Originally posted by GaryML This feature already exists. You can use a Pentax hot shoe flash (such as the AF-360FGZ) and set it to focus assist "spot beam" only (set Mode to "SB"). Then the flash will project a red pattern for AF assist when needed, but the flash will not fire when the shutter is released.
Yes, you can do this... but who wants to put on a flash of that size that has at best a 2 meter (6 feet) range of assist with the dim red led output. The Sony holographic assist was the best around, and Pentax needs to do something other than blinding the subject with a buzz flash assist which really does not work well, or like others a pencil beam that blinds... it is a tough call, but there are options.
A small push button LED pencil flashlight or torch works in some cases to get focus lock, and on one shot I wanted of 4 birds in a tree at night huddled together I used a high end bicycle light to get the focus, then the AF540 fired for a perfect shot. The birds were 10 meters (34') up in the tree.
I am also experimenting with a small patterned laser assist pen light, based on the Sony laser diode, this may be the answer for me when I get it finished.
Phil