A Different Look at Metering Strobes Outdoors
By Stephen A. Dantzig, Psy. D.
There have been several questions regarding the use of strobes outdoors lately. One of the more recent questions focused on a critical aspect of successfully using strobes on location. The simple, yet profound question was something like “How to you meter for the strobe when outdoors?” The technical end of this question depends on your meter and whether it can record ambient and strobes at the same time. The question triggered a different thought process for me. For me, the process of how I meter a scene that will include a strobe is as or more important than knowing how to set the meter.
Combining strobes with ambient light was a very difficult process to learn—until I shifted my thinking about how I went about metering the scene. My process of metering in the studio was well established: I’d set the exposure for the main and fill sources first and then decide the values of any and all accent/hair/background lights relative to my main/fill exposure.
Three spotlights and a 40” 60” softbox were used as co-main lights in this variation of fashion/beauty lighting. The overall exposure was f 8 8/10. Two spotlights were used to light Debbie’s beautiful thick black hair. These spotlights were fit with 40 degree gridspots and exposed at f 11. The camera was set at f 9. The decision of how to expose the hair lights was based on the main/fill exposure and the size of the light sources.
The idea of setting the main exposure first and then manipulating the background did not translate easily to outdoor settings for me. I learned [the hard way] that my best results came from working with what the scene provided and setting my strobe/ambient exposure around THAT value—especially when the background is much brighter than where my model is positioned.
This is a perfect example of the type of situation that I deal with all the time. The background is beautiful—deep blue ocean, blue skies, great foreground, and oh yeah, a beautiful young lady! This shot was actually part of a series of senior portraits for Jill.
The problem is that the shot did not exist until we created it. Take a look:
This scene was shot for the background at f 9 at 1/500th of a second. The location is beautifully exposed here, but Jill is badly underexposed.
In contrast, we totally lose the background and create a badly flared exposure when we meter for Jill in the shade. This exposure was f 4.2 at 1/125th of a second—about four stops difference! For you math fanatics out there, the background is about 800% brighter than Jill in the shade! [1 stop=100% more light; 2 stops=200%; 3 stops =400% and 4 stops=800%] There is NO way to save either of these images.
I cannot change the back light like I can in the studio. I can, however, change the light illuminating Jill by adding a strobe. I know what the background exposure is—and I know that my strobe will not have any impact on the background because of the inverse square law. I can know set my strobe/ambient to create the balance I want: I can set my strobe/ambient exposure to be greater than the background—and darken the setting behind her, or in this case I can set is to be slightly less than the background to create a more pastel colored scene. [The final exposure was f 6.3 at 1/500th of a second]. I am not as concerned with the lighting ratio because the strobe is definitely the main light. I try to angle the light to create shadows and depth and I try to position the strobe so the direction of the light coming from the strobe looks natural. My meter can read strobe plus ambient so I simply place the dome of the incident meter at her cheek aimed at the camera and fire the strobe. I compare the reading to that of the background and make any adjustments and start shooting!
One thing to be aware of is when the direct sun adds a potentially bright accent light. In this case the sun is acting as a non-front light and is metered with the dome aimed at the sun. This exposure now becomes my base to go on because highlights blowout so quickly. I have to make sure that my strobe/ambient combination is less than one stop under the highlight exposure. The bright background will be beautiful using this method too.