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Archive for February, 2011

Lesson Eight: Using the flash

In this lesson we will look at the different levels of flash power and discuss why it’s important to know how to dial you flash power down or up depending on the needs of the photo.

I’ll also explain how the flash and the camera’s shutter work together to synchronize the firing of the flash with the opening of the shutter.

Called the “Sync”

Let’s begin with Camera Sync:
The Sync is the action of the flash firing at the exact time that the camera’s shutter is fully open. this happens at a fraction of a second and is key to making sure the flash illuminates the subject at the moment it should..

When using wireless technology to fire flashes, you are limited to a certain speed in the high range; usually 250th second.

The delay as the data is transferred via wireless, is the inherent con of using a wireless off camera flash. Although 250th of a second is usually fine for most photo applications;  by using a Sync cord, which links the flash to the camera, Sync speeds can be avoided and the flash can fire at any speed that falls in both the camera’s and the flash’s capability.

Have a look at the image below, it shows a range of pictures taken at different Sync speeds, while using an off-camera flash setup.

The first frame is taken from the cameras fastest working Sync speed (250th sec)
At this speed the cameras shutter is told to stay open long enough for the transmitter to tell the flash that it’s time to fire.
As the Shutter timing is increased in speed, you can see how the Syncing of the two falls out of line, and the light from the flash becomes unable to affect the photo and thus useless. As the speed increases the camera eventually fires the shutter too fast for the wireless technology to keep up.

Most photographers will dial their camera to their fastest sync speed right away to see how much of the ambient they can “Kill”.

This means to bring the exposure of the scene way down so that ambient light has little or no affect on the photo.  Because ambient light is rarely constant, it is not reliable for photography where consistent light is required from the beginning to the end of a shoot.  Most professional shoots these days utilize made light, to ensure attention to detail and the ability to recreate exact conditions, time after time.

Let’s play around with flash power:  In the movie below, you can adjust the power on the Nikon SB-800 flash by clicking the + & – buttons.
The best exposure would be 1/16th power. Have a look at how much control is available in the varying power settings.

Most pro flashes will allow you to adjust the flash in increments ranging from 1/128th to 1/1. (full power)
Basic  on camera (built in) flashes will usually use a rating above or below zero. (-1.0,  -0.7, -0.5, -0.3, 0, +0.3, +0.5, +0.7, +1.0)

As you power up to 1/1 you can see how all of the detail in the center of the photo is lost.
As you power down you can see how dim light can create a mood and become next to unnoticeable.
Two or three flashes used together can create dynamic light that can help highlight the best aspects of your scene or subject.

Sometimes just a little extra light is needed to help freeze motion in a scene or to brighten your subjects faces.
Have a look on your camera for a button that has a tiny lightning icon.
Use this to enable your flash and sometimes to dial your flash power up and down.

On other cameras you may need to go into a menu to change the flash intensity.  It’s a good idea when shooting indoors to keep your flash set a couple stops down from 0,  keep it at -0.5 or -0.7 because rarely is a full flash needed indoors where light bounces off walls and ceilings.

When going outdoors and shooting at a distance, you can power up the flash a bit to throw light out to your subjects. Play around with the settings in between the action or at your leisure. Keep it fun, but don’t be surprised when tweaking little things here and there become half the fun of a great picture.

Please feel free to request topics for your photo learning needs.
I’ll be covering Lightpainting and astro-photography in the next lessons, as well as HDR (high dynamic range) photography.

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