[deepbluish]

Has anyone else updated their firmware for this flash?

I've just bought one and tried it on my K-5 prior to updating the flash to the latest firmware. The latest firmware allows the flash to work on the K-1.

I've checked all the flash's function on the K-5 and I know that the AF assist beam light was working. After having updated the firmware, the beam does not engage even in a completely dark room.

Does anyone have a clue what could have happened?

[Class A]

Does anyone have a clue what could have happened?

Make sure that you are able to provoke the camera's AF-assist light. For instance, the K-5's focus mode should be set to AF-S.

If you can make the camera use its AF-assist light then adding the flash (potentially using the right flash mode) should make the flash's AF-assist light come on.

I have noticed that Metz have removed some functionality in some of their latest firmware updates (support for analog TTL) for some models, and the K-1 cannot use the AF-assist light of the classic FGZ models, but I have never heard of a K-5 AF-assist light issue before (which does not mean that it doesn't exist).

[Class A]

FWIW, I just tried my Metz 58 AF-2 (latest firmware version V5.0) with my K-5 II and the AF-assist light of the Metz is working with that combination. However, I had to make sure the flash was in "P-TTL" or "P-TTL HSS" mode.

[deepbluish]

I should have done a better search on the forum before posting the question, but in the end it might be easier for someone else to find an answer this way.

There's this thread in the Pentax K-1 section https://www.pentaxforums.com/forums/190-pentax-k-1/325879-k-1-metz-flashes-good-news.html

It appears that this problem is K-1 specific only. It appears that the K-1 cannot trigger the assist beam on older flashes (Pentax native included). It only triggers the beam on mark II versions of 360 and 540.

I tried my Metz 44 again on my K-5 with the option of the camera's own assist light turned off and the beam on the flash is triggered by the camera without any problems.