Hi All, I have been trying to understand something on my 600D:
In P mode (which I have hardley used) the BI flash pops up when needed, everything is set automatically and results are good.
But in Av mode I am nost sure what is happening, as an example, say I am in low light conditions (flash down) and set the aperture to say 5.6, or the lowest it will go to for a given setting/lense/iso etc - I might get a shutter speed of 0"3, or 1"3 - so if I want to keep the iso and cannot increase the size aperture, I pop the flash.
But, this does not seem to auto sync the shutter speed, to take account of the flash now being deployed. instead, it seems that the shutter speed stays the same, so let's say it was 1"3 - and what happens next is I take the shot, the flash fires and the shutter stays open for the long time it was set at. So the flash is acting in addition to the settings, not taking control and changing the shutter speed?
I read in the manual that the shutter sync speeds are between 1/60th and 1/250th (or similar, not got it in front of me so cannot remember precisley) but the point is there is a range, so why does it not alter the ss in Av mode?
Is it just thinking that I want 'fill-in' flash (something else I don't understand is how it works out when to add supplimentary lighting as opposed to full power).
If I do the same in Tv mode, lets say I have a SS of 1/400 (I just tried this) and my aperture light is flashing, telling me to open it up, so I depoly the flash, and this time my SS dropped to 1/200th (maybe I moved the camera a fractrion) - but the ap is still flashing - the little lightning icon is lit to tell me the flash is ready and waiting to go. Obviously in Tv mode I want to be in control of the ss, but it does not seem to adjust the aperture to take account of the flash.
what am I missing, what do I need to understand?
Thanks
Ian
In P mode (which I have hardley used) the BI flash pops up when needed, everything is set automatically and results are good.
But in Av mode I am nost sure what is happening, as an example, say I am in low light conditions (flash down) and set the aperture to say 5.6, or the lowest it will go to for a given setting/lense/iso etc - I might get a shutter speed of 0"3, or 1"3 - so if I want to keep the iso and cannot increase the size aperture, I pop the flash.
But, this does not seem to auto sync the shutter speed, to take account of the flash now being deployed. instead, it seems that the shutter speed stays the same, so let's say it was 1"3 - and what happens next is I take the shot, the flash fires and the shutter stays open for the long time it was set at. So the flash is acting in addition to the settings, not taking control and changing the shutter speed?
I read in the manual that the shutter sync speeds are between 1/60th and 1/250th (or similar, not got it in front of me so cannot remember precisley) but the point is there is a range, so why does it not alter the ss in Av mode?
Is it just thinking that I want 'fill-in' flash (something else I don't understand is how it works out when to add supplimentary lighting as opposed to full power).
If I do the same in Tv mode, lets say I have a SS of 1/400 (I just tried this) and my aperture light is flashing, telling me to open it up, so I depoly the flash, and this time my SS dropped to 1/200th (maybe I moved the camera a fractrion) - but the ap is still flashing - the little lightning icon is lit to tell me the flash is ready and waiting to go. Obviously in Tv mode I want to be in control of the ss, but it does not seem to adjust the aperture to take account of the flash.
what am I missing, what do I need to understand?
Thanks
Ian
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