Confusion always results when users of Canon EOS camera tries to use the various modes available without trying to understand how they work. This is because the Canon EOS Camera has different modes like AV (Aperture Priority), TV (Shutter Priority), Program (P) and Manual (M) mode to handle its operations. The differences in they way they handle flash illumination is more obvious especially when the ambient light is low. This guide will give you a brief rundown on the various modes so that you will have a better understanding. We are also assuming that the FP mode of the camera is not turn on.
The Program (P) Mode:
Under the P mode, when the ambient light is low, the camera will be set to a high shutter speed to enable you to use the camera without a tripod stand. This is to enable you to avoid "motion blur" even though you are holding the camera with your hand. The P mode will work when the ambient light is low or high. When the ambient light is high, the camera makes the assumption that you will flash fill the foreground. Thus the flash will be low powered. If the ambient light is low, the camera will under the P mode will set the flash and the shutter speed appropriately to give the best possible result. Having said so, pictures taken under this condition will normally have a dark background.
The TV (Shutter Priority) Mode
Under this mode the camera will let you decide the shutter speed. It will instead choose an aperture priority to suit the shutter speed to ensure that the exposure level for the background is correct. The duration of the flash pulse will be determined by flash metering. In short, the camera always operates in fill flash mode under the TV mode as opposed to P mode. The Canon EOS system will also warn you if the background is too dim. This will be shown when the maximum aperture value of the camera lens starts to flash in the viewfinder. When this occurs, you should slow down the shutter speed. You will also require a tripod if you wish to avoid motion blur.
AV (Aperture Priority) Mode
Under this mode, you will be able to fix the depth of field by setting the lens aperture. The camera then decides the appropriate shutter speed to expose the background to the right level. The flash pulse duration will be determined by the metering system of the flash. However note that, if the shutter speed is set really low, you will need a tripod to avoid motion blur. As in TV mode, the camera will work in flash fill mode as well. The only exceptions to this are the Canon EOS 10/10s and Canon Elan II/ EOS 50 models. These cameras have a custom function which allows you lock the shutter speed to the X-sync speed.
M (Manual) Mode
With the M mode, you will choose both the aperture and shutter speed of the camera. You will also decide the exposure level of the camera. With the flash metering system, the camera will determine the correct flash pulse to illuminate the foreground. - 16039
The Program (P) Mode:
Under the P mode, when the ambient light is low, the camera will be set to a high shutter speed to enable you to use the camera without a tripod stand. This is to enable you to avoid "motion blur" even though you are holding the camera with your hand. The P mode will work when the ambient light is low or high. When the ambient light is high, the camera makes the assumption that you will flash fill the foreground. Thus the flash will be low powered. If the ambient light is low, the camera will under the P mode will set the flash and the shutter speed appropriately to give the best possible result. Having said so, pictures taken under this condition will normally have a dark background.
The TV (Shutter Priority) Mode
Under this mode the camera will let you decide the shutter speed. It will instead choose an aperture priority to suit the shutter speed to ensure that the exposure level for the background is correct. The duration of the flash pulse will be determined by flash metering. In short, the camera always operates in fill flash mode under the TV mode as opposed to P mode. The Canon EOS system will also warn you if the background is too dim. This will be shown when the maximum aperture value of the camera lens starts to flash in the viewfinder. When this occurs, you should slow down the shutter speed. You will also require a tripod if you wish to avoid motion blur.
AV (Aperture Priority) Mode
Under this mode, you will be able to fix the depth of field by setting the lens aperture. The camera then decides the appropriate shutter speed to expose the background to the right level. The flash pulse duration will be determined by the metering system of the flash. However note that, if the shutter speed is set really low, you will need a tripod to avoid motion blur. As in TV mode, the camera will work in flash fill mode as well. The only exceptions to this are the Canon EOS 10/10s and Canon Elan II/ EOS 50 models. These cameras have a custom function which allows you lock the shutter speed to the X-sync speed.
M (Manual) Mode
With the M mode, you will choose both the aperture and shutter speed of the camera. You will also decide the exposure level of the camera. With the flash metering system, the camera will determine the correct flash pulse to illuminate the foreground. - 16039
About the Author:
Tim Harris is a canon camera enthusiast. For tips on choosing and buying cameras, do check out Canon OS Camera website. Camera 40D Digital Rebel XTI 3D Blog
