Pocket Light Meter App for iPhone

My light meter of choice for close to two decades has been the Pentax Digital Spot. My first act when setting out into the landscape to photograph with my old 4×5 view camera was invariably to hang the pistol-gripped device around my neck. It went everywhere with me, and determining exposures with it, including filter factors, reciprocity failure of film, and camera bellows extension became second nature.

Though today’s digital cameras make hand-held meters unnecessary for most landscape photography, from time to time I still encounter situations when it would be handy to be able to take a meter reading independent of the camera. Incredibly, the iPhone delivers a solution that is very practical, effective, and free!

Nuwaste Studios has developed a spectacular light meter app for iPhones. It will read down to EV -1.78 and can be used to calculate accurate exposures longer than you would ever need (hundreds of hours). It can be calibrated as well if necessary, though in comparison to both my Pentax meter and my Nikon D700, it is right on the money. The correction factor comes in really handy, however, for film users who need to account for filter factors or reciprocity failure. In addition to shutter speed and aperture, it also reads out in EV, Lux, Foot Candles, and Cine shutter speeds. If this were a stand-alone digital light meter, it would cost $200 or more.

The next time I need to do an exposure longer than 30 seconds, or if I’ve got my camera all locked down on the tripod and don’t want to move it to take an in-camera meter reading, I’ll just grab my iPhone! –Justin Black

Download here: Pocket Light Meter by Nuwaste Studios


3 Responses to “Pocket Light Meter App for iPhone”

  1. Ashley said: on August 15th, 2011 at 12:42 pm

    I downloaded this app because I need to be able to read foot candles in different light settings for work. However the foot candle reading from this app and the foot candle reading I get from my actual light meter are drastically different. Any idea what I’m doing wrong?

  2. Justin Black said: on August 18th, 2011 at 2:29 pm

    Hi Ashley, I just checked the lux and footcandles readings from the app on my iPhone 4 against a few different Lux-Foot Candle calculators and conversion charts, and it appears very accurate. You might take a look at this chart from light meter manufacturer Sekonic, and see how it compares to the readings you are getting from both your meter and iPhone: Sekonic EV-Lux-Foot Candle Chart http://www.sekonic.com/Support/EVLuxFootCandleConversionChart.aspx

  3. Frank Wylie said: on June 28th, 2012 at 6:43 pm

    Unfortunately, the app has been modified to remove the footcandle readings, so unless you use the ftc conversion charts in conjunction with the app, it no longer can supply direct ftc readings.


    “This version, controversially, disables conversion of the exposure value to approximation of illuminance in lux (lx) and Candle*feet. This is done because previous estimates weren’t good enough. Lux and candle*feet are measures of illuminance (how much light is falling on the object) and a camera cannot measure that. Any and every camera in the world captures light reflected from objects, not the light falling on objects.

    We had to remove those measurements, because people were using them incorrectly and were relying on wrong measurements when making judgements for emergency lighting installations and other stuff that we don’t want to be held responsible for.”