600EX-RT Part III

In an earlier post I tested the Westcott Apollo Octabox with a couple of manual flash units.

When doing some research on the web I discovered that Phottix, a company that offers an ETTL trigger system to compete with Pocket Wizard Control TL and Pixel HK Kings, offers a 30 in octa that has the same build characteristics as the Westcott. Its a bit smaller. However it comes with a grid. So I ordered a couple of them in anticipation of the Canon 600EX-RTs arriving.

The octas got here about a week before the Speedlites but finally everything is in hand. The STE3-RT is still on backorder but a third 600EX-RT is providing the camera to remote control.

I am primarily interested in three things; A) how do ratios work in ETTL Mode, B) How does HSS work with Canon 5DII in ETTL mode, and C) how does HSS work with Canon with Speedlites in Manual Mode. Short answer; All the tests delivered as I had hoped. 600EX-RT works with 5DII to deliver HSS. The Speedlite runs out of gas at about 1/800 shutter speed at F5.6, ISO 100 shooting through the diffusion panel on the octa.

Here is the setup for the first test

As you can see I set the two octas up about 3 feet either side of Mannie. They are pointed at one another with Mannie toward the back edge of the modifiers. I used FEC in the 5DII to get proper exposure for the color checker since the ETTL exposure was being read off Mannie’s cheek which is about a stop above 18% gray.

Here is an example of the A:B ratio exposure set 1:1;

And here is one with the ratio set to 1:8. I try to keep the A and B Speedlites on the same side of the subject as the A:B in the display. It makes it easier to keep track of which light is being altered.

Here is an image shoot at ISO 200, 1/800, F4.0. In Lightroom the white square on the Color Checker is about a half stop under exposed compared to the baseline exposure at 1/200, F4.0, ISO 200. The exposure fell off quickly at higher shutter speeds. The diffusion fabric is probably costing about a stop of light. (Something to check.)

While the HSS test was useful, I also wanted to setup and use the Octas the way I would be inclined to use them on location. So, I moved Mannie in front of a window and took the diffusion panels off the octas. I put a grid on the octa that was positioned as the main light. The second octa was positioned over the camera as a fill light.

Here are two versions, first with A:B ratio set to 1:4 and second with ratio set to 1:2. The shutter speed is 1/320, ISO 100, F5.6. outside lighting is bright overcast. These two images have exposure pulled up one stop in Lightroom. That gets the black square on the color checker over exposed but gets the white square up to where it belongs. Normally I use a strong tone curve with my 5DII calibration preset to get the proper spacing between the black and white squares. The one stop pull was to apply the same exposure adjustment that FEC would have applied. I had set it back to zero.

Here is the setup shot for this test sequence;

The setup shot also shows the Paul C Buff mini-boom I use to permit tilting the octa on a light stand. The octa with the grid is on a Calumet Nano stand and is stable, even with the legs less that fully extended.

And the final test using Av mode for ambient light metering with +1 FEC for the speedlites, with a 1:2 ratio and -1 and -2 EC for ambient. The resulting exposures are ISO 200, F5.6, with 1/400 and 1/800 shutter speeds.

Based on this testing, it appears that the 600EX-RT in the 30″ octa from Phottix will work well for head and shoulder shots. Even in relatively bright environments or with windows in the background. That’s what I was looking for, something that is easily transportable for on-location shots in offices etc.

For those who might be interested the here is the URL to the Phottix store site www.phottixstore.com. The soft boxes and octas with construction similar to the Westcott Apollos are in the studio accessories section.