This lens was a permanent fixture on my Nikon D70 from November 2005, then spent time on my D200.
Initially I had my doubts about it – there seems to be a real learning curve involved in getting the best out of the lens.
Now that I am used to it, I have nothing but praise for it.
Starting with what makes this lens stand out from the crowd, the obvious selling point is the in-built stabilisation (OS in Sigma-speak).
Gyroscopes within the body of the lens suppress unwanted camera/lens shake, and it really works.
The system takes a second or so to spin up to speed (which caught me out when I first started using the lens) but it does this while acquiring focus, so there is no a problem there.
While I agree that good hand holding technique goes a long way without stabilisation, I am in absolutely no doubt whatsoever that the extra help provided by those gyros can make all the difference.
This can mean the ability to use a lower shutter speed, smaller aperture of lower ISO (or any combination of the above) and still get sharp shots; or – and this is the true advantage of OS in my opinion – it allows you to pull worthwhile shots out of the hat in really marginal conditions which you might not get otherwise.
So it might not be an essential, but I for one would not want to be without stabilisation when shooting handheld.
It has two stabilisation modes (three if you include off!)
Mode 1 deals with horizontal and vertical movement – ie normal use – and mode 2 compensates for vertical movement only, supposedly for use on moving subjects, motor sports and the like.
Mode 1 is the only only option I use – I might switch the stabilisation off if I am panning – but the option is there is you want or need it.
Unlike some of the newer Canon stabilised lenses, the Sigma stabilisation needs to be switched off if you use it on a tripod.
OK, enough about the stabilisation…
The optical quality of the lens is excellent.
Like many lenses, it seems to be sharpest stopped down a tad (mine lived at f/7.1), and I had no concerns at all about using it at 400mm on my D70, in full expectation of sharp, well saturated, contrasty images.
Sharp throughout the 80-400mm range though, it was also useful for impromptu landscape shots at the short end.
A versatile lens, then.
It has a twist mechanism for extending the body (like the Nikkor 80-400mm VR and unlike the push-pull of the Canon 100-400mm USM IS) and has a lock button (which only works at the short end) to prevent lens creep – the lens extending under its own weight when moving around.
I have to say though, that lens creep was not a problem with my lens.
In good light it worked quite well with a Kenko Pro 300 DG 1.4x teleconverter, and I could get OS and AF (albeit slowly), but the lens was definitely happier on its own.
At 1.75 kg (3lbs 14 oz in old money) you couldn’t describe it as a lightweight, but I routinely carried it and the D70 around on a neoprene strap for several hours without any problems.
The Nikon-mount version of this lens has a built-in AF drive motor rather than relying on the drive in the camera body which made it fast focussing for a non-sonic drive lens (noticeably faster than the Nikon 80-400mm, which relies on the in-camera AF motor) and I had no problems on that score: but with a sonic motor it would be unbeatable, IMHO – and I bet that the next version of the lens has the Sigma Hyper Sonic Motor or “HSM”.
The lens might give the impression that it makes a bit of noise when focussing, and yes, it is louder than an HSM lens – it has to be, as there are gears being driven.
But the truth is, the noise was noticeable only because the source is only a few inches from your ears when the camera is in use: hold the camera at arms length, activate the AF, and the motor noise is little more than a whisper – not remotely loud enough to disturb the bird.
Not the fastest lens out there, making it an F/4 would add considerably to bulk, weight and cost and would take it straight out of the unique niche it is currently in (at the time of writing this was the only Third Party lens providing 400mm and stabilisation).
In my experience then, the lens delivered everything I could reasonably expect of it: it is versatile, it provides great image quality, the OS does precisely what I want it to do… and all in a convenient, manageable package.
In an Ideal World it could be faster (in both senses of the word – an F/4 with HSM would be spectacular) but, given that much the appeal of the lens lies its relative compactness and ease of use, I was more than happy with it as is.