During our Basic photography workshop which happens in our select brand store Canon Image square, Beginners often ask,
” if I have a built in flash (pop-up) then why should I purchase a separate flash”.
Therefore, I decided to write briefly about flash this month.
What is Flash anyway?
It is an artificial Illumination of light electronically. It syncs with the Camera shutter with built in flash or by the hot shoe connector and automatically
fires when the shutter opens.
Flash Light is used where there is not enough light to lit up the subject and for also for creative lighting.
Technology Note:
There is a flash tube inside and a capacitor that holds electric impulse that is transferred all at once to the flash tube, which produces a short impulse of high power light.
Flash impulse duration is approx 1/2000th of second.
Key Notes:
Built in Flash (Pop-up) Speedlite (Canon Brand)
Speedlite advantage is that it can be put to creative use. They can be setup on and off camera both.
More than one light can be used with camera
Flash is used in Low Light to create artificial light and Day time to balance back and subject light.
Now the next question is if built in flash can help me achieve these effects. Why do I need a separate flash unit?
So let’s first understand the difference between the result of a built in flash and external Speedlite
Pop Up Flash / Speedlite
Now before we proceed further, lets understand some general terminology used in flash photography.
Speedlite Guide No.
The guide number for an electronic flash measures its ability to illuminate the subject to be photographed at a specific film or sensor sensitivity and angle of view. A higher guide number indicates a more powerful flash.
Guide No. of Flash helps in determining Aperture, as per the distance of Flash and Subject.
Or helps determine the distance the flash should be kept at as per the Aperture you set.
Key Notes:
1. Fixing your Aperture helps in manipulating Depth of Field.
2. Fixing Flash distance effects creative reproduction of light.
In case of Un Branded Manual Flash, This calculation is to be done manually or a separate Light Meter is to be bought.
What if you are using multiple flashes for a shoot and you have to calculate a common guide number for the flash set up. Then, what do you do?
Example:
Confusing!!!. Yes its confusing that would mean either you manually calculate the power for each flash or use the latest technology ETTL II in Speedlite which automates the camera to decide what should be the flash power of each unit as per the current setting.
E-TTL II Advantage
Distance between subject to flash is calculated by lens data, which provides accurate data. Focus assist distance calculation makes flash exposure calculation accurate. As this information cannot be read by third party flash it makes Canon Flash superior.
Key Note:
Automatic flash of third party read the reflected light back.
E-TTL II technology helps you by determine the combination of
- Flash to subject Distance
- Aperture
- Flash Power
- ISO and Shutter Speed are provided by the user.
- But E-TTL determines accurate Flash Power based on all this info
General flash techniques
Now lest understand few techniques we can use while using flash.
Backlit
Key Note:
Issue which is very common and occurs mostly is scene is backlit and subject itself is in shadow. If you compensate for subject then background will overexpose, shutter speed will go low for handheld shots. Remedy to it can be fill in flash which will bring a balance between background and foreground. Go to AV mode and popup in camera flash
Flash Exposure Compensation
Flash Exposure does not change Ambient Exposure. Ambient exposure is controlled separately through Exposure Compensation. This helps you manually fine-tune Foreground / Background Exposure of the subject
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Canon Speedlite Units
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Soon we will be conducting the Flash Photography in our CIS stores. So keep tuned for an extensive session…
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