I would like to know how you are reading the meter's information in the camera's VF. Of course, the meter is not always right, and you have to know when that will occur and then use the Manual mode to take meter readings on a certain part of the scene, but for a scene of this sort with a good balance of lighter and darker areas, the meter indication should be fine. Your first two have good exposure settings and were shot in Manual mode, while the last two are under exposed, and were shot in the Landscape mode- one of the automated "Scene" modes. This mode will assume the desire to be maximum DOF, and will therefore automatically set as small an aperture as possible with the degree of lighting and the ISO, in this case f/16. Metering for exposure will be automatic. Why the camera under exposed in this mode is mystery, as the K-x is known for tending towards over rather than under exposure. Could be the lens too, not being as accurate at smaller apertures. When you see this kind of thing happen in any of the automatic exposure modes, just employ your exposure compensation control.
It appears you might be using the standard multi-point AF setting, so the camera might be choosing the wrong point to focus on, which here might be the tree branches in the foreground to the left, since they are closest to the camera. If you use spot AF instead, you can train it where you decide, hold the focus, reposition the camera while holding focus, and then complete the shutter press. Doing that and getting the results you are looking for will take practice as to just where to train your focus, and what aperture is best to use.
You should not require a tripod for a scene in good lighting like this one, as it will not be difficult to get high enough shutter speed at whatever aperture you will need. But if you will be doing a telephoto shot and want better DOF, you will definitely need a smallish aperture, and a higher shutter speed than you would with a normal or a wide angle shot.
Last edited by mikesbike; 06-29-2019 at 01:58 PM.