Canon’s EF-S 10-22mm f/3.5-4.5 USM; An Ultra-Wide Zoom Digital APS-C Format Lens

The Canon EF-S 10-22mm f/3.5-4.5 USM (16-35mm equivalent in 35mm parlance) was designed to cover the APS-C format, specifically the EOS 20D and both EOS Digital Rebels (plus future APS-C models). Canon's EF-S lenses (S = Short Back Focus) are physically matched to these cameras. This design also results in a smaller and lighter lens (3.5" long and less than 14 oz). There is even a built-in mechanism to stop you from mounting it to an incompatible EOS camera, such as the 1D or 1Ds, and a rubber O-ring to prevent scratching that camera body in the process. The lens is also not compatible with the EOS 10D, which predates the EF-S design.

Internal movement gives this lens excellent balance. Also, you never have to worry about the inner barrel accidentally shifting position when you turn the camera downward or upward, or when pressing against a shop window to photograph the interior.

Is that a shortcoming? Is this a scaled-down Canon lens in reality? I was told by Canon that the only things stopping this glass from being designated a premier L-series lens are first, as we noted, it can't be used with the larger sensors and second, it lacks the weather-resistant construction found in current L-series optics. Beyond that, it will go head-to-head with any L lens without flinching.

Optics And Zooming
The lens also shares the circular aperture (hence the "CA" designation in Canon's literature) found on Canon's newer lenses. This feature gives you smoother out-of-focus backgrounds, down to two stops from maximum aperture. The only thing missing is Image Stabilization, but as my handheld shot inside a dimly lit church proved, it wasn't necessary.

I preset focus and moved in for this close-up, with the lens at 22mm and the built-in flash on. First, with the lens stopped down to f/8 (ISO 400), lens vignetting was not apparent; and second, there was no vignetting from the flash as well, even with the lens hood attached.
All Photos © 2005, Jack Neubart, All Rights Reserved

To top it off, optically, this lens is on a par with, if not better than, its larger, more costly L-series sibling, the EF 17-40mm. This EF-S zoom sports some fancy glass. There are three aspheric elements and one Super-UD (ultra-low-dispersion) element to give you exceptional performance for a lens in this zoom range, down to the closest focusing distance of 9.5"--at all focal lengths, no less. Physically, the only thing that bothered me was the cheesy-looking silver-tone zoom ring.

I cropped down to the bug to show the detail this lens can capture. While my macro lens could deliver a life-size rendition, this was no small feat for an ultra-wide zoom lens.

The EF-S 10-22mm zoom boasts Canon's proprietary ring-type ultrasonic focusing motor (USM). Translation: ultra-quiet, ultra-smooth autofocusing that keeps pace with my shooting style. To sweeten the pot even further, you can override the autofocus setting at any time by turning the manual focusing ring. The only time you need to set the lens focusing switch to manual (MF) is to lock in focus for a series of exposures, without having to deal with autofocusing and manual overrides each time. Lens movement is internal, so you can use a circular polarizer without fear of changing the setting as you zoom or focus. The lens features a 77mm front-mounted filter thread. That means expensive filters, should you choose to use them. But if the only reason you're buying a filter is to protect the lens, save your money--unless you're heading out into windy and sandy/dust-laden environments, where the added protection may outweigh any loss of definition the filter may produce.

In Operation
Zoom lenses are often notorious for flare and poor light transmission, because of all the lens elements and air-to-glass interfaces that light must pass through. And that makes a lens shade (hood) all the more necessary. So you would think this lens comes with one. It doesn't. Luckily my 17-40mm L lens did--and they both use the same bayonet-mount petal-shaped lens hood (model EW-83E). So, I could avail myself of this accessory immediately--and did for most of my pictures.

As I descend the escalator inside the Newport Mall (in Jersey City), the grandeur of the architecture suddenly hit me, and I had to photograph it. So back up I went, and photographed the interior with the 10-22mm zoom at 10 and 22mm. The key, again, was to keep the camera parallel to the ground to avoid distortion. Also, keep pillars away from the frame edge on either side. The right edge of the 22mm shot showed a tiny bit of distortion in a pillar, so I cropped it out.

I was glad to have that lens shade when I photographed a day lily. The protruding filaments (the reproductive organs) of the flower and the lens had a close encounter, as I tried to move ever closer, with the lens shade running interference. You know how they say that objects may be larger than they appear in the car mirror... Well, here, objects are closer than they appear through the viewfinder, so be careful when moving in for those close-ups. Because of the distance from the tip of the filament to the petals, capturing sharp detail throughout, even with a wide angle, was practically impossible. Shooting handheld, it wasn't practical to stop down and take a chance that this action would result in blurring shutter speeds. Bad enough a breeze was kicking the flower about.

You can minimize distortion effects even at 10mm by holding the camera level and shooting squarely into the scene. Find some reference points, and use the viewfinder frame and focusing indicators to help with alignment. Shooting in the street, while watching for oncoming traffic, prevented me from using a tripod.

Then at one point, a bug landed on the flower. I held the camera to my eye, moving slowly and patiently past a neighboring stalk, with the lens at 22mm (10mm was just too wide for a full-frame close-up). As I normally do when shooting close-ups, I set the lens to MF and manually set focus to the closest point, then physically moved to and fro until the bug was in focus. And snapped the picture.