Courtesy Of Rick Decker |
Flare and CA seem to be well controlled. Gone are the days when you would have comets streaking across your image whenever the sun was anywhere near the lens (15-30 and 20-40 among others). I took a dozen shots up at the sky at 18mm, putting the sun around the edge of the image at different positions. Seven shots were completely flare-free. What flare I was able to find was small and diffuse. A worst case scenario is posted in the sample gallery. There is some CA but not more, and probably less, than would be expected with a zoom of this type. OS: Sigma has put a new version of OS in the lens. They are not making any specific claims (as Nikon is doing with their new lenses) about how many stops you gain. I am not the best hand-holder in the world. I was able to consistently get reasonably sharp shots down to about 1/10, 1/8 and even 1/6 a second at 50mm and a distance of about 25 feet. Slower than that and the success ration went down. I actually got sharp shots at as slow as .3 and .5 seconds but the ratio was very low. In general I am very pleased with the performance of the OS. It has come a long way from that of the 80-400. The OS does appear to shorten battery life noticeably although I have not really analyzed this and my batteries are very old and well-used. OS should not be left on when you are shooting on a tripod. I would also recommend turning it off when you turn the camera off. Infra Red: I shot a number of IR pictures with the lens. The lens can exhibit a hot spot at times although in most cases, it was more like a warm spot and easily correctable. I asm surmising that some of tne coatingon the newer lenses, and not just Sigma, tend to be prone to a hot or warm spot in the center. Auto focus worked very well even with an 830 IR filter which is the stronger of the different varieties. Sharpness: Not quite as sharp as the comparison lens (the EX version) which is to be expected. It can lose sharpness a little more quickly as you move off the center. On the other hand it holds up very well at all focal lengths and f-stops - even when wide open. From my limited experience with the kit lens, the OS is a much better performer and there is no comparison. The comparison images (to the 2.8 EX) will give a good idea of what to expect. Sample pictures can be seen at: Samples I have the older non-macro version of the EX so comparisons are to that version. I took shots wide open and at f8 at 18, 30, and 50mm. All shots were AF and tripod and I picked the best of two at each f-stop and focal-length combination. Generally AF hit it right on. The comparison gallery can be seen at: Comparisons To EX Sigma has 3 great lenses in the wide-to-mid range: the 18-50 OS; the 18-50 f2.8 EX and the 17-70. Having shot them all extensively, it is no easy choice on which to buy. If you are prefer to hand-hold whenever possible or shoot often in low light, the OS version is a no-brainer. If you are shooting lots of close-ups and/or portraits and want minimum DOF, the 2.8/EX should be your choice. It is generally considered the sharpest in the group. If you want a little greater range and are doing landscape a lot or you want the best macro capability of the three, then the 17-70 has the edge. With either 3 you can't go wrong. The OS lens carries a price tab of $300.00 at B&H right now. Without a doubt this is a great lens for the money and I would say buy it now as it wouldn't surprise me if the price goes up in the near future. If you have any questions or need more information you can email me at Rick Decker |