Stretching

We went to the WWT at Arundel today for a short wander. I was trying a different lens as my Sigma 50-500 has now died (the auto focus doesn't). This lens was lent to me by a colleague at work but what I would actually be looking at is the Sigma 150-600 (not the 150-500 that I was lent) which Sigma would let me have at a discount as they can't repair my lens. I still need to be able to justify the outlay though. :-(