Honestly, I'm just starting out with wildlife and I've been super cautious about spending $2000 all at once, you know? I've been looking at some of the market alternatives because the native Sony glass is just so pricey for a beginner like me. Tbh, checking out third-party brands might save you a ton of money without losing too much quality. * Sigma 150-600mm f/5-6.3 DG DN OS Sports - This one is usually way cheaper than the Sony G and the build quality seems really solid for those damp conditions you mentioned.
* Tamron 150-500mm f/5-6.7 Di III VC VXD - It's a bit shorter on the reach, but it's much more compact and easier on the wallet if you find a good deal. I'm still a little worried if the autofocus on these brands can actually keep up with birds compared to a real Sony lens tho. Like, is the savings worth the risk of missing a shot? I'm basically just trying to figure out which brand gives the most bang for the buck right now.

I've spent a lot of time out in the field with these and honestly, you might want to consider the long-term ergonomics before pulling the trigger. The Sony FE 200-600mm f/5.6-6.3 G OSS is a total powerhouse for the price, especially with that internal zoom. It keeps the balance steady on a gimbal and you dont have to worry about it sucking in dust or moisture in those damp conditions you mentioned. But be careful, it is definitely heavy for a full day of hiking. If you look at something like the Sigma 150-600mm f/5-6.3 DG DN OS Sports, its a solid build, but make sure to remember that Sony limits the burst rate on third-party glass. For birds, that frame rate cap on the A7IV could be a real dealbreaker if you are trying to catch action. I would suggest the Sony FE 100-400mm f/4.5-5.6 GM OSS only if you absolutely need to save weight. Its super sharp, but youll lose a bit of light and AF speed if you throw a teleconverter on it to get that extra reach. Just keep an eye on your shutter speeds if the light starts dropping under the tree canopy in those parks... let me know if you need more info on the weather sealing stuff specifically!

For wildlife photography with your Sony A7IV, the Sony FE 200-600mm f/5.6-6.3 G OSS offers excellent reach, sharpness, and weather sealing within your budget. While heavier than the 100-400mm GM, it provides superior focal length without needing a teleconverter.

I love my new SEL400800G. https://www.bhphotovideo.com/c/search?Ntt=sony+400-800mm+f%2F6.3-8+g+oss&BI=8941&KBID=10361&SID=12345&DFF=d50