JD750 Loc: SoCal

Yep that requires a lot of exposure range.

FY - I love backlighting!

Grahame Loc: Fiji

For info I undertook a controlled test to compare the two 'blinkie' profiles I made, the one using Flat and the other using Standard.

Set my monitor to white, camera in Aperture priority EC +2 and adjusted the camera using each profile to the point where the blinkies stopped. I estimate 1/2 of a 1/3 of a stop difference, negligible and may be caused by difference in my curve adjustments.

I also undertook a test using the monitor to confirm the strange inaccuracy of the 'highlight' metering due to ratio of light to dark areas. The blinkie method should be far more reliable when addressing a scene with a small bright area, e.g. just prior to sunrise.

selmslie Loc: Fernandina Beach, FL, USA

The blinkies are a reliable indication of where the raw values are in relation to the raw limit so long as you stick to one white balance in the camera.

It's different for each manufacturer but it may be consistent for Nikon models where they can start at about 2/3 stop before the green channel blows out for Daylight WB. The trigger can be different for other WB settings and they may show up too late with UniWB.

For my Fuji they start just as the green channel reaches the limit and starts to blow. For my Sony they start about a full stop before the raw limit and I can make them happen sooner. With newer Sony models this can be moved closer to the limit.

To figure all of this out requires careful study with a standard target and looking at the results with RawDigger. To get a clear view of the right end of the histogram you should set the Y-Axis Range Scale to "Logarithm".

In the attached example you can see that there are 218 overexposed green pixels and the histogram shows about 500 pixels recorded at or above the the green raw limit.

In this shot the blinkies were just starting in the sky and only the green channel is reaching the limit.

(Download)