One of the most common confusion which occurs with the Canon EOS flash photography is the fact that the Canon EOS modes like the Program (P ), Shutter Priority (TV) , Aperture Priority (AV) and Manual (M) modes handle flash illumination is different ways. This is especially so when the ambient light is not strong. This guide will give a brief run down of how the various modes work when the flash is activated. This guide also assumes that the FP mode is not turned on.
The P (Program) 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
With this mode, the Camera lets you decide the shutter speed instead. It will decide on the aperture priority settings to suit the shutter speed that you have chosen to make sure that the exposure level is correct. The flash pulse duration will be decided by the flash metering system. In essence the Camera will always function under fill flash mode when in TV mode. This is the opposite of the "P" mode. The Canon EOS system will also indicate to you if the background is too dark. You will see this warning when the Maximum aperture settings begin to blink in the viewfinder. If this happens, you have to reduce the shutter speed and use a tripod stand to hold the camera to avoid motion blurring.
Aperture (AV) 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
When you use the M Mode, you will determine the aperture and shutter speed of the camera. The exposure level will also be decided by you. The camera will just determine the correct flash duration to illuminate the foreground using the flash metering system. - 16752
The P (Program) 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
With this mode, the Camera lets you decide the shutter speed instead. It will decide on the aperture priority settings to suit the shutter speed that you have chosen to make sure that the exposure level is correct. The flash pulse duration will be decided by the flash metering system. In essence the Camera will always function under fill flash mode when in TV mode. This is the opposite of the "P" mode. The Canon EOS system will also indicate to you if the background is too dark. You will see this warning when the Maximum aperture settings begin to blink in the viewfinder. If this happens, you have to reduce the shutter speed and use a tripod stand to hold the camera to avoid motion blurring.
Aperture (AV) 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
When you use the M Mode, you will determine the aperture and shutter speed of the camera. The exposure level will also be decided by you. The camera will just determine the correct flash duration to illuminate the foreground using the flash metering system. - 16752
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
