Compact/bridge cameras etc - Flash +/- compensation

[panblue]

-2 0 +2 flash compensation ..is '+1' four times the power of '0'; '-1' a quarter of the power of '0' ? and so on.

And while I'm asking .. is f2.8 four times the light of f3.5 (twice the aperture, four times the light? ..or only twice the aperture, twice the light). Never made much difference to me, but curious )

 

[Big Mike]

I'm not entirely sure how P&S cameras do it...but if they follow what 'real' cameras do, then every 'Stop' (or EV) is twice as much. So +1 is twice as much as zero....+2 is twice as much as +1 (four times as much as zero).

As for apertures...again, every 'stop' is twice as much (of half as much) light. But it's not a straight numerical scale. The scale works on a factor of 1.4 (square root of two). So if we start at F2.0, F2.8 is half as much light as F2.0....F4 is half as much as F2.8....F5.6 is half as much as F4....F8 is half as much as F5.6....and so on.

 

[panblue]

Thanks man!

 

[MLeeK]

I think you are getting confused with the increments which are usually 1/2 or 1/3 stops. It sounds like half stops is what the camera is reading.
FULL Stops are .7, 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32
The numbers in between there are either 1/2 or 1/3 stops depending on what the camera is set for. Most cameras you can choose if it is 1/2 or 1/3 stops.

 

[panblue]

I think you are getting confused with the increments which are usually 1/2 or 1/3 stops. It sounds like half stops is what the camera is reading.
FULL Stops are .7, 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32
The numbers in between there are either 1/2 or 1/3 stops depending on what the camera is set for. Most cameras you can choose if it is 1/2 or 1/3 stops.

Thanks..yea I know my full-stops .. I thought it may be one of those power law situations going-on with the magnitudes. But it's straight doubling/halving. Thankyou!

Edit: it is.

 

[2WheelPhoto]

Camera Exposure: Aperture, ISO & Shutter Speed

 

[panblue]

Camera Exposure: Aperture, ISO & Shutter Speed

Thanks for the link. I'm familiar with CinC website and general theory..sometimes I forget myself.

To quote that page ..Every time the f-stop value halves, the light-collecting area quadruples.

See .."quadruples" not doubles. This is the point i wished to clarify.

I thought I read something the other day, here which made me question this was posted as advice.