> Which lens offers the best 'bang for your buck' for a beginner? Honestly, grab a used Tamron SP 150-600mm f/5-6.3 Di VC USD!! Its like sooo much reach for the money and actually fits that $600 budget perfectly, right?

Quick question - what camera body are you actually shooting on? Before I give advice, knowing if youre on a crop or full frame is huge for AF reliability and reach. I'm kinda obsessed with the technical safety and long-term durability of gear, so its worth thinking about. Heres a quick comparison of the safest bets in your budget: 1. Canon EF 100-400mm f/4.5-5.6L IS USM
- Pros: Highkey reliable AF speed since its native glass. Built like a literal tank.
- Cons: The push-pull design is basically a dust vacuum, which can be a maintenance nightmare if the seals are old... it might even damage your sensor if its really dirty. 2. Sigma 150-600mm f/5-6.3 DG OS HSM Contemporary
- Pros: That 600mm reach is unbeatable for birding. Modern optics are actually decent for the price.
- Cons: Third-party AF can be hit-or-miss on older EF mounts, and you might need to buy the calibration dock for firmware updates to keep it stable, right?? Both are solid, but let me know your camera model so I can check compatibility specs for you! gl!

> Which lens offers the best 'bang for your buck' for a beginner? Sooo, I've been shooting wildlife for over 15 years now, and honestly, you can find some amazing deals if you're okay with older gear. For your situation, I'd suggest comparing these three options: 1. Canon EF 100-400mm f/4.5-5.6L IS USM (Mark I): Pro is the L-series optics and stabilization. Con is the weird "push-pull" zoom mechanism which takes time to get used to.
2. Canon EF 400mm f/5.6L USM: Pro is the insane sharpness and lightning-fast AF for birds. Con is no stabilization, so you gotta keep shutter speeds high.
3. Tamron SP 150-600mm f/5-6.3 Di VC USD: Pro is that massive 600mm reach. Con is it's realy heavy to carry all day. In my experience, the 100-400mm is the best all-rounder. I've used it for a decade and it never let me down. That L glass is just built different than the 70-300mm!! Good luck.

yo, i feel u. wildlife glass is highkey expensive, but there are definitely some gems if you look at the used market. honestly, for your $600 budget, you really gotta look at the Sigma 150-600mm f/5-6.3 DG OS HSM Contemporary. it's basically the gold standard for budget wildlife. i've used it for years and having 600mm reach is a total game changer for birding compared to a 300mm lens. basically, at 300mm, you'll still be cropping too much for small birds. the AF speed on the sigma is surprisingly snappy, especially on a mid-range dslr. but if you want the absolute fastest autofocus possible and dont mind a prime, try to hunt down a used Canon EF 400mm f/5.6L USM. it's an older L lens without image stabilization (IS), which is kinda a trade-off, but the optics are literal perfection and the AF is basically instant. it's super light too, which is great for trekking through the woods. the Canon EF 70-300mm f/4-5.6 IS II USM you mentioned is a solid lens, but i'll be real... 300mm is just too short for birding. youll end up losing all your resolution cropping in. idk if you've checked out the Tamron SP 150-600mm f/5-6.3 Di VC USD G2 yet, but if you find a used one for $600, thats another killer option with better weather sealing. but for pure bang-for-your-buck, the sigma is the winner. gl with the deer!! peace

Facts.

Been using this for years, no complaints