| The EF-S series of lenses, by Canon, are | | | | while ensuring superior image quality, resolution |
| exceptional lenses applicable for Canon digital SLR | | | | and contrast at all focal lengths. |
| cameras such as: the EOS 20D and Rebel models. | | | | As a member of the EF-S family of lenses, the |
| Why? The key design feature aims to match the | | | | 17-85 F4 IS USM is a strong performing |
| APS-C imaging sensor with the image circle. How? | | | | wide-angle to telephoto lens. Its list of features |
| This matching objective is achieved by reducing | | | | include: Image Stabilization for hand-held situations; |
| distance between the rear of the lens and the | | | | and is optically optimized for the digital SLR |
| focal plane, thus decreasing the size of the image | | | | camera; a ring-type USM designed for fast and |
| circle. | | | | silent auto focus. The full-time manual focus in AF |
| The result? Canon's EF-S lenses are more efficient | | | | mode is also a useful addition. |
| in terms of: weight and cost of wide-angle lenses | | | | |