First, when I tried to use set_shot_meter(1,2,2,98,98) it returned an error (nil value). The other enhanced histo calls are working. Have I got the call right?
Oops! The actual call is:
shot_meter_enable(1,2,2,98,98)
I feel like an idiot, so that should fix the problem.
• In RawDigger I see three lines lines on the image, on the left, right and bottom edges, ie a ‘few’ pixels in from the edge. I assume these are the ‘dead’ areas that any RAW processing ignores?
Sorry, that's something my program did for debugging. I write the metering areas into the raw file on the first shot, which show up as blown pixels in the first histogram. The work-around is to throw away one shot:
shot_histo_enable(1)
shoot() -- throw away shot with meter boundary lines
This post explains the metering boundary thing a little better:
http://chdk.setepontos.com/index.php?topic=8997.msg94890#msg94890• According to the WB setting (I took images of a neutral wall) there is a spike of about 2000 in RawDigger at 127 or 128, it varies according to WB. This data seems to be there all the time.
• Both the S95 and the G11 have these spikes around 127 and 128, even when I over expose the image, ie histogram way to the right.
I think those could be the debug metering lines showing up too. I write 2 black level lines next to a white level line. If throwing away the first shot doesn't help, it may be the active area is too large.
I'm using the entire "active area" of the camera, as set in the camera specific data when the camera port is done.
All around the active area is a masked area that never gets any light. I suspect that the active area values may extend into the masked area a little, which would produce constant black level pixel counts in the histogram. See if shot_meter_enable(1,1,1,99,99) or shot_meter_enable(1,2,2,98,98) changes anything. I may need to shrink the default full histogram area a little smaller than the active sensor area.
• There appears to 'always' be a spike at 4095, also about 2000 count in RawDigger, even when I underexpose and skew the histrogram way to the left.
And my work around is?
This should only happen on the first shot after shot_histo_enable(1) if it's my program writing the meter areas in the raw file. I'll take this out, or make it an option, when I'm finished debugging the meters. In the meantime, throw away the first shot as described above.
BTW I have noticed that the G11 is much slower at running my script than the S95. Just an observation.
My G1X has the DIGIC 4, and is a little slower than the SX260 with the DIGIC 5 in my timing test. Sounds like the G11 must have the DIGIC -1 or something.
