This guide covers metering techniques for studio lighting, from basic incident metering to multi-light ratio measurement.
This guide assumes you've completed:
Studio Metering vs Outdoor Metering
Outdoor photography often uses reflected metering (measuring light bouncing off subjects). Studio photography typically uses incident metering (measuring light falling on subjects).
Why incident metering for studio?
- You control the light, so you want to measure what you're providing
- Subjects of varying brightness (white dress, black suit) need the same exposure
- Results are consistent regardless of subject reflectance
This guide focuses on incident metering techniques for controlled lighting.
Quick Start: Practical Metering Workflow
If you want to start shooting right away, here's the essential workflow:
- Set your working aperture (f/8 is a common starting point)
- Meter the key light — adjust power until you get your target aperture
- Meter the fill — adjust for desired ratio (1:2 = one stop less than key)
- Meter the background — adjust for desired separation
- Take a test shot and refine
The sections below explain each step in detail.
Handheld Light Meters
In the studio, a handheld meter is far more useful than an in-camera meter.
Why Handheld Meters?
Camera meters (reflected):
- Measure light bouncing off the subject
- Affected by subject brightness (white shirt reads differently than black)
- Can be fooled by contrast
- Don't know what you want to expose for
Handheld meters (incident):
- Measure light falling on the subject
- Not affected by subject brightness
- Give consistent results regardless of subject
- Tell you what exposure will make middle grey render as middle grey
Incident vs Reflected Metering
Incident metering: Meter has a white dome (lumisphere) pointed at the light source (or camera). Measures light falling on the subject.
- Point dome toward camera → measure all light hitting subject
- Point dome toward each light → measure that light's contribution
- Not affected by subject reflectance
- Standard for studio work
Reflected metering: Meter has a small acceptance angle, measures light reflecting from subject toward camera.
- Spot meters (1-5° angle)
- Measure specific tones in the scene
- Useful for Zone System work
- Affected by subject reflectance (must interpret)
Positioning the Meter
For the main (key) light: Stand at the subject position, point the dome toward the key light, and take a reading. This tells you exactly how much light that source is contributing.
For overall exposure: Stand at the subject position, point the dome toward the camera (this averages all light hitting the subject from the camera's perspective). Use this reading as your shooting aperture.
For fill light: Turn off (or flag) the key light, meter the fill alone, then compare to your key reading. The difference in stops determines your lighting ratio.
Meter Recommendations
Budget options:
- Sekonic L-308 series (basic flash and ambient)
- Gossen Digisix (compact, limited features)
Mid-range options:
- Sekonic L-478 series (touchscreen, comprehensive)
- Gossen Starlite 2 (built-in spot meter)
Professional options:
- Sekonic L-858 (radio trigger integration)
- Older used meters often excellent value
Features to consider:
- Flash metering (essential for studio)
- Incident mode (essential)
- Spot metering (useful but not essential)
- Radio trigger integration (convenient but not essential)
Flash Metering
Metering flash requires capturing the brief burst of light.
How Flash Meters Work
Set meter to flash mode (sync cord or cordless trigger)
Position meter at subject, dome pointed toward camera (or light)
Fire flash (via sync cord, trigger, or manually)
Meter displays aperture for correct exposure
Sync Cord Method
Connect sync cord from flash to meter's PC socket. Press meter's trigger button—flash fires and meter reads.
Advantages:
- Reliable triggering
- No extra equipment needed
Disadvantages:
- Tethered by cord
- Awkward with distant lights
Cordless/Trigger Method
Meter waits for flash to fire (triggered by radio or manual button). When it detects the flash, it takes the reading.
Advantages:
- No cord needed
- Work freely around studio
Disadvantages:
- Must press meter button before flash
- Other flashes in environment can trigger false readings
Cumulative Flash Metering
Some meters can accumulate multiple pops of flash to measure total output.
Use for:
- Measuring multiple flash heads simultaneously
- Getting more precise readings
- Testing consistency between pops
Reading the Meter
Understanding the Display
Most meters show:
- Aperture (primary reading)
- Shutter speed (set by you for sync)
- ISO (set by you)
- EV (exposure value)
Example reading: ISO 100, 1/125s, meter shows f/11
This means: at ISO 100 with shutter at 1/125s (your sync speed), shoot at f/11.
EV Values
This section explains the mathematical basis of exposure values. It's useful for understanding, but not required for practical studio work. Skip to "Measuring Lighting Ratios" if you want to focus on technique.
Exposure Value (EV) is a single number representing a combination of aperture and shutter speed.
Understanding EV:
- EV 0 = 1 second at f/1 at ISO 100
- Each +1 EV = 1 stop brighter
- EV 15 = bright daylight
- EV 10 = typical studio flash
Why EV matters: EV makes it easy to compare light intensity regardless of your aperture/shutter choice. A light metered at EV 12 is one stop brighter than EV 11.
Converting Readings
If your meter shows f/11 but you want to shoot at f/8:
- f/8 is one stop more exposure than f/11
- You'll overexpose by one stop at f/8
If you need f/8, adjust flash power down one stop.
Measuring Lighting Ratios
Ratios compare the brightness of different parts of your lighting setup.
Key-to-Fill Ratio
The most important ratio in portraiture.
Measuring method:
Turn on only the key light.
Meter at subject position, dome toward camera. Note reading.
Turn off key, turn on only fill light.
Meter at same position. Note reading.
Calculate difference in stops.
Interpreting the difference:
| Key Reading | Fill Reading | Difference | Ratio |
|---|---|---|---|
| f/11 | f/8 | 1 stop | 2:1 |
| f/11 | f/5.6 | 2 stops | 4:1 |
| f/11 | f/4 | 3 stops | 8:1 |
Setting a ratio: If you want 3:1 ratio (1.5 stops):
- Key at f/11
- Fill at f/6.3 (between f/5.6 and f/8)
Measuring with Combined Lights
Alternative method:
Meter lit side (key + fill): e.g., f/11
Meter shadow side (fill only—block key with your body): e.g., f/5.6
Difference is 2 stops = 4:1 ratio
Hair Light and Background
Measure these independently:
Hair light:
- Meter at top of subject's head, dome pointing up at hair light
- Typically 0.5-1 stop over key reading for visible highlight
- Too bright = blown hair, too dim = no effect
Background:
- Meter at background surface
- Brighter than key = high-key, white background
- Equal to key = grey background
- Darker than key = darker background
- No background light = may go black
Advanced: Applying Zone System to Studio Work
This section applies Zone System principles to studio photography. If you're new to studio work, focus on the basic metering workflow above first. Return here once you're comfortable with standard incident metering.
The Zone System applies to studio work, especially for precise tone placement.
Placing Tones
Zone V = middle grey (18% grey card)
- Incident meter reading places subject midtones at Zone V
Zone III = dark but detailed
- 2 stops below meter reading
Zone VII = bright but detailed
- 2 stops above meter reading
Studio Zone System Method
Place a grey card at subject position.
Meter (incident) at grey card, dome toward camera.
Shoot at metered exposure—grey card will be Zone V.
Adjust lights or exposure to place other tones where you want them.
Previsualization
With controlled lighting, you can plan exact tone rendering:
- White shirt: Zone VII (2 stops over meter reading)
- Skin tone: Zone VI (1 stop over meter reading)
- Dark suit: Zone III (2 stops under meter reading)
Set exposure for skin (Zone VI), then adjust overall lighting until white shirt and suit fall where you want.
Working Without a Meter
If you don't have a light meter, there are alternatives.
Polaroid/Instant Testing
Traditional method:
Shoot instant film at your estimated settings.
Evaluate the result.
Adjust and test again until correct.
Modern instant options:
- Instax Mini/Wide/Square
- Instant backs for medium format (rare, expensive)
- Polaroid 600/i-Type (limited ISO options)
Limitations:
- Instant film ISO may not match your film
- Requires adjustment calculation
- Adds cost per test
Digital Camera as Meter
Very practical modern approach:
Set digital camera to same ISO you'll use on film.
Shoot test frame.
Evaluate histogram and image.
Adjust settings and repeat.
Transfer settings to film camera.
Advantages:
- Immediate feedback
- Can evaluate lighting, composition, expression
- Histogram shows exact exposure
Limitations:
- Requires digital camera
- Dynamic range differs from film
- Colour rendition differs from film
Guide Number Calculations
When all else fails, calculate from flash specifications:
GN = Aperture × Distance (ISO 100)
Example: Flash GN 40, subject at 3m, ISO 100: 40 ÷ 3 = f/13 ≈ f/13 (between f/11 and f/16)
Account for modifier losses (softbox loses ~2 stops).
Metering for Film Specifically
Exposure Latitude Considerations
Negative film (colour and B&W):
- Has latitude (especially for overexposure)
- If uncertain, round up (more exposure)
- "Expose for shadows, develop for highlights"
Slide film:
- Minimal latitude
- If uncertain, round down (protect highlights)
- Meter carefully and consider bracketing
Bracketing Strategy
Even with careful metering, bracketing provides insurance:
For critical work:
- Meter reading (correct exposure)
- +0.5 stop
- -0.5 stop
For slide film:
- Meter reading
- +0.3 stop
- -0.3 stop
For testing new setup:
- Full stop brackets: -1, meter, +1
Push/Pull Adjustments
If you know you'll push or pull process, adjust your metering:
Pushing:
- Rate film at higher ISO on meter
- Example: Push HP5 2 stops → meter at ISO 1600
Pulling:
- Rate film at lower ISO on meter
- Example: Pull Tri-X 1 stop → meter at ISO 200
Practical Metering Workflow
Single Light Setup
Set meter to flash mode, ISO to your film, shutter to sync speed.
Position at subject, dome toward light.
Fire flash, note aperture.
Set camera to that aperture.
Shoot.
Multi-Light Setup
Meter key light alone (all others off).
Meter fill light alone.
Adjust power/distance to achieve desired ratio.
Meter all lights together for final exposure.
Set camera, shoot.
Continuous Light
Same principles, but use ambient mode:
Set meter to ambient mode, ISO to your film.
Position at subject, dome toward camera (or light).
Take reading, note aperture/shutter combination.
Set camera, shoot.
Common Metering Mistakes
Forgetting to Reset ISO
Meter set to wrong ISO gives wrong reading. Double-check ISO setting before metering.
Metering with Wrong Dome Position
- Dome toward camera: measures all lights, gives overall exposure
- Dome toward light: measures that light only
Know which you're doing and why.
Not Accounting for Falloff
If you meter at subject's face but they lean back, they receive less light. Re-meter when subject position changes.
Assuming Meter is Perfect
Meters are calibrated to expose middle grey as middle grey. If your subject is lighter or darker overall, adjust:
- Very light subject: may want to overexpose slightly from meter reading
- Very dark subject: may want to underexpose slightly from meter reading
Summary
- Incident metering (dome toward camera) is standard for studio work
- Flash meters capture the brief burst; use sync cord or cordless mode
- Ratios are measured by metering each light independently
- Zone System applies in studio—place tones precisely
- Digital test shots can substitute for light meters
- Negative film tolerates overexposure; slide film needs precision
- Check your settings (ISO, sync speed) before each metering session
A light meter is an investment that pays off in reduced wasted film and increased consistency. Understanding how to use it properly makes studio work predictable and repeatable. Master metering and you control your lighting precisely.