The Zuiko Digital ED 9-18mm f/4.0-5.6 is a lightweight, compact Four Thirds lens gets the What Digital Camera review treatment...
The zoom action condenses the Zuiko’s barrel then extends it again as the focal length is varied but the amount of movement is very small. There is a very pleasant tactile rubber grip on the zoom collar, which is located in the middle of the barrel and occupies almost half of its length.
Despite not being identified as such, the Zuiko Digital is fitted with an internal focusing AF mechanism that leaves the manual-focus ring undisturbed when AF mode is selected. The zoom’s AF performance seems a little sluggish on the E-3 body used for this review but the ability to use manual focusing in AF mode is a useful touch.
Inside, the zoom employs both low-dispersion glass and an element that has an aspherical profile on both surfaces, designated as a Dual Super Aspherical (DSA) element. Such is the zoom’s design that it can focus to within 14cm of the object according to an Olympus white-paper although the zoom’s own data sheet states 25cm. I measured around 12cm from the front element at closest focusing. Whatever the correct figure is, this zoom’s close-focusing performance is truly exceptional and offers some unusual creative possibilities.
The Zuiko Digital’s MTF curves exhibit a lack of smoothness but this is not a serious issue. For optimum results the lens should not be stopped-down below f/11 and the MTF figures hardly go above the 0.3 cycles-per-pixel line, but these too are only minor niggles. More serious is the slight softness that was seen in some real-world pictures.
The lack of focused distance read-out might also offend some users, but none of these things is an unacceptable limitation for a lens that is so capable and yet so very keenly priced.