Does Metering System works with Flash ?

[aroy]

I have found that Matrix metering works best with flash. The CW or Spot is not consistent. Professionals use specialised flash meters to calculate the reflective light and then set their exposure accordingly.

For indirect flash, you have to find out how much compensation is needed. It cannot be fixed, as each room has different reflectivity. The contribution of fill flash will be less for a bright ambient and increase as the ambient light decreases.

 

[WayneF]

There is more to it. Matrix, Center Weighted, or Spot metering modes are only about ambient light. The flash system instead has and uses its own central metering system. So the flash system does NOT do spot metering, but since spot metering is NOT a balanced situation, then Spot does switch flash metering from TTL BL (affected by balancing with ambient), to be TTL (unaffected by presence of ambient).

Nikon is a TTL BL system, and the default mode for flash is TTL BL.

For fill flash outdoors in sun, TTL BL is very handy, doing automatic flash compensation (flash reduction, i.e., balanced flash).

For flash indoors, TTL BL can tend to underexpose, and TTL mode becomes a favorite. TTL comes ahead on as metered, regardless of any ambient.

A few flashes have a TTL vs TTL BL menu to select flash metering mode. Frankly, this does help understanding and use. Those that don't have the menu default to TTL BL, but we can specify Spot metering or FV Lock to make sure the TTL flash has full capability indoors (the flash never does Spot metering). In that way, Spot metering commonly helps flash indoors, but the thing about Spot though, if you don't reset it Off when you go back outdoors, expect some bizarre results then when you have ambient.