KelvinCam is a light meter and color temperature meter for iPhone and iPad. It reads Kelvin, tint, exposure and lux live through your camera, so color and exposure are right in camera, not fixed in post. Made for photographers, filmmakers and anyone lighting a scene.
Free to download · Pro $9.99, once · no subscription · iOS 18 or later · ready for iOS 27
Point your iPhone at the scene: an outdoor shoot as the sun moves, a room in mixed light, a set you're lighting. KelvinCam reads the light the way a handheld meter and a color meter would, and keeps updating as the light changes. It reads the light reflected from the scene, as your camera does; here's how that differs from an incident light meter.
Set Kelvin in camera before you roll, outdoors as the light shifts or indoors in mixed light, so shots match without fixing color in post. KelvinCam applies the 180° shutter rule at 24 to 120 fps, or any rate you type, and tells you when you need an ND filter.
Choose your stock, from Portra and HP5 Plus to Tri-X, and KelvinCam pins ISO to box speed and corrects long exposures for reciprocity failure, with notes on each stock's character.
Spot-meter the key light and mark it, then meter the fill. KelvinCam reads the ratio in stops, so you can set exactly the contrast you want, from flat and even to deep and dramatic.
Open a live luma histogram. Clipping warnings show when highlights blow out or shadows crush, and how much of the frame is affected.
Download it and keep using it. No time limit.
One in-app purchase. Yours to keep. For comparison, a handheld pro light meter typically costs $200 to $500.
Try every Pro tool free for 20 minutes first, once, with no card and nothing to cancel. $9.99 is the US price; the App Store shows the price in your currency. Reinstalled, or on a new device? Tap Restore Purchase.
For most shoots, yes: KelvinCam gives fast, consistent readings of color temperature and exposure. A phone camera isn't a calibrated instrument, though, so if you own a handheld meter, KelvinCam Pro lets you calibrate against it with offsets for EV (up to 3 stops), color temperature (up to 500 K) and tint, and shows raw and calibrated readings side by side. If you need precise lux numbers, an incident meter app is the better tool; see how KelvinCam compares with Light Meter LM-3000.
Color temperature, measured in Kelvin, describes how warm or cool light is. Candlelight is around 1,900 K, midday daylight around 5,600 K, and shade or an overcast sky runs cooler, often 6,500 K or more. White balance is the camera setting that corrects for it. KelvinCam measures the first so you can set the second, in camera, before you shoot.
No. KelvinCam is free to download and use. KelvinCam Pro is a single in-app purchase ($9.99 in the US) with no subscription and no account. If you reinstall or get a new device, tap Restore Purchase.
Yes. You can try every Pro tool free for 20 minutes, once, with no card required.
iPhone and iPad with iOS 18 or later. The on-device lighting assistant needs an iPhone with Apple Intelligence.
Yes. The free version meters any scene and lets you lock ISO to your film's speed. With Pro, pick your stock and KelvinCam fixes ISO to box speed and corrects long exposures for reciprocity failure.
Email support@rivotlabs.com. We answer every email personally.