Đánh giá lens sigma 18-125 năm 2024
(From Sigma lens literature) The Sigma Corporation is pleased to announce the new 18-125mm F3.8-5.6 DC OS HSM. This compact high zoom ratio lens is designed exclusively for digital SLR cameras and incorporates Sigma's original OS (Optical Stabilizer) function. This system uses two sensors inside the lens to detect vertical and horizontal movement of the camera and works by moving an optical image stabilizing lens group to effectively compensate for camera shake. It offers the use of shutter speeds approximately 4 stops slower. It is the ideal lens for several type of photography such as wide-angle, telephoto and close-up. SLD (Special Low Dispersion) glass, a molded glass aspherical lens and two hybrid aspherical lenses provide excellent correction for all types of aberrations. The super multi-layer coating reduces flare and ghosting. High image quality is assured throughout the entire zoom range. This lens has a minimum focusing distance of 35cm (13.8") at all focal lengths, and has maximum magnification of 1:3.8, making it ideal for close-up photography. This lens incorporates HSM (Hyper Sonic Motor), which ensures a quiet and high-speed autofocus. Features
*1 OS function is not available. *2 If the camera body does not support HSM motor, AF will not work. Sigma18-125mm f/3.8-5.6 DC OS HSMSigma 18-125mm f/3.8-5.6 DC OS HSM User Reviews8.2/10average of 6 review(s) Build Quality8.8/10 Image Quality8.2/10
8 out of 10 pointsand recommended by sflorio (8 reviews) Versatile, very good photos if you know what you're doing Some chromatic aberration at edges Important update: I discovered today, a year after posting the review below, that in fact this lens takes quite sharp photos wide open, but you have to focus manually, or use the slow focus in live view on a Canon. The autofocus just doesn't deliver at 18 mm f/4.0, but if you use live view you can make it as sharp wide open as at f/8. (see below) After buying my Canon xSi I quickly concluded that I was not going to be satisfied unless I had a zoom of some kind to go with it. For a walk around lens, the modest 18-125mm range that this zoom offered, which is moderate wide angle to moderate telephoto, sounded very appealing. I am not all that keen on sports or wildlife photos, so I eschewed the available super zoom lenses, not just for cost but for weight, size, and image quality issues. I waited for several weeks to see if they would ever do a test of this new OS version of this lens on this site, or for anyone else to post a review, but since that didn't happen I took the plunge and don't regret it. So now I'll post the first review: I've done pretty extensive tests on this lens, taking many tripod shots out my window in Chicago, trying different apertures and focal lengths, and comparing them to my two Canon lenses, and found it compared favorably. I found the Sigma's photos to be good looking and always in focus. The OS works pretty well, and I was able to take two perfectly clear hand held shots at full 125 mm telephoto at only 1/15 of a second, though I had to use my best technique, as I suspect at full tele it's not hard to overwhelm the OS. Two more identical shots taken without OS were both blurry. I've taken a few thousand shots with this lens so far and have no focus problems. Focus is fast and quiet. I took a number of shots of seagulls at 125mm, and every one was in focus. Here is a 100% crop example: http://farm4.static.flickr.com/3128/2639083512_53263e4092_o.jpg (This shot is cropped to remove a lot of sky. Please note that you can't get this close to a bird in flight with a 125mm, but it is still a clear photo) At 18mm this lens is a tiny bit less sharp than Canon's well-regarded 18-55mm IS kit lens that came with the camera, but as you zoom in the Sigma gets better, particularly at 50mm. Here is I shot on Flickr taken with this lens at 18 mm. Unfortunately Flickr rezzes the image down a great deal so you can't see it in all its 12 megapixel glory, but this will give you some idea. http://farm4.static.flickr.com/3235/2618470219_b5a7780817_b.jpg I will say that this lens requires you to stop it down for the sharpest images, while the Canon 18-55 IS is more forgiving if you shoot wider. You MUST stop the Sigma down to somewhere in the range of f8 to f10 for best results (using autofocus) at all focal lengths, and this makes the OS all the more necessary. I would not recommend using this lens wide open at any focal length (unless you focus manually). But once I knew what I was doing I took some very sharp shots indeed. Here's another one at f8, 125mm http://farm4.static.flickr.com/3142/2618604271_573b46b0a1_b.jpg Canon doesn't yet have a zoom for digital cameras with this same range, and the closest thing they do have, the 17-85mm, is more expensive and didn't perform all that well in slrgear.com's tests. The non-OS version of this Sigma did arguably better than the Canon in those tests, and two and a half years after its predecessor's debut you would hopefully expect this newer version of the Sigma to have at least a few refinements to the IQ, but I have no way of knowing that for sure. The telescoping part of the lens is very tightly constructed, with no looseness or feeling of imprecision at all, unlike the Canon kit lens. It has a zoom lock, but this doesn't seem to be necessary as there is no lens creep. I found this lens to be very well built and solid. This is not a light lens. At about a pound it is twice as heavy as the Canon 18-55mm IS kit lens. Still, some of the superzoom digital lenses by Sigma and Tamron such as the 18-250mm weigh quite a bit more. Overall I would say this is a very nice lens and I would buy it again. If you want the option to have one lens you can leave on the camera while travelling around, and if you're hooked on wide angle as I am, and if you also like telephoto but don't need a 200 or 250 mm superzoom and all the image quality compromises that can entail, this is the best and only choice for Canon APS-C digital cameras that I know of at this time, and I would recommend it. Update: I would like to add to the other reviewer's comment about the OS staying on for maybe a minute after the shot. This does seem to be a bit of a problem, since all the time it is on it is running down the battery. I don't know why they did this; the stablized kit lens that came with it deactivates seconds after each shot, and the battery seems to last longer with it. But I've discovered an easy workaround for the Sigma, at least with a Canon xSi: Just hit the ISO button, and the OS instantly goes silent, and presumably inactive. |