With the 500mm space littered with insanely expensive (read $10K to $15K) prime lenses I've entered the market with a value proposition lens. The Sigma 50-500 OS has an RRP of around $2000 here in Australia but generally sells from around $1500 on the street but I managed to get a pricematch here in Sydney at Georges to $1335 (incl 2 year Sigma Aust warranty) which I was quite happy with.
Probably the only other competitive options in this focal length at around this price range are the aging Nikon 80-400mm VR f/4.5-5.6D ED (which is 100mm shorter, has VR but is reputed to be slow to focus on all but high end bodies), the older 50-500 non OS and the slightly cheaper Sigma 150-500mm f/5-6.3 APO DG OS HSM (which is 100mm longer at the short end and is reputed to be not quite as sharp as the 50-500 bigger brother) and the Tamron SP AF200-500mm F/5-6.3 Di (which has no stabilisation and is apparently not very good). One other very viable option is the very good Nikon 300mm f/4 with the 1.7x teleconverter giving you a 500mm f/6.3 prime lens (Gerry shoots this exact combination and whilst it possibly is a sharper 500mm lens it isn't as convenient a range). To be fair Cameron tried to steer me towards the Nikon 80-400 VR and others have extolled their distrust of Sigma lenses (however I already have two - the 8-16mm and the 50mm f/1.4 (which I absolutely love and reckon it's probably my best lens and better than any Nikon lens I own)). I did try the Nikon 80-400 VR, the Sigma 150-500 OS and Sigma 50-500 non OS on my camera body but in the end decided to opt for the longer reach and convenience of the well regarded BigMOS.
Unlike true fast primes in this focal length arena these lenses (with stabilisation) are designed to be both hand held as well as shot on monopods and tripods. Whilst the new Sigma 50-500 OS is quite large and heavy at 2KG it pales in comparison to say the $11,000 4KG Nikon 500mm f/4 or the $12,000 4.6KG 400mm f/2.8G or the $14,000 5KG 600mm f/4.
You probably couldn't expect too much of a 10x zoom lens spanning focal lengths from 50mm to 500mm (75-750mm equivalent focal range on my crop sensor DX Nikon D7000 camera) but online reviews and reports seem to bely it's apparent compromises. Typical reviews online indicated the following general Pros and Cons of this lens:
The Pro's: very useful focal range, 500mm at a 'budget' price, optical stabilisation, hand holdable, quite sharp wide open from 150 to 400mm, great minimum focus distance of 50-180cm 1:3.1 macroish, fast hypersonic focus motor with full time manual override
The Con's: relatively slow aperture of f/6.3 from about 250mm onwards, not as sharp above 400mm, chromatic aberration and vignetting at the edge of the frame (on FX), huge 95mm front filter, focus problems on some lenses
I've only had the lens for a day and have yet to use it in the field but am looking forward to the chance to use it for either wildlife or sports when the opportunity arises and I'll definitely report back when I've had a chance to test it much more thoroughly.
Whilst it wasn't the brightest of days this morning with hazy overcast skies but I took it for a quick spin from our front balcony - all shots standing handheld with OS on shot at f/8, 1/400 and ISO 180-280, RAW images straight out of camera and converted to JPEG in Lightroom. These are pretty mundane but look pretty promising so far - looking at the 420mm and 500mm at 100% in Lightroom I can't see much if any drop in IQ.
50mm - setting the scene you can see the tops of the tree in the middle there that I'm going to zoom in on - you can't see it at this size but 50mm (at least this image) is quite soft
210mm
290mm
420mm
500mm
100% crop of the 500mm image
