Sigma 885101 18-200mm F/3.5-6.3 DC OS HSM Lens for Canon, Black

Product Information

In short for days out or holidays where convenience is preferred to ultimate quality, and you wont miss shots lens changing it fits the bill admirably. Flare is well-controlled overall, but shows up stronger at the longer end of the focal length range (where the lens hood is less effective). A petal-shaped hood is supplied as standard with the lens, which does a good job of protecting the front element from extraneous light that may cause unwanted flare and loss of contrast. During testing there were no issues with flare and contrast holds up well, even when shooting into the light. A lens hood is supplied in the box which you can attach by lining up the markings on the lens. You can switch it around to face the wrong way when storing the lens or camera with lens attached. Distortion is usually invisible, but if you have a straight line running along an edge, you may see it. The photo above shows it at its worst, and unless you're shooting buildings for a living, not as bad as I make it out to be.

Falloff of illumination towards the corners is reasonably well controlled. At 18mm the corners are 1.42 stops darker than the image centre and at 200mm the corners are 1.26 stops darker. Visually uniform illumination is achieved with the lens stopped down by just over a stop from maximum aperture throughout the zoom range. Shooting wide open at 18mm, sharpness in the centre of the image area already approaches very good levels, and clarity towards the edges of the frame is fairly good. Stopping down the aperture improves sharpness across the frame, peaking between f/5.6 and f/8, where sharpness in the centre is excellent and towards the edges it reaches very good levels. The focusing ring is mounted near the front of the lens, with a rubber ridged knurl that is easy to turn. The lens really isn't built for manual focus: the ring is only a quarter-inch in width, and doesn't offer much in the way of travel for manual focus operations (much less than a quarter turn). The ring turns during autofocus operation, and can't be overridden in this mode: you must specifically disable autofocus to override the focus clutch.I bought this lens to replace the kit lens of my EOS 300D, and it outperforms it in every domain. This focal range is extremely convenient as a walkaround lens and perfectly suits my needs (but I'd love a wider aperture too...).

With a reproduction ratio of 1:4.2 (0.24x), the 18-200mm has fair macro capability, but it won't replace a macro lens any time soon. Its minimum close focusing distance is 45mm (just under 18 inches). By 24mm, lines are nearly straight again, but pincushion distortion sets in by 28mm and gets relatively strong by 50mm through 200m. After shooting several thousands of photos over the past two months, I have found the 'standard' of f8 through f11 to be the optimum aperatures across the entire focal range. No surprise there. But, you can still use a faster f stop with good results. Especially with the K10D which features a sensitivity shooting mode, and image stabilization is built in. Take complete creative control of your images with PIXMA and imagePROGRAF PRO professional photo printers.

Ease of Use

A slightly curious scale on the outer sleeve of the 'double trombone' zoom mechanism shows the image magnification when the lens is set to 0.45m (i.e. the minimum focus distance). The numbers correspond to each of the focal lengths marked on the zoom ring except for 18mm (at which position the barrel is fully retracted, and this sleeve is not visible). Other focal lengths have different maximum apertures. At the longest focal length of 200mm, the maximum aperture is f/6.3 - here there’s quite a significant amount of light fall off around the outer edges of the frame, which persists into f/8.0, and is almost gone by f/11. Depending on the subject you’re photographing you may or may not notice the dropoff.