Overexposure Indication


FRV is not indicating all OE areas of images.  For example,  comparing the two lowest exposures of a three image bracket (EC = -2/3 and 1 1/3) the higher EC image shows a small area of OE but comparing the images with the exposure of the 1 1/3 image reduced by 2 to match the lower EC image there is clearly much more OE area.  I adjusted the exposure of the higher EC image to -5, OE areas not shown by FRV are even more evident. See attached screen capture from FRV.  How can I get FRV to correctly show the OE areas?  

It is hard to discuss without having files.

In general:

1) Shutters are not absolutely precise, so exposure difference in 2 stops then correcting to 2 stops will not result into absolutely same image (same pixel values)

2) There are slight light variations esp. in natural conditions (compared to halogen lamp powered by stabilized voltage)

3) There are light variations due to nature of light (photon noise)

4) FRV histogram/overexposure area calculations are not precise, but approximated to ~1/10EV

So don't expect that bracketed than exposure corrected shots will display absolutely the same overexposure area.

If you need precise (single value precision) overexposure calculation it is better to use RawDigger for that.


Alex Tutubalin/FastRawViewer team

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