I just got this Olympus OM-D E-M10 mark IV for my birthday and I really want to take pictures of the birds in my backyard but everything looks so tiny right now. I tried zooming in with the lens it came with but it barely does anything lol. I think I need a telephoto lens but when I look online there are so many numbers like 40-150mm or 75-300mm and I have no clue what that actually means for how close I can get to a squirrel or a bird.

So I was thinking maybe the 75-300 one because the number is bigger? That makes sense in my head at least. But then I saw people talking about pro lenses that cost like two thousand dollars which is way out of my budget since I only have about 500 or 600 bucks to spend. My logic was that a bigger number is better for distance but then I read something about light and f-stops and now my brain is just mush honestly. I'm going on a trip to some wetlands in Florida next month and I really want to get some good shots of the herons and stuff without them flying away because I'm too close.

• Is the 75-300mm lens actually okay for a beginner?
• Does it matter if the lens is a different brand like Panasonic?
• Will it be too heavy to carry around all day?

I'm sorry if this is a dumb question I just dont want to buy the wrong thing and be stuck with something I cant use...