This app was mentioned in 3 comments, with an average of 2.00 upvotes
Dare I say, there's an app for that
Obviously not NIST traceable, but would suffice for relative comparisons.
There is this light meter app . I have not used it, just remembered reading about it on Houseplant Journal.
edit: for android phones
What app?
and Light Meter on Android
Are these the apps you're talking about? Looks like one only measures lux and the other doesn't have a good description so without an iphone i dunno.