LightSpectrum Pro

I think some of the reviewers of this product don’t know what color temperature is. It has nothing to do with brightness. The reviewer who suggested measuring the light reflected off a piece of white paper is giving great advice. If you do that, the app seems reasonably accurate when measuring light above 2700K. It is NOT accurate below that color temperature. It thinks an amber light is still 2700K. For the price, I think it is worth 3 stars. Disclaimers: I did not compare measurements against a professional meter, and I’m using an iPhone 7.

This app can save you $1,600 USD. That is the cost of a professional Sekonic C-800 color meter. I’ve tested this app, extensively, in multiple lighting conditions and it’s never been off by more than ~100 kelvin. Most professional DSLR and MILC cameras only allow setting custom white balance in 100 kelvin increments anyway, so this app’s margin of error is very well within the acceptable range. The closest that this app was to reference was a stunning 14 kelvin! Virtually all of the other reviewers, unfortunately, have been using and testing this app incorrectly. (Certainly this app’s documentation could be improved). This app is not an incident color meter like the C-800, so you can’t just dangle it in the air and expect an accurate reading. To get an accurate reading with this app you have to point your iPhone’s camera at an RGB-neutral white or gray target—IN EVEN LIGHTING—(like the X-Rite Color Checker Passport’s white balance card, for example). This should give you a reading that’s within approximately 100 kelvin from the reading you’d get from an extraordinarily expensive handheld incident color meter. I use this app to calculate the delta between the white balances of ambient lighting and flash lighting in order to precisely determine how to gel the flashes, without guessing and without having to use a $1,600 color meter.

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The description really should say which devices this app works on. It doesn’t work on an iPhone 11 (the numbers don’t change at all), but it does work on an older iPhone 6s that I happen to still have.

I shoot indoor sports in a variety of poor lighting. High school gyms. This app was recommended by another pro photographer and it has proven to be very helpful. While I shoot in raw, it’s nice to get the white balance correct in camera as a starting point for editing. This app does that. I especially appreciate the spectrum display which helps me understand what’s behind the K value. For sure worth its small cost!

And I love it. Easy to use and makes locking white balance in manual mode camera apps a breeze!