Have you considered an all-around lens ? The DA18-250mm and DA18-135mm are in that category although the former (DA18-250mm) has a longer reach.
I travel often overseas (Asia, Europe, North-America, Australasia) and I want to travel light. I also want to avoid lens swapping. I have two preferred combo to travel light (cabin luggage only):
- K-7 + DA18-250mm, or
- K-7 + FA31mm
The first combo is my favourite and covers nearly all my needs. However, there some instances when I want image quality and the second combo (FA31mm) is my preferred choice.
When I travel with more than a cabin luggage, I would also consider the combo:
- K-7 + DA18-250mm + Voigtlander Nokton 58mm f1.4
The DA18-250mm being the lens mounted on the K-7, while the Nokton 58mm f1.4 (a fast prime) covers the low-light situations.
Food for thoughts and Hope that the comments will assist...