Let me say straight away that I know expensive Nikon lenses are unbeatable on Nikon cameras. So don't go throwing test graphs and data sheets at me. But I've found the paying guests at our parties and events don't care what lens is used as long as it's a great photo. We've stopped taking the really expensive lenses to Events as they get damaged, are extremely heavy, and basically overkill.
I brought a Sigma 24-70mm lens at Xmas to use on my backup Nikon D700 as we were so busy with Xmas parties I needed a second photographer to help. I ended up using it myself and letting the other guy use my pro Nikon glass. The Sigma is lighter and when you are printing 9" x 6" photographs there is NO difference in quality! In fact it focuses just as fast and is as sharp as the Nikon.
I've now been appointed official photographer for our local Cricket team, and am working with Herts County Cricket to shoot the U-16's in action as my son is in the squad. I've also just been asked to cover all the sporting events for the local private school, so will be shooting Football, Rugby, Cricket, Lacrosse and Netball and more.
Obviously we will need a team of photographers to cover all this so I priced up a kit for each photographer based on a D700 camera, WT-4 wireless transmitter to send the images back to our Mitsubishi Click, spare batteries, memory cards etc. The stumbling block was the lenses. Nikon glass was out of the equation, and I was very happy with the Sigma 24-70mm.
So I brought a new Sigma 150-500mm imaged stabilised lens to try out. I've used every sports lens going for both Canon and Nikon, usually renting them for events as needed. The Bigma is a well respected lens at 50-500mm but is too slow and lacks image stabilisation. So the Bigos looks ideal with it's clever Optical Stabilisation with two modes for monopod use and hand held.
I've tried getting away with 200mm and 300mm lenses in the past for Sports, using doublers, and know that for the photos I want I need at least 500mm. The logic there is that you need 10mm for every meter, and the pitches are big! I'm never more that 50 meters from the action, so 500mm gives me the range to get a full frame photograph of an individual which we can then offer framed. I'm not too worried about blurring the background, it looks nice and can isolate a sportsperson from a busy background of spectators, but I'm not working in packed Stadiums with huge crowds (yet:)
I've found the Sigma 150-500mm performs well. I tested it in sunny and overcast conditions and it gets the shots I want. I'm not posting any yet as they are of U-16's but once I've got permission they will be in a gallery called "Sport" on the website. The lens is not too heavy, zooms smoothly and the image stabiliser works really well. I've used all the different focussing modes on the D700 and prefer the central focussing mode to the 56 point 3D mode which sometimes locks on to the wrong competitor.
Colours are vivid and accurate, there is no problem with chromatic aberrations or lens flare, not suprising really when you see the size of the flowerpot lens hood included. The lens is big and really looks the part, the parents at the matches I attend often give up and put their SLR's away when they see I'm shooting, exactly what we want to achieve! I tend to shoot away in full manual with auto ISO turned on in case the sun slips into a cloud. Looking at the shots I've taken I'm mainly at f8 with shutter speeds around 1/500 to 1/1000 which freezes the action nicely.
The low light capability of the Nikon D700 kicks in often, some of the shots with auto ISO end up at 1600 or even 3200, but there is no grain or noise unless I really crop heavily, but if the shots are properly framed there's no need to. I leave white balance at auto and keep the quality at Medium Jpeg with optimal quality turned on in the hidden menu. That ensures the images get sent quickly through the air to the Base station, and that when we have thousands of images the separate viewing stations don't slow down as parents are searching through the images. We still have more than enough resolution to crop if needed, with plenty left for a 9" x 6" print at 300dpi.
At around £700 on the street these are affordable professional lenses that every photographer should consider. I got mine from SRS Microsystems in Watford who were extremely helpful. They let me test the lens thouroughly in the store and outside in the High Street. The lens focuses down to just over a meter so you can get stunning close-ups. I've even shot team photos and informal portraits with this, couldn't be bothered to switch lenses so just moved back (a lot!) and have been impressed with the results, no distortion and beautiful perspectives with accurate depth of field. You really can focus in on an eye and let the lens and camera do the rest.
So in summary it's a stunning lens ideal for Sports and Wildlife which is beautifully built and feels natural to use. I'm really happy and will be kitting out the team.