- Compact and lightweight
- New optical design with 13 lenses in 11 groups
- Versatile focal length range
- Four-stop image stabilizer
- Super spectra coating minimizes flare and ghosting
- 25 closest focusing range
- Smooth focusing with new STM motor
- Circular 7-blade aperture
- Non-rotating front element
- Improved manual focus ring
Canon FE-S 18-55mm f/3.5-5.6 IS STM was first announced on March 21, 2013, along with Canon 700D/Rebel T5i and 100D/Rebel SL1. The new lens has a different optical formula and includes Canon’s STM technology (stepping motor) that claims to offer quieter continuous autofocus when shooting video. The lens also has an internal focusing design. It has also been included as one of the two alternative kit lenses for Canon 70D.
Design and Performance
The lens weighs at around 205g and measures at 75cm in length which makes it one of the most compact and lightweight standard zoom lenses that the company offers. As the lens is an all electronic EF-S mount lens, you can only use it with Canon’s DSLR range having APS-C sensors. Despite the plastic exterior, the build quality of the lens is fairly solid. It has a semi-glossy black finish with slight stippling. Considering the pricing, we should not expect something out of the box when it comes to the build quality.
Coming to the design, the lens has a completely changed design with an addition of two new groups of lenses (13 lenses in 11 groups). The lens also gets an additional seventh diaphragm blade which we presume is to improve out-of-focus elements. The focusing ring is quite narrow with a ridged, rubberised grip band that is easy to turn. The lens is around a quarter of an inch in width.
There are no stops at either the infinity or the close-focusing end that lets you know the limit of focus. Moreover, now the ring no longer turns during the autofocus operation. As the full-time manual focusing is now available, you don’t have to switch over to the manual focusing mode to fine-tune focus. Unlike its predecessor, the lens sports a non-rotating front element, so the filters will remain in place during the focusing action. It accepts 58mm filters that are made of plastic.
The width of the zoom ring is at over an inch and a quarter. It has a rubberised texture that provides an easy grip. The zoom action is pretty smooth and it takes a 70-degree turn in going from 18mm to 55mm. It adds an extra 3/8’’ to its overall length when it is zoomed out.
As claimed by Canon, the lens boasts image stabilization that has an advantage of up to four f-stops (at 55mm) over the lenses without a stabilizer. This can be activated by a Stabilizer ON/OFF switch that is placed on the side of the lens. Canon’s new IS technology is also capable of detecting intentional panning movement and can automatically switch to the Panning IS mode from the Normal IS mode. There is also a switch to enable or disable the autofocus (“AF/MF”). The optional EW-63C bayonet-mount petal-shaped lens hood reverses onto the lens for optimum storage. The smooth black finished interior looks classy. The overall length of the lens is increased by about half of an inch when you attach the hood.
Autofocus: The improved focus system of the lens is worth every single penny of the increased price (over IS II). Unlike the IS II that made an apparent autofocusing sound, IS STM offers fast and much silent autofocus operation. So, you need to keep the lens next to your ear in a quiet room to hear the click sound that the autofocus makes. The lens now focuses internally. Also, it sports a non-rotating front element. We feel that the absence of extension is good and what is more appreciating is the presence of fixed front filters.
The lens system has a deep depth of field (DOF). The STM AF is sensibly designed to allow continuous autofocus during video recording. Though this feature works pretty nice, but you can’t expect it to focus a very fast moving subject at a close distance. The performance is much better with slow motion subjects and the autofocusing before the video recording is of much help. Moreover, the subjects do not significantly change their sizes during focusing.
IS STM has a full-time manual (FTM) focusing. Well, it took us some time to understand this feature. The thing is you need to halfway press the shutter release to enable the manual focusing option after autofocus lock. You need to set the lens to manual focus mode (AF/MF switch) to ask the camera to manually focus. Apart from this, as you change the focal length, the subject no longer remains in focus. If the camera is in sleep mode or powered off, adjusting the focal length leads to a much out of focus subject. And the lens automatically adjusts the focus when the camera is awake or powered on.
Sharpness: We tested the Canon EF-S 18-55 f/3.5-5.6 IS STM with EOS 700D. Though, the edges were not as sharp as compared to the center with f/5.6 to f/11. We found the center sharpness to be pretty high from f/4 to f/16. However, diffraction started to peep in set the aperture to f/16 and f/22. The performance improves as we tried to zoom out the focal range at 35mm and f/8 combination. Unlike the previous version, the lens performs remarkably better at 55mm than at 18mm. We found a very good sharpness at f/5.6 (variable aperture starts). When we stopped down at a combination of 55mm at f/8, we got some tack-sharp results.
Chromatic Aberration: You don’t really get an excellent performance related to CA in the wide-angle kit lenses. Same goes with IS STM. It shows a noticeable amount of chromatic aberration until you get to the long end of the focal length range. The chromatic aberration in this lens shows up as purple fringes in the high-contrast areas. Though, it can be corrected in post-processing. While the CA is always there in the corners, it is most notable at wider angles.
Vignetting: Corner shading is most prominent when you use the lens at its widest aperture (f/3.5) and widest angle (18mm). Apart from that, when you use the lens wide open, you will notice slight corner shading. The vignetting improves to almost being absent as you set your lens to f/8.
Distortion: 18-55 IS STM has a strong barrel distortion at 18mm. The problem with barrel distortion (also called pincushion distortion) is that the straight lines in the image come out as curves. Also, the sizes of the subjects get distorted with center-of-the-frame subjects looking larger. However, these distortions can be corrected with certain software. The distortion level improves as you zoom in the lens, and is almost negligible at the 55mm end.
Macro: The lens is not really a macro one. But has a decent macro capability with a reproduction ratio of 0.36x (maximum at 55mm). The lens has a minimum close-focus point of 25cm.
Bokeh: The lens gets a pretty food upgrade in the bokeh (a term used for out-of-focus areas of an image) feature. With an iris diaphragm of 7 circular blades, the out of focus points remains relatively smooth and circular-shaped even with stopped down aperture.
Should You Buy this Lens?
Priced at $249.99, Canon EF-S 18-55mm f/3.5-5.6 IS STM is not only designed for capturing a high-quality image and video shooting but also packed with some good optics, image stabilization, and AF. It has optimized lens coatings that lead to an excellent color balance.
The seven-blade circular aperture gives soft and beautiful backgrounds. The lens also complements the Movie Servo AF feature with a six-group zoom system. Overall, the lens is compact and versatile with a nice set of features.