I figured I'd put together my own thoughts on the DB Aperture menu since so many people are having trouble using it or keeping settings. Hopefully this explains things a bit and helps someone.
DB Aperture menu - This is found in the Service menu, do so at your own risk -- Menu, Information tab, Up, Down, Up, Down
DB Aperture Position - This displays the current position (this value does not update in real time, you must exit the DB Aperture menu and re-enter it to see the updated current position)
DB Aperture Max. - This sets the maximum (closed) position Dynamic Black (iris) will use
DB Aperture Min. - This sets the minimum (wide open) position Dynamic Black (iris) will use (This is the position the aperture is moved to on power up when Dynamic Black is disabled.
DB Reset - This resets the aperture to 0, then to the aperture min position. This is useful after a sudden power loss, or if the aperture position appears to be 'drunk' (too open or too closed at all times -- screen super dim from a power on) For some reason, you can run this 3 times, and each time it ends up at a different 'home' position, one of them being correct.
DB Enable - Turns Dynamic Black on or off without leaving the menu
Reset DB Max/Min Aperture - Clears all DB Aperture values back to default for your firmware (after you select this, exiting the DB aperture menu and them re-selecting it will show all default values)
DB Aperture Position Calibration - This will attempt to calibrate the position of the aperture (metal disc in light path with a slot that widens the light path as it's rotated). Be warned that this will exit the service menu after running, and there's a chance you'll end up with the aperture disc completely blocking the light path. You can sometimes power up and down (removing plug after full power down) to get the aperture to rotate to the 'home' or 0 position.
- Aperture Min and Max will have no realtime affect if DB Enable is Off
- Aperture Position manually moves the aperture, but will only work if DB Enable is Off, otherwise DB holds the aperture where it desires
Quick steps to tweak this area as a starting point:
- Set DB Enable to Off
- Adjust the aperture position up and down to see how the values affect the picture in realtime.
* Note * the 'Aperture position' value listed does not update as the aperture position changes, if you hit exit then re-enter the DB Aperture menu, that value gets updated, it is for informational purposes only.
- You should notice the image is brightest around 13, if this isn't the case, the aperture disc is likely out of position, and you may benefit from selecting DB Reset until it is bright when positioned at 13.
- You should also notice the image is it's darkest around 55-60.
- Take note of what point you want as your brightest and power on point, set your DB Min to this, typically 13.
- Take note of what point you want as your lower light output, set this as your DB Max, typically around 54.
- You can now set DB Enable On and it will auto adjust the aperture position
- If you didn't achieve your desired effect, try Reset DB Min/Max Aperature to set settings back to defaults, or the other settings mentioned in this thread.
It would be a good idea to carefully note the key presses to enter the Service menu and enter the DB Aperature menu, then select the DB Reset option. If you run in a scenario where the aperture disc is blocking the light path from power on, you can press that key sequence to regain enough light to use the on-screen menu again and recover.