If I were you, I'd stay away from that deal/lens. It would be a total waste of money. Something very important is missing from the specs, the the aperture! The complete page talks about many things but the specs in detail. The most powerful telephoto lens cannot be at that price
I assume you are looking for a telephoto? I would stick to the accessory lens if supplied by Sony for the F828, that should be your best bet. Since F828 is not an SLR the choice would be rather limited. Is the built in lens not sufficient for your needs?
You seem to be trying to do things with the Sony which would be much easier if you had an SLR I guess you should start to think about upgrading to one if you need the flexibility. I know it is not a small expense upgrading but the truth is you seem to be having the skills and the interest to explore but the Sony is prooving to be a bottleneck.
I would but im not really into it that much to go spending an extra 400 - 500 pounds on something I dont use everyday.
I wouldnt get that much for the camera now maybe 300 - 400 if im lucky which is pretty much nearly half price. Not worth it imo
I think i'll just make do for another couple of years, after all it is a damn good camera for what I need to do from a amatuar perspective if you know what I mean ?