In one of the previous blog post on IDA, we discussed different metering modes and their uses. Metering modes are a good way to read the light in a frame and can be a tremendous help in setting correct exposure for a frame but, metering modes are also prone to make mistakes in tricky lighting situations. They often don’t work as per your expectations when you plan to use different sorts of flash lights. A light meter calculates the reflected, incident or flash light and gives a reading based on which one can decide to set the camera aperture and shutter speed in order to shoot a correctly exposed image. ISO values can be fed to a light meter which later combines the light measurement with it and suggests the aperture and shutter speed values. The photographer can either use those values or can shoot an under-exposed or over-exposed image on purpose.
A light meter can work in different modes and some important modes amongst them are:
1. Reflected Mode
Light meters in this mode work on similar principal as that of a DSLR’s metering mode. They read and measure the reflected light from the subject. These light meters can be placed near the camera and the light getting reflected from the scene will be captured and measured there. These light meters also have the same pitfall as the camera’s metering mode. They can be fooled when a subject reflects a lot of light. In those cases, the image becomes under-exposed as the suggested exposure by these light meters can be under-graded.
2. Incident Mode
In Incident mode, light meters measure the light which falls on the scene or the subject. They can be more accurate than the reflected mode metering as the incident light remains constant in the whole area it is falling onto. The light falls on the lens through a hemispherical dome and gets measured. In this mode, the light meter has to be kept near the subject to measure the light. For example, to measure the light falling on the face of the subject for portrait photography, the light meter needs to be placed near subject’s face to acquire the reading. If multiple light sources are projecting lights from different sides using incident light meters, multiples readings can be taken at different places and their average can be calculated for the correct exposure.
This mode isn’t suitable for a landscape photo-shoot as the focus in landscape goes up to infinite distance and holding the light meter everywhere is practically not possible.
3. Spot Mode
In spot mode, light meter works in similar fashion as the spot metering mode of the camera. It reads the reflected light like reflecting light meter but at a very small angle. This angle comes in a range of 0.5% of the total scene which can be used very effectively for high contrast situations. Using the spot meters, multiple readings of bright and shadow areas of the same scene can be taken and the values can be calibrated to their average for better results.
4. Flash Mode
Synching a light meter with a strobe or a flash gun can be done easily using radio or wireless transmitters. The light meter measures the flash light and suggests the camera settings based on its reading. This can be used very efficiently while shooting in a studio or places where off-camera flashes are used to light the subject.
How to use a light meter
The light meter will take the reading and suggest you the camera settings accordingly. In incident mode, the reading can be taken around the subject or the subject itself can hold it around his or her face pointing the dome towards the lighting source and get the reading. The same process can be executed while using the flash. If multiple flashes or light sources are being used, you have to take the multiple readings and calibrate them to find the average. The meter will suggest the camera settings based on the average value.
Light meters are an immense help in professional photography. In studio, where the photographer needs a lot of control over his lighting, these meters have proven most conducive. However, in landscape or wildlife photography where the incident mode cannot be used (unless you choose to walk around a tiger’s face with a light meter in your hand), the camera metering modes work as good as the reflecting mode of light meters.
The price of light meter can impact your decision to buy one, but nevertheless, they can surely be efficient in providing more accurate light readings. It is suggested that before buying them, you make yourself comfortable with different metering modes of your camera and only when you feel the need of a light meter to express your desire for a better light reading, you should opt for a light meter.