words and image source/photographer : Eksovichea Tito Hak

This lens more commonly comes as part of a kit, but it can also be bought on its own as an aftermarket option. Generally quite a sharp EF-S kit lens specifically designed for digital crop sensors. So 17mm is 17mm with this lens just as 85mm on this lens at the tele end is 85mm when used with a crop sensor Canon dslr. Its technically and physically one of the better examples of an EF-S kit lens when compared to the 18-135mm version and the 18-200mm version. But for what it lacks in zoom reach when compared to the others it makes up for in optical image quality.

Barrel distortion is quite pronounced at the widest angle of 17mm, but its hardly anything to be bothered about since nearly all wide angle lenses exhibit a significant amount of barrel distortion by default. I don't even know why they bother mentioning it like it was a bad thing since its not like you could get any different as standard, its something that has always been inherent of wide angle lenses and also at the wide angle of zoom lenses that are relatively wide. Generally the wider you go (allowing you to fit more in the frame) the more barrel distortion you generally get. Fortunately the most recent Canon dslr's are all equipped with on board distortion correction if required, and if you have access to Photoshop you can even tweak it a little further if you feel the on board correction wasn't enough. Personally I reckon barrel distortion can also at times be a desirable optical trait for a more artistically dramatic visual effect for certain styles of photography. 

As you move through the zoom range the distortion becomes less apparent, anything beyond 24mm becomes significantly less barrel warped, and gradually more so as you move further.   

Starting at f4 generally helps towards this lens achieving its sharpness, however even with image stabilisation this does mean that its noticeably slower at the widest angle than say an 18-55mm kit lens with IS that starts out at an aperture of f3.5. So even without blurring from camera shake the shutter speed would still have to be set significantly slower for low light conditions in order to try and achieve vastly lower grain images at lower ISO's for none flash assisted photography. The I.S. in this case won't help you at all with moving photographic subjects without flash assistance in low light conditions. 

Build wise its plastic but feels extremely solid, robust and weighty.

It has an Ultrasonic motor meaning its extremely quiet.

As mentioned before it has image stabilisation which works great for eliminating camera shake, but it won't help you with moving subjects in low light conditions when working without a flash. However if you're generally going to be shooting still images in daylight where its always sunny, and/or will be using it mainly for flash photography, none of the potential low light slow speed issues will be of relevance as you'll most likely get impressive results with this lens in combination with the appropriate photographic vision and ability to use the camera properly.