Whats the best budget-friendly zoom lens for a Canon R10 if Im mainly doing outdoor stuff? Ive been diving into some reviews and I keep seeing the RF-S 55-210mm mentioned as the go-to cheap option because its small but then everyone on YouTube says the RF 100-400mm f5.6-8 is the hidden gem of the whole RF lineup.

I'm taking a trip to the San Diego zoo next month and then there's a local airshow in July so I really need some actual reach that my 18-45mm kit lens just cant do. My budget is pretty tight around $500 maybe $600 if I really stretch it or find a good used deal.

Im torn because the 100-400 looks amazing for the distance but I'm worried it might be too heavy or unbalanced on the tiny R10 body plus that f/8 aperture at the long end seems really dark? Then again the 55-210 feels like it might be too short for planes or animals far away. Some people say just get an adapter and buy an old EF lens but that sounds bulky and I dont really want to carry a giant setup around all day. Is the 100-400 worth the extra cash for a casual hobbyist or am I overthinking the aperture thing...