Lab: More or less good cheap lux meter

Vitaliy_Kiselev

It is not so simple as it can look, as you need sensor with proper spectral response as well as proper integration hemisphere.

Proper human sensitivity match (aka v-lambda curve) is a must. Most else you can compensate.

Good cheap lux meter that is more or less accurate (it is considered around +-10%) is, strangely, not so easy to get.

From really cheap ones, I suggest to get this one - https://www.aliexpress.com/af/lux-meter-lx1010b.html (with large white integration cover).

It is far from perfect, but not very bad for many lights.

Vitaliy_Kiselev

Not so cheap one

Vitaliy_Kiselev

Here is CIE defined V-lambda curve

Vitaliy_Kiselev

Even this function can have versions (newer one are more precise)