Thursday, June 2, 2011

Direct Flash From Above

Attaching your electronic flash to the end of a monopod has many advantages. It gets your flash high off the camera to all but eliminate red-eye. The additional height casts a longer shadow, improving the three-dimensionality of your subjects. The shadow will be cast well behind the subject. Finally, it allows some flexibility to move your light from the left to right of camera, depending on the effect you wish to achieve.

For this shot, I simply held up the flash / monopod combination and took the photo. Nothing remarkable, but you will notice that the face has some additional 3-dimensionality that would be absent had I left the flash mounted to the hotshoe of the camera.

While the photo itself is somewhat unremarkable, it represents some basic approaches to exposure when using a flash for additional illumination. For the record, the camera settings on my Nikon D70 were as follows: Shutter Speed was 1/1000 second, Aperture was 5.6, ISO was 200, and White Balance was Cloudy.

Flash Synchronization at 1/1000th of a Second?
Yes, Virginia. The Nikon D70 / D70s has a maximum native synchronization speed of 1/500th of a second. But if the camera doesn't realize a flash is attached, it can sync at any speed.  The unusual feature is shared by the Nikon D40, the D50, and the D1/D1X/D1H bodies. All this without going the High Speed Focal Plane Synchronization. The only limiting factor is the actual duration of the flash itself. You connect the flash and the camera by getting a Nikon AS-15 Sync Terminal Adapter for your camera, and connect your Nikon flash with the appropriate cable, using a Nikon PC Male to PC Male or its equivalent. If you are using a flash other than a genuine Nikon unit, you're better off using a Wein Safe Sync. See below.

Determining the Base Ambient Exposure
If you examine the shadows of the spectators in the crowd, you will notice that they point to camera left with a slight inclination towards the shooter. This tells me that they are essentially backlit, with a slight rim of light to camera right. If I use the tried and true “sunny sixteen rule” for exposure for our ISO of 200, the correct settings for a normally exposed background would be 1/200 second and an aperture of 8, or to extrapolate, 1/400 at 5.6. By increasing the shutter speed to 1/1000, I have underexposed the crowd by 1 1/3 stop. I also managed to keep the yellow feathers from completely “blowing out”, or losing all detail in the highlights. You may wish to make a test shot or two and decide what works best for you.

Setting Your Flash-Automatic Setting
You must now match the flash output to the selected aperture. I was using a special Vivitar 283 that had been modified to take a Lumidyne reflector. See Disclaimer below. This in and of itself is not significant, but the manufacturer claimed that the small, parabolic reflector gave a more even, easier to control light source, a supposition I’m willing to take on faith. I then set the flash to provide a proper automatic exposure at 5.6, the pre-selected aperture, at ISO 200. For this unit, that was nearly a full flash discharge. There was also a ¼ CTO gel to warm the flesh tone a bit. No umbrella was used, since I needed all the power I could get.

The final image has a central subject clearly separate from the background by the relative brightness coupled with  the rim of light on the subject's left.

Wein Safe Sync
Now there are some tricks that are unique to the D70 family of cameras. The biggest advantage is full flash synchronization at all speeds if the camera doesn’t realize there’s a flash attached. In order to achieve this, I attached a Wein HSHSB Safe Sync adapter to the camera. The Safe Sync is attached to the flash using a locking PC-Household flash cable. With this setup, the 1/1000 second flash synchronized exposure was entirely possible.

Disclaimer: The Vivitar 283 has the earned reputation of burning out hot-shoe equipped cameras due to it extremely high triggering voltage. It is recommended that these flashes, and other flashes made in the last century, should NEVER be attached directly to the camera. I will not enter the debate concerning the safety of the Japanese, Korean, and Chinese iterations of the flash. If you decide to experiment with these older units on a modern camera, you do so at your own risk.