Your iPhone is a Light Meter, Waveform Monitor, and False-Color Display with $5 Cine Meter App

Talk about your digital leatherman: The number of ridiculously handy -- and practical, and portable, all in one -- apps for filmmaking on mobile devices is probably one of the greatest tech-vantages we've got going for us these days second to low-cost high-res acquisition. Uses range from lighting plot diagramming and shooting scheduling all the way to Canon DSLR control via Android and RED control via iOS -- there's an app for all that, and more. Now, thanks to Adam Wilt of Pro Video Coalition (and a lot of other great stuff), your iPhone is now more of an asset on set than ever before -- and that's because his new $5 app Cine Meter turns your iOS device into a light meter, waveform monitor and false-color display.

There don't appear to be any videos of Cine Meter in action just yet, but Adam has included a load of technical info on his site:

See the light: Cine Meter not only gives you exposure information, it shows you at a glance how evenly your greenscreen is lit, and where high-contrast hotspots and shadows may give you trouble. With Cine Meter, you can walk around, light your set, and solve problems long before your real camera is set up, making pictures, and running down its batteries.

  • The light meter shows you the stop to set as decimal readings (such as f/5.0, good for cameras with EVF iris readouts) or full stops and fractions (like f/4.0 ⅔, good for cine lenses with marked iris rings). You can calibrate Cine Meter to match other meters to a tenth of a stop, and take readings using matrix or spot metering.
  • The waveform monitor shows you how light levels vary within and across a scene. They show you how even the lighting is on a greenscreen or white cove, and let you see hotspots and imbalances at a glance. The waveform’s RGB mode shows you color imbalances in the image and gives you a handy way to check for color purity on a greenscreen or bluescreen.
  • The false-color picture lets you define allowable contrast ranges, and see instantly which shadows are underexposed and what highlights risk clipping:

Limitations of Functionality:

Here's Adam with additional details on how the app works, which is contingent on the ways iOS does or does not allow apps to use to use onboard cameras:

Cine Meter can only do what an iDevice (iPhone / iPad / iPod touch) lets apps do: lock and unlock exposure and white balance, but not preset either one to a known value; and read out scene brightness values. These limitations define what Cine Meter can -- and can’t -- do.

  • The light meter is absolute -- you can count on its readings to mean what they say, regardless of circumstance, since they’re calculated from the camera’s reported brightness value. Once you calibrate Cine Meter to your reference standard, it should always give you correct readings.
  • However, the picture, false-color picture, and waveform monitor displays are only relative—they show scene brightness values relative to other levels in the scene, but the levels of those images and waveforms depend on how the camera sets its exposure, which often differs from the brightness value the camera reports to the light meter, as described in How It Works
  • For this reason, you can’t directly compare light meter readings with waveform or false-color levels!
  • You can’t preset an exposure level or a white balance and then use the displays to show you absolute levels. iPhone / iPad / iPod touch cameras don’t let you manually preset values; they only let you lock in the current auto-exposure or auto-white-balance setting, so you can’t set the scopes for, say, ISO 800 @ 1/48 sec @ f/4.0 with a color temperature of 3200K.
  • The only way to set a particular exposure level is to trick the camera by showing it the “correct” light (for example, using a gray card) and then locking its settings. Once locked, you can then look at the pictorial displays to see how tones and colors in a scene render relative to the locked settings.

That’s the key to getting the most out of Cine Meter: treat it like a point-and-shoot camera with exposure and white-balance locks (which is really what it is, only with fancier readouts), and you’ll be able to “fool” it into doing what you need.

This is a lot like the way you used to have to fool older Nikon DSLRs into the desired exposure for shooting video, but much more understandable here -- it's only a phone (or pad, or pod) after all. That said, this app seems to put practical functionality into your iPhone that's a heck of a lot more practical than, say, trying to shoot a film on one. It's not going to be perfect, and shouldn't outright replace a dedicated professional light meter -- or the waveform readout you would get from your A camera in proper placement, for that matter -- but it's a heck of a start. As such, it's a tradeoff, but one in which you get serious value out of $5, a bonus when compared to the tag attached to pro meters (or waveform monitors!). I can see a lot of qualitative mileage out of this little bag of tricks in the right hands -- which, of course, are your hands given skillful usage.

You can check out Adam's site for the full details -- an Android version is coming, by the way.

In the meantime, what are you iOS users waiting for -- I can't try it out for myself (yet, at least), so let us know about your experiences with Cine Meter in the comments below!


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Your Comment


"an Android version is coming, by the way"

January 24, 2013 at 12:47AM, Edited September 4, 8:21AM


Who is going to trust this on anything that matters?

You could shoot your film on your iphone to, doesn't mean you should.

January 24, 2013 at 1:34AM, Edited September 4, 8:21AM

Fresno Bob


January 24, 2013 at 5:45AM, Edited September 4, 8:21AM


* People who don't have a light meter and would rather spend their limited money on something else.

* People who don't have a monitor with waveform and want to see if their green screen is evenly lit.

* People who have a very nice light meter and camera but left them at home. I often find myself discovering a nice location, then wondering if it's bright enough me to come back and shoot with available light only. I'm used to taking stills with my phone in these situations, to analyze them and try to guess how much light there was there. This app is a huge improvement on that.

January 24, 2013 at 6:10AM, Edited September 4, 8:21AM


This. While it looks neat, I wouldn't trust this thing any farther than I could throw it. Show me some side-by-side tests with actual legitimate testing equipment, and then I might be a little more convinced.

Maybe next time we can get a buyer's guide for an actual light meter?

January 24, 2013 at 6:37AM, Edited September 4, 8:21AM


I paid the $5 for the Cine Meter app and tried it out, initially it does seem very cool and useful for general reference or emergency backup. If it's w/in 15% of accurate, completely awesome for a phone app I have with me at all times anyways. I'll try to find time this weekend to do some tests/calibrations/comparisons with a RED, Sekonic Cine meter/scope, charts/cards, and some Zeiss primes. If the planets align, I'll report back. Thanks

January 24, 2013 at 7:13PM, Edited September 4, 8:21AM


Cool! I just bought it! Will be testing it on my next project.

January 24, 2013 at 1:43AM, Edited September 4, 8:21AM


great idea, I hope that sekonic or gossen or kenko pick up on it.

January 24, 2013 at 6:32AM, Edited September 4, 8:21AM


My friend told me about this last night; downloaded and said he would be able to test it out soon. It sounds like a good app to have, along with Dale Grahn Color. I'll look for my friend's blessing because I don't own an iPad.

January 24, 2013 at 6:45AM, Edited September 4, 8:21AM


Now this is useless... unless you can plug in a feed from the camera you're using (or you're going to *shudder* shoot something on the iPhone).

January 24, 2013 at 9:23AM, Edited September 4, 8:21AM


Wow there's a lot of cynicism here on this post which in my opinion is a refreshing change for nofilmschool.

It's an app that costs $5. Let me repeat that, FIVE DOLLARS. Come on people, a block of cheese costs more than that. Based on many, many other posts and comments throughout this site over the last few months, many of you seem quite happy to pay $3000 plus for a camera you've never seen or been able to test in the field and yet you're clamoring about a $5 app?

January 24, 2013 at 10:46AM, Edited September 4, 8:21AM


Agreed. I have a "real" light meter. And a "real" color meter too. But they're not always in my pocket. My phone is. If one were to trust a $5 app for shooting a reel of 35mm film with no other light tools, yeah. That would be crazy. But we have monitors (sweet!) and metering BEFORE setting up the camera is a good idea. This should get someone 90% there.

January 24, 2013 at 1:53PM, Edited September 4, 8:21AM

Erik Stenbakken

Thanks - I'll use the block of cheese as my meter - at least when it doesn't work properly I can eat it.

January 25, 2013 at 9:00AM, Edited September 4, 8:21AM


I just downloaded this app on the idea that it would be worth it to have a back up in case my Sekonic fails at the wrong moment. I figured I would test it against the real meter to see if it can be trusted. Oops, just wasted $5. This does not function as an incident meter, only as a reflected meter. That is - it measures what the camera sees, not the amount of light hitting the camera/sensor. With spot meter "off" it measure the whole camera field of view. With spot meter "on" it measures a rectangle about 15° across (w/iPhone 4s). My Sekonic spot meter measures a 1° circle. So there's no real way to test it against a real meter. I'm sure this app is good for a number of things, just not as an emergency meter backup as I was hoping.

January 24, 2013 at 10:45PM, Edited September 4, 8:21AM


Please take a look at iZoner.
The next upcoming release will contain also an incident meter.

January 28, 2013 at 3:10AM, Edited September 4, 8:21AM


what i like about this is if needed, i can match it to my sekonic and give my phone to my gaffer or anybody else and let them get a much better feel for whats going on rather than just guessing. Im gonna test it with my sekonic and see how it works.

February 3, 2013 at 10:44AM, Edited September 4, 8:21AM

domenic barbero

Having read this I thought it was very enlightening.

I appreciatte you finding the time and energy to put
this information together. I once again find myself personally
spending a lot of time both reading and leaving comments.
But so what, itt wass still worth it!

August 4, 2014 at 9:15AM, Edited September 4, 8:56AM


Thanks Patrick I had a chuckle at this... bwah ha ha ha haaaaar.

April 26, 2015 at 3:20AM, Edited April 26, 3:20AM

Paul Abrahams