cgardner
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 p.1 #5 · Hand Held Light Meters | |
I've used every type of meter made over the 40 years I've been shooting, starting with the chart on the Kodak film box and my Dad's old Weston V. In the digital age I view a hand held meter as is more of a convenience than a necessity because exposure can be determined quite accurately using just the camera and a test target. I do use a Sekonic L-358 with my studio lights, but mostly for the convenience of being able to fire the lights with the meter via the optional PW transmitter module when "roughing in" the lighting ratio and exposure. I then rely on my eyes and the camera playback for the final determination of ratio based on how the shadow tone matches the context of the subject (age/gender/desired mood) and exposure based on clipping in the highlights, avoiding clipping during capture everywhere except specular reflections in catchlights and jewelry.
With a bit of experience and testing its possible to easily corollate camera feedback with the results in the RAW files. For example one day when doing exposure testing I tossed a white towel into a test scene to use the texture of the towel as a visual measure of overexposure. Because the detail of the towel starts to disappear at the point of overexposure is a better test object than just a white card. Going back and looking at the bracketed series in the camera I found I could accurately predict clipping in the RAW file based on the towel detail when the clipping warning appeared in same areas in the the camera playback. Since then I've relied on the clipping warning and a towel to tell me when highlight exposure is optimal. As is happens the towel clips at the same time as the red channel in skin, which should ideally be about 1/3 below clipping. So as SOP I raise exposure to the point where the towel begins to clip, then back down 1/3 stop. If I want to shoot at f/8 I'll set the camera aperture to f/7.2, raise the lights until I see clipping in the white towel, then stop down to f/8. Since I can remotely control the light intensity from the camera position its actually faster to do it that way than run back and forth with an incident meter. I've done it both ways and use what is most accurate and convenient 
For example if setting lights for a white background I'll set up a target where the face will be and adjust the foreground lights and aperture until the brightest highlights are just below clipping. In the setup below the brightest highlight were from the hair light...
Then I turn on the background lights, bring them up to the point they start to show clipping in the background (to judge evenness) then back them down until the background is dark enough to preserve the contrast of the rim lighting. That flies in the face of conventional wisdom of blowing out the background, but nuking the background really makes no sense perceptually and is just a poor work around for not being able to light one evenly.
Remove target, insert face, start capturing optimally exposed shots...
So in the studio the meter is just one of the tools I use. I could live without it, and have when the battery has died, but its more convenient to use it in the studio when initially setting up lights or replicating a previous set-up. When I want to repeat a set-up I'll first set the lights by eye and camera feedback (checked on the computer monitor) THEN measure all the lights individually from where the light hits the subject for my notes. Then next time I can duplicate the same look using the "by the numbers" blueprint. That's the value of a beginner learning to use a meter; they can follow a blueprint for a 2:1, 3:1, 4:1 ratio not having a clue what it should look like, stand back and visualize what is looks like. Its just like a carpenter building a set of plans from a house for the first time. But after building the same house for the 100th time the carpenter relies on the plans less. That's the nature of metering. The more experience you have with your lighting equipment the more you tend to rely on that experience and your eyes than metering everything "by the numbers".
Outside the studio I using ambient light and hot shoe flash I just rely on the camera feedback. I use a pair of Canon 580ex flashes. In ETTL wireless ratio mode exposure and ratio is simply a matter of selecting the A:B ratio needed for the desired tone/detail in the shadows then using the clipping warning and FEC to adjust the exposure as needed. When using the flashes in M mode I use pre-tested combinations of distances. For example if shooting location portraits I put my off camera flash an arm-span from nose to center of diffuser (about 6ft) then take four steps back (to 8ft) to shoot with Master / fill on my flash bracket. Because the distances are consistent, shot-to-shot and session-to-session, the ratio is about 3:1 and the exposure is always the same: f/8 when shooting with both lights at 1/2 power @ ISO 100. Doesn't matter of the person is dressed in white or black or what color their complexion is because the ratio and exposure fits the entire range of tone to the sensor.
FYI: Hand held meters don't work with Canon wireless or Nikon CLS because they use coded pre-flash from the flash head for commands, even in wireless manual mode.
Chuck
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