One of my brother's took his son and daughter in law on a photo safari to Africa for three weeks. His son rented a long lens as he really didn't want to spend what the one he was looking at cost. Three weeks and not counting air fare to Africa the cost was $64,000! Spend the money if you think you'll have use for it later on. Compared to the trip cost, it's pennies! I have a few of the photo's the nephew took over there with the long lens and they are really special! if you can't at least afford to rent the lens you want, you can't afford the trip in the first place!