francis]

Using a Canon? Then these links may help:

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

especially this section:

http://photonotes.org/articles/eos-flash/index2.html#confusion

 

[horizon_grazer]

Although u never mention the camera brand u using but u mention TV mode, should be using Canon
Are ur focus point, lighting the same when u adjust the different shooting mode ?
Why u need the DSLR to decide for u, u should be deciding instead of the camera !