"When you drive 3 hours for a "golden hour, woodsy" engagement session and drab overcast beats you there...."
I hid my 580ex (with a tungsten filter) in the woods and we got to work. It isn't quite as nice as the real thing, but it's a pretty good trick if you are in a pinch!
I only applied this to maybe half of the session. While I felt confident in the lighting, I didn't want to bank the entire session on my first real application of it. I also shot in burst so the flash would fire for the first frame but I would secure natural light images in between.
To break it down:
- I used a Canon 580ex on ~1/4 power with a full tungsten Lee's Filter taped on it.
- I put the stand maybe 15 feet behind them but entirely behind the tree or outside of the frame.
- If you can see the source it will look like flash-light and not real sun).
- I put the stand up to roughly horizon height.
- If the flash is turned up too bright, the brightness will overpower the color filter and you it will just look blown out. (notice I made this mistake slightly on his white shirt)
-Set your WB to 6000K and this will leave the natural cloudy light a little blue, and make your orange filter much more convincing.
-IN POST: You will need to grab the brush in Lightroom and make some local white balance corrections. I.e. if actual sky is visible in the image, you will need to add yellow to it to match the sun's color effect on the atmosphere.
-Lastly, when you use wireless triggers you (usually) have to meet the 1/250 sync speed on your strobe, so I think my settings were something like ISO 50, 1/250, and f/2.5.
Equipment wise: 1 8' light stand, 2 pocket-wizards, Lee's filter pack,1 580 ex, 50mm 1.2, Canon 1Dx.
Here is a link to a filter calculator that is AMAZINGLY HELPFUL: http://www.leefilters.com/lighting/mired-shift-calculator.html