I wish I'd known about that lens when I decided to get my first telephoto lens in 1986. I bought a Vivitar 70-200mm f/4.5-5.6, definitely not one of the well-regarded Series 1 versions but a later and inferior model. It had mediocre performance with very low contrast at longer focal lengths. I lugged that thing all over the mountains on hiking and backpacking trips, when I would have been better off with a used Series E 100mm offering much better optical performance, better low-light performance for my ASA 64 Kodachrome, and much less weight.