Cell phone light meter app

Discussion in 'Accessories' started by davidspahr, Dec 22, 2020.

  1. Has anyone tried one of the light meter apps on their cell phone?
    How has it worked for you and what did or didn't you like about it?

    My Canon EOS T5 has a builtin light meter, but I'm thinking of something
    for my Canon AE-1 and TX film cameras.

    Thanks. Merry Christmas to all.
  2. I don't think there is a good substitute for a stand-alone light meter for accurate results. I use a Sekonic spot/incident/flash meter.

    However I bought a Lumu color meter which plugs into an iPhone. It doesn't seem to be absolutely accurate under a CRI 95 light source, but it is consistent. I use it for matching adjustable LED panel lights with ambient and each other. The most accurate method is to use a standard grey card sometime during the shoot. RAW image don't have a certain white balance, so the grey card help in post. A real color meter costs $1500 or more, compared to $300 for the Lumu.
    Last edited: Dec 22, 2020
  3. The free LightMeter app works quite well on my Android phone, but I suspect it might be device dependent.

    The incident metering mode obviously isn't going to be as good as a handheld meter, because it doesn't have a diffusing dome, but the reflective metering is probably more accurate than a wide-angle handheld meter.
    Surely the RGB histograms on almost any digital camera can do that? Maybe not as fast as a colour-meter, but certainly a lot cheaper.

    I'm also seeing digital Luxmeters for sale at well under £50 UK, while the cheapest photographic light meter is priced about 4 times higher.
    Another case of "let's rip off those rich photographers"?
  4. Cameras do very well adjusting thier white balance, but they suffer when faced with mixed light sources. I use the Lumu to match light sources. I'm using LED light panels with adjustable color, between 3200K and 5500K. It's also a lot easier to compare numbers than shapes, especially when you can't display both histograms at the same time.
  5. SCL


    I've been testing one out on my Iphone. It seems accurate compared to my Gossen, but it is still to early in use to give it a definite thumbs up. FWIW the two things which are a negative for me is that if there is light shining on the screen I'm trying to read, it becomes unreadable, unlike a handheld meter, and it doesn't have an incident dome reading.
  6. That's exactly what I thought.

    The custom WB on my Sony MILCs tells you the CT that's been read from a grey or white card exposure, along with any magenta-green tint.
    Wouldn't that be just as useful as a colour meter reading?

    Like I said, a bit slower to do, but effectively 'free' as opposed to the quite high cost of a separate colour meter.

    I think for most photographers, the number of times a colour meter is genuinely needed makes the cost of purchase uneconomical.
    Last edited: Dec 24, 2020
  7. Yes, I am installing some app on all my Android devices. - Available apps varied. Sorry, I have no real results to show. I do benefit from the app(s) by evaluating environments on a photography dry swimming / planning stage.
    My devices' lack of strap lugs makes the app feel like a cumbersome substitute for a purpose built light meter; not even mentioning the time needed to wake up a device start the app and get settings right for your needs.
    You didn't tell what film you'll be using and I am not familiar with a TX. - AE-1 and negative film I'd use with the built in meter. How does that camera work without battery? 1/125 sec & B to choose from?
    davidspahr likes this.
  8. I'm not saying a color meter is for everyone, much less one which costs $1500 or more. Not many photographers will take the time and effort to set up continuous lights. Notable exceptions are in the studio and for videography. For everything else, automatic white balance (AWB) keeps us fat, dumb and happy.

    If the lighting is consistent, setting against a grey card is probably the best solution, but it doesn't always work if the lighting is mixed. In particular, highlights and shadows on faces may be noticeably different. It's more than "a bit slower" to carry a camera and grey card to set up each light. Professional video cameras may sprout enough cables to resemble a Greek Medusa. If there is a dominant color in a scene, along with people, a color meter or grey card is essential to render faces correctly. Most photographers find it "a bit" easier to use the eyedropper in post on a neutral colored object in the scene. If there is such a thing, I haven't found one unless I bring one along, a matte, 10"x8" card by Gretag-MacBeth.

    Video is less forgiving of the light. Many cameras have 8-bit color depth, which can result in noise and posterization when corrected in post. More cameras now have 10, even 12 bit color. That's still a far cry from 14-16 bit still cameras. Plus there's no "post production" for live-streaming. It takes me 1-2 hours to setup with audio, and another hour for live streaming. Any time saved during or after the shoot is welcome,

    The Lumu also serves as a conventional, incident light meter, and can be. used for flash readings (including color).
  9. I think it is highly device dependant.

    I tried an app on my Alcatel Pop 4+ (TCL 5056) and it was hopeless in lower light levels, exactly the sort of conditions when I needed a light meter.

    That said, the camera on my phone is pretty poor too, I suspect the two are closely linked.

    It costs nothing to try, but you need something to evaluate it against, unless it's as away with the faeries as mine was...
  10. The TX is a variation of the Canon fTb, introduced just before the AE-1. The shutter and aperture are strictly mechanical and you select them as you please,
    There is a photocell light meter, but it is only for reference.
    With the AE-1, dead battery, dead camera.
  11. Thanks for the comments. I don't do any studio photography. I was just curious about using a cellphone for a light meter
    During my Thanksgiving trip, I saw a gal taking pictures and it looked like she was using her cellphone for a light meter.
    Didn't think to ask her.
  12. This is a screenshot of the free app I'm using.
    It's actually a lot more useful than any 'retro' handheld meter. The hub of the dial turns into a spot-metering viewer in reflective mode, making it more accurate than an old wide-field handheld meter.

    Given the choice between an old reflective selenium-cell meter and the phone app; I think I'd pick the phone app every time.
    davidspahr likes this.
  13. Thanks. I'll give it try.
  14. Just for laughs: I installed "Light Meter-Free" on 2 different tablets. Lenovo suggests 1/40 sec, Samsung at least 1/640 for same ISO f-stop etc.
  15. I bet it was the Samsung that was a country mile out. They just seem unable to stop themselves messing about with their flavour of Android to render it useless beyond the basics.

    Last edited: Jan 30, 2021

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