Finally pulling the trigger on a wide lens for my R5 but I'm totally stuck between the RF 14-35mm f4 and the 15-35mm f2.8. I'm heading to Iceland in like two weeks so I need to decide fast. The f2.8 is tempting for potential northern lights shots but it's so much heavier and way more expensive. Since I mainly do landscape I'm usually stopped down anyway. Is that extra millimeter on the 14-35 really noticeable?

My constraints:

• Budget is strictly under $2300
• Need something that wont break my back on 10 mile hikes
• Weather sealing is a must because of the rain

Should I just go for the f4 or is the f2.8 worth the extra weight?