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 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.
AV (Aperture Priority) Mode
If you are using the Aperture priority mode, you can determine the camera depth of field (DOF) when you adjust the lens aperture. What the camera will do instead is to adjust the shutter speed to expose the background to the right exposure. The duration of the flash pulse will be determined by the camera flash metering system as well. Pay attention that the shutter speed is set low or not. If the shutter speed is set low, you will need to use a tripod to hold the camera. Otherwise, you will end up with pictures which are blurred because of motion. Here in this mode, the camera will also work in fill flash mode just like under TV mode. Canon has several camera models which possesses a function which allows you to synchronize the X-Sync speed to the Shutter speed. The models which have this function are the Canon Elan II/ EOS 50 and the EOS10/10s.
M (Manual ) Mode
Under this mode, you will specify both the shutter and aperture speed of the camera. You will also determine the exposure setting of the camera. The camera will, through the flash metering system, calculate the flash output to illuminate the fore-ground.
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.
AV (Aperture Priority) Mode
If you are using the Aperture priority mode, you can determine the camera depth of field (DOF) when you adjust the lens aperture. What the camera will do instead is to adjust the shutter speed to expose the background to the right exposure. The duration of the flash pulse will be determined by the camera flash metering system as well. Pay attention that the shutter speed is set low or not. If the shutter speed is set low, you will need to use a tripod to hold the camera. Otherwise, you will end up with pictures which are blurred because of motion. Here in this mode, the camera will also work in fill flash mode just like under TV mode. Canon has several camera models which possesses a function which allows you to synchronize the X-Sync speed to the Shutter speed. The models which have this function are the Canon Elan II/ EOS 50 and the EOS10/10s.
M (Manual ) Mode
Under this mode, you will specify both the shutter and aperture speed of the camera. You will also determine the exposure setting of the camera. The camera will, through the flash metering system, calculate the flash output to illuminate the fore-ground.
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
