Accurate exposure is critical in product photography, and understanding light metering is key to achieving it. When working with flash, the built-in metering systems in cameras can often be inadequate, easily fooled by reflective objects or extreme light and dark scenes. This is where a dedicated light meter comes into play.
Understanding Through the Lens (TTL) Metering and Manual Flash
TTL metering is a feature found in many cameras where the camera uses pre-flash signals to determine the correct exposure. It factors in both ambient lighting and flash. While this can be convenient, TTL flashes tend to be more expensive than manual flashes, also known as “dumb flashes.” Moreover, the cost can skyrocket when multiple TTL flash modules are needed. On the other hand, manual speedlights and strobes are more cost-efficient but can require more guesswork to get the desired settings. This is where light meters shine, helping you achieve the correct exposure without the guesswork1.
Reflective Metering vs. Incident Metering
Light meters offer incident light metering, which is often more accurate for product shots. Here’s why:
- Reflective Metering determines the relative intensity of light bouncing off a subject. It’s what your camera’s built-in metering system uses.
- Incident Metering determines the relative intensity of light falling on a subject.
The advantage of incident metering is that it’s not influenced by the reflectiveness of the subject. It only cares about the amount of light falling on the subject. Plus, it can meter the flash, something reflective metering can’t do. This makes incident metering more accurate and reliable for product photography1.
Using a Light Meter
A light meter, when placed in flash metering mode, waits for a flash input, then responds with the measurement of that flash pulse. To get the basic exposure, you compose your scene, turn on the light meter, and set it to flash metering mode. You then adjust your camera settings according to the light meter’s readings. The light meter will give you an F-number, which is the appropriate aperture for good exposure given the readings from your light meter.
Understanding and utilizing a light meter can dramatically improve the quality of your product shots by ensuring that your images are correctly exposed every time. It’s an invaluable tool that can help you navigate the complexities of light in photography, ultimately enabling you to produce more professional and appealing product photos.
