[infosyn]

Just thought you folks might want to read a review of Sigma's new 50-500 mm f/4.5-6.3 APO DG OS HSM, affectionately known as Bigma. They review it on a Canon EOS 50D, so the results should be fairly relevant to Pentax users. They compare the Sigma with a Sigma 150-500 (somewhat cheaper) and Canon 100-400L (about the same price) lenses.

Sigma 50-500 mm f/4.5-6.3 APO DG OS HSM review - Introduction - Lenstip.com

Some of their interesting observations:

- The new model is not optically identical to the classic Bigma, having a couple new elements and somewhat different optical parameters, including higher f4.5 at 50mm and a closer focus distance. Weight is still high enough to overwhelm a tripod: 1.97kg.

- The minimum focus distance is much better than the old version; at 50mm it's 0.5m and at 500mm it's 1.8m. Still nowhere near true "macro" capability, though, since the maximum magnification claimed (at 200mm) is 3.1:1.

- In-lens OS is good, about 2.7EV, but as usual with lenses, nowhere near the claimed 4EV.

- Resolution at frame center is slightly better than the old Bigma, but nothing to write home about. Sweet spot looks to be at f11, which is what I found for the old Bigma, too. Edges are bad above 300mm, as you might expect.

- Chromatic aberration is slightly worse than the Sigma 150-500, not nearly as low as with the Canon 100-400L lens, but not a serious problem.

- "Silent and efficient" auto-focus, no front or back focus. This sounds like a vast improvement over the old Bigma.

- Non-rotating filter mount is 95mm. Comes with a filter adapter that lets you mount an 86mm filter when used with an APS-C sensor.

LensTip.com concludes that Canon users are better to stick with the Canon 100-400L, but of course that option is not available to Pentax users. List price is $2400. B&H and Amazon have Nikon or Canon mount at $1600, a 50% bump from the old non-OS version. Amazon lists the Pentax mount as "Not yet released.": http://www.amazon.com/Sigma-50-500mm-4-5-6-3-Telephoto-Pentax/dp/B003A6H2JS/...4123414&sr=1-4

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Last edited by infosyn; 05-17-2010 at 12:13 PM.

[Adam]

Has someone with knowledge on the matter added the new version to the 3rd party lens database yet? PentaxForums.com Third-Party Lens Review Database - Lens Listings

[yeatzee]

- The minimum focus distance is much better than the old version; at 50mm it's 0.5m and at 500mm it's 1.8m. Still nowhere near true "macro" capability, though, since the maximum magnification claimed (at 200mm) is 3.1:1.

WOW! Only the canon MPE-65 can get closer w/out anything added! Puts my macro lens and reversing lenses to shame :ugh: