How Accurate Are Handheld Light Meter For Photography

By | 24/09/2022

The New York Institute of Photography is one of the world’due south largest photography schools and because we are, we often publish fun and useful photography tips on our photography weblog. Delight enjoy!

We recently received an e-mail from a student who was struggling to understand the difference between in-photographic camera and handheld low-cal metering.

For starters, it’s important to understand that there are two dissimilar ways to mensurate light in order to achieve a properly exposed paradigm. You tin can measure the light reflected by the subject, which is how the calorie-free meter in your camera works, or you lot can mensurate the calorie-free falling on the subject (which nosotros too phone call incident light metering) using a handheld light meter at the subject position.

An important factor to understand is that meters are calibrated to mensurate a neutral grayness tone. A reflected light meter “assumes” that the subject field is reflecting the same amount of light equally a Gray Card would reflect. However, if the subject area is bright white and shiny or black with a non-reflective matte terminate, the meter will requite a simulated reading which the photographer volition then have to correct.

For simplicity, the following examples only mention opening or closing the aperture, but you could achieve similar results by changing ISO and/or selecting a different shutter speed.

With the camera’southward reflected light meter, if the subject is bright white the lensman must select an discontinuity approximately 2 stops larger than the meter indicates. That’s because the camera “thinks” it’s looking at neutral grey, non bright white, and so information technology’s going to indicate an discontinuity which volition expose the scene as gray, not white. Imagine photographing a snowy winter scene in brilliant sunlight, or white sand dunes in the Sahara. If the camera’southward meter indicates f/16 every bit the correct discontinuity, y’all may have to open the aperture to f/8 to get the snow to await white instead of grayness. However if you are using a handheld incident low-cal meter, it should give y’all an accurate reading of the vivid sunlight illuminating the scene, and no adjustment will be required. The incident light meter should point f/8 in the aforementioned state of affairs where the camera’s meter might point f/16. That’s considering it’due south reading the sunlight straight, not the light reflected by the bailiwick.

If you are photographing a darker-than-neutral gray subject field – for instance a black comport in night, deeply shaded woods – the camera’south meter may give you a reading that will overexpose the subject. That’due south because black bears reflect less calorie-free than a Grey Carte, but the camera still “thinks” the scene is a neutral gray shade. So if the camera’south meter indicates f/two.8, you lot may accept to select an aperture of f/five.half dozen instead to get a properly exposed paradigm. Again, a handheld photographic camera should requite you an accurate reading of f/5.half-dozen because it doesn’t intendance virtually the subject’s tonal value or reflectivity, only the value of the light illuminating the subject.

The aforementioned principles hold true with portraiture. A light-skinned blonde helpmate in a white wedding clothes posed in sunlight with a brilliant-white wall behind her volition probably be metered incorrectly (underexposed) past the camera’s reflected calorie-free meter while a dark skinned groom in a black tuxedo posed confronting a black curtain volition likely exist incorrectly metered (overexposed) by the camera. The photographer should sympathise this and increase or decrease exposure appropriately if they are relying on the camera’s meter, or use a handheld incident lite meter for more accurate results.

In-camera metering can exist further complicated depending on the metering mode the photographer chooses. Spot Metering will have a reading from a small “dot” in the frame. Average Metering, including Center Weighted Average and Matrix (Nikon) or Evaluative (Canon) modes will measure light from the total frame and average out the bright and night areas. The class text in Lesson 2.3 suggests Spot Metering from the subject’due south cheek, but below the centre, so you are exposing the image for the best skin tones.

One more note – either meter normally reads only the ambience “constant” light. Yous demand a meter with Flash Metering capability to measure the instantaneous burst of light from a wink or strobe.

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Originally posted 2022-02-12 17:26:41.