This weekend I bought the really really small pentax infrared remote.
I found out the camera would not focus with the remote.
After searching my menu's and the net I found out I needed to enable AF with Remote option in the custom setting menu, I did just that but still the camera refused to focus!
So reverted back to the manual but at page 81 (in dutch there is only the mention of enable AF with Remote option) So after spending an hour I could still not focus with the remote. Then I saw that my lens was set in AF-C (continue drive mode) I had shot some kite surfers in the march storm in Holland) I switched to AF-S (Single Drive mode) and the camera did auto focus when using the remote.
To sum up there are 2 things you must do to enable auto focus with the remote.
- Enable AF with Remote in custom menu
- Set lens to AF-S (Single drive mode)
Hope this helps you