Light metering Question

[Rogier]

I just compared the readings from that meter with my Canon 5D.
It appears to me that there are often huge differences in the readings 😡

I made sure that the camera was not set on spot metering.

Can anyone tell me understand what might be going on?

 

[Sparrow]

Incident and spot meters are usually set to read at 18% grey (the perceptual mid grey for a human) so if you get a 18% grey card under the same light they will give the same reading

Unfortunately human skin is only 10-14% grey so when they make ttl or reflective metres for amateurs use and the man on the Clapham omnibus points one at his girlfriend if they use 18% as the centre-point you’re 2ish stops under-exposed, so they don’t they all set them off by a bit

 

[Sparrow]

The problem is they don’t seem to be able to decide what I bit is, there is a manufacturing tolerance to add in, and with TTL an allowance has to be made for the sky so they are weighted to the bottom of the frame.

All any meter can do is measure the light, sadly it can’t work out the exposure; and in making it easer for amateurs not to screw up they have made it very difficult for people like us, who think they know what they are doing

 

[Rogier]

I have tried incident and reflective (using the diffusor for the incident right?).

The 5D is set on center weighted and set on 40mm focal length.

Indeed while measuring off the grey wall in my office with reflective the reading was close. Same when I was doing the metering incident from the wall facing the camera.

But all other readings are often up to 3 stops of....