Hi guys I currently have a6500 with 18-105mm f4 which is a good all purpose zoom but generally quite big. I am looking for a very portable lens, ideally suitable for low light for travelling. I do not mind if it is a prime, but I am looking for the best compromise quality/weight and size with preference towards lower weight and size. I am thinking if the pancake 20mm 2.8 is the best option? As a nice to have would be weather sealing (wouldn't mind paying extra for this feature).