Lens Choices for Spotting at Denver (DEN) - Any Recommendations?

Hey folks, looking for some advice on lenses for plane spotting at Denver International (DEN). I've been using my trusty 70-200mm for a while now, but I'm thinking it's time for an upgrade.

The airport is huge, and I find myself wanting a bit more reach, especially when shooting from the parking lots or along the perimeter fence. I've been eyeing the Canon 100-400mm and the Sigma 150-600mm. Has anyone used these at DEN? I'm curious how they handle in terms of sharpness and focus speed, especially for takeoffs and landings.

Also, any tips on where to position myself to get the best shots would be awesome. I've heard the south side can be good, but not sure if that's still the case. Appreciate any input from those who've spent time spotting there!

I've used the Canon 100-400mm at DEN and it's pretty solid for the distance you need there. Sharpness is good, and it handles focus speed well enough for takeoffs and landings. I haven't tried the Sigma 150-600mm, but I've heard it's decent too, especially if you need that extra reach. As for positioning, the south side is still a favorite for many spotters. Just be ready to move around a bit depending on the wind direction and runway usage.

I've tried both lenses at DEN. The Canon 100-400mm is great for versatility, but if you want serious reach, the Sigma 150-600mm is hard to beat. It's a bit heavier, though, so be ready for some arm workouts. The focus can be a tad slower on the Sigma, but it still does a decent job tracking takeoffs. As for spots, the south side's still decent, but I usually head to the west side near Pea Blvd. You get some cool angles there. Have you considered a monopod to help with the weight?

I've used the Sigma 150-600mm at DEN, and it's a beast for getting those distant shots. It is heavier, so maybe think about a monopod if you're out there for a while. It's super sharp, especially in good light, and the autofocus is snappy enough for takeoffs. As for spots, the south side's still decent, but check out the new tower area if you can. It's not always open, but when it is, the views are killer! Have you considered a teleconverter for your 70-200mm as a budget-friendly option?

I've got the Sigma 150-600mm, and it's been great at DEN, especially for those far shots. The weight can be a pain, though, so a monopod is a lifesaver. The focus speed is decent, but if you're after fast-moving stuff, it might take a bit to lock on. I've had good luck on the south side, but honestly, it depends on the time of day and traffic. Have you thought about renting one to test out before buying?

I'd go with the Sigma 150-600mm if you're after reach. The extra distance is a game changer at DEN, especially when you're shooting from the perimeter. Just watch out for the weight; a monopod is a good idea. As for spots, the south side is still solid, but I've also had luck near the Westin hotel for some different angles. The Canon 100-400mm is nice for flexibility, but if you're focusing on reach, the Sigma is worth it.