Telephoto for landscapes - 40-150mm f2.8 or something else?

I feel from personal experience in the field, all three are quality lenses. I think it comes down to the amount of light you have to work with. In good light, that is as long as you can keep the ISO the same for all of them, I'm finding the difference between the results is not worth debating, that even side by side they look similar, and not side my side I doubt if anybody could say which lens made the image.

For me it comes down to a matter of conditions. I would not take the 75-300 in the rain or the snow. The 14-150 won't make as good an image at ISO 800 as the 40-150 PRO will at ISO 200 - if you want the best chance of getting the shot under adverse conditions, you have to have the 40-150 PRO. That's why I own it.

In good light, and dry conditions, I'd rather carry the 14-150, crop a little if I have to and/or the 75-300. Both of them combined weigh less than the 40-150 PRO and the TC and cover a bigger range.

The original post discusses hiking and shows images of snow. That makes it a little problematic. On a long mountain hike, 5 miles or more I can feel another pound in the pack and held to my face. In snow, I'd have to be careful with the 75-300 but I prefer to travel light.

I'd carry the 14-150 and a bright prime, probably the 17 f/.28 because its fast enough, pancake, relatively inexpensive and weighs nothing or splurge on the 17 f/1.8.

I like carrying a fisheye. The Rokinon works well for me cropped to rectilinear, or de-fished.

Now that I'm putting more and more gear in the pack, I appreciate dropping one pound by leaving the 40-150 PRO an the TC home. I feel it in the pack.

I take the 40-150 PRO and TC only if I am pretty confidence I need it. The 14-150 is a lot slower but I can usually get a good photo with a slower shutter speed. There is also HDR if you can steady the camera.

For me its a decision between weight and the need for f/2.8 because optically, on an M43 camera all three lenses make good images. I think, the skill of the photographer and the time / location / composition are more important than the choice between these three lenses unless you are shooting in light and conditions that force the ISO up to 800 and more and you need all the detail you can get.