Sigma 50-500mm F4-6.3 APO DG
I managed to purchase a second hand Sigma 50-500mm F4-6.3 APO DG lens that fits onto my Olympus E620 digital camera, with the aim of using it for wildlife photography. Although the weather has not been great, dull and grey, I did manage to try it out at a couple of locations recently, Fleet Pond and Haven Boatyard Lymington, and here are a selection of the images taken.
Great Crested Grebe (Podiceps cristatus) at Fleet Pond.

Sigma 50-500mm F4-6.3 APO DG on Olympus E620 at F8
Mallard (Anas platyrhynchos) at Fleet Pond.
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Sigma 50-500mm F4-6.3 APO DG on Olympus E620 at F8
Greenshank (Tringa nebularia) at Haven Boatyard Lymington.

Sigma 50-500mm F4-6.3 APO DG on Olympus E620 at F8 (image cropped)
Redshank (Tringa totanus) at Haven Boatyard Lymington.
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Sigma 50-500mm F4-6.3 APO DG on Olympus E620 at F8
and a Curlew (Numenius arquata) at Haven Boatyard Lymington.

Sigma 50-500mm F4-6.3 APO DG on Olympus E620 at F8 (image cropped)