I haven’t tested it with Zak’s app yet, so I’m interested as to what you’ll find…The caveat is that you’d need a calibrated/verified light to calibrate to, hypothetically you could set the lux/lumens to default, and use distance to force the readout to match the known value. You can replace the ring stand with a mic stand and light clamp. Let me know if you have any questions!
**You might also be able to use a pinhole/diffuser, as the pinhole would be a “slice” of the image of the diffuser, which would hypothetically distribute the beam pretty evenly.
Also, a compound diffuser works better because of double diffusion for more even scattering.