The latest version of this lens is the 50-500mm F4.5-6.3 APO DG OS HSM. Breaking that down: it is a long telephoto zoom obviously, of APO design to reduce CA, DG is a digital coating to reduce reflections from the digital sensor, OS is optical stabilization and finally HSM is a ring-type focusing motor.
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| SIGMA 50 500MM 4 63 APO EX HSM LENS F EOS | |
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$540.00 Time Remaining: 22d 49m Buy It Now for only: $540.00 Buy It Now | Add to watch list |
| Sigma 50 500mm f 45 63 APO DG OS HSM SLD Canon 50 500 | |
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$1,599.00 Time Remaining: 3d 5h 13m |
| Sigma 50 500mm f 45 63 APO DG OS HSM for Nikon 50 500 | |
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$1,559.00 Time Remaining: 3d 5h 19m |
| Canon Sigma 50 500mm OS f 45 63 DG HSM APO Lens | |
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$1,325.00 Time Remaining: 11d 16h 27m Buy It Now for only: $1,325.00 Buy It Now | Add to watch list |
| Sigma EX APO HSM 50 500mm F4 63 AF D Lens For Nikon w Cap Case Box | |
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$495.00 Time Remaining: 4d 10h |
All around this is a well known and loved lenses. In some circles it is also known as the "Bigma" due to its size.