
*** Build Information ***
CHDK for a420 fw:100b PID:12559
build:1.7.0-6343 date:Sun, 21 Sep 2025 04:47:18 +0200

*** Camera specific notes ***
****************************************

Camera depending notes: 

- A420 uses Propset 1 of Properties (see http://tinyurl.com/6zbv9b)
- The A420 does not have an iris diaphragm, it has a smaller snap-in aperture (not an ND filter)
  Seen this in a dismantled A430 optics, suspect the same in at least the A410 - A430 models.
  The CHDK controls this the same as an ND-filter.


Changelog

Beta 2, 2011-08-22
- modemap is now correct
- movie mode is now supported (quality override, zoom, af-scan, exposure override works, filesize can grow over 1GB)
  crashes, when af-scan is attempted during 640x480 movie recording (no such problem in 320x240, 160x120 mode)
  A430 also exhibits this problem
- aperture table corrected
- movie time limit lifted to 1 hour / recording in 320x240 and 640x480 modes
- USB remote should work

Beta 1, 2011-06-25

- based on A430, thanks to the authors of that port
- the loader part almost identical (changed one led address in an inactive function)
- USB completely untested, don't know if it works or not, A430 stuff without change

- sensor data the same as in A430 (probably the same sensor in the two models)
- RAW/DNG works, RAW is only recognized by DNG4PS2
- RAW/DNG file numbers work as expected (using hack from A530)
- extra long exposures work (tested with 80sec), shutter speed override works
- flash adjustment seems to work
- zebra works
- grids work
- histogram works
- manual focusing works, but barely usable (small display resolution)

As the mechanical shutter and the "ND-filter" (see above) is broken in my camera, can't test their functionality.

Bugs
- AF-scan causes crash during 640x480 movie recording, works fine otherwise


Camera specific CHDK behaviour:

- enabling both "video quality control" and "enable optical zoom" in the "video parameters" submenu is not recommended
  pressing the up/down buttons would zoom AND change compression quality at the same time


LED ADDRESSES

AF_LED		0xC0220080
BLUE_LED	0xC0220084
RED_LED		0xC0220088
GREEN_LED	0xC022008C
ORANGE_LED	0xC0220090

