The difference between fact and personal opinion, feeling or judgment based on them is objective proof.
Light meters, being devices, do not have opinion or feeling. It can be demonstrated that most material existing things are sources of ‘light’ quanta, stimuli, either being emitters such as light bulbs or reflectors. The exception being objects coated in highly absorbent paint.
Human-kind knows how eyes and camera like devices function, being receivers of ‘light’ quanta, stimuli input.
To be sources of stimuli the objects must exist. They can not themselves be products of observation.
If objects are existing, not as observation products, but material things the particles from which they are composed and particles they emit or reflect must also be existing.
Not being relative observation products, they can not be occupying the same sensory or device generated space as them.
When testing a particle, the existing particle, the apparatus and experimenter (bodily) are not relative to ‘this way of testing’. They exist independently of the test. unlike the relative measurement product.