Canon EF 100mm f/2.8L Macro IS USM Construction, Performance, and Image Quality

BUILD AND DESIGN

Lens Mount
The 100 macro features the Canon EF lens mount which had been the brand standard since replacing the FD mount in 1987. Simple enough, but then Canon muddied the waters a bit and introduced the EF-S variant of the EF mount in 2003.
The EF-S is designed for 2003 and later cameras with APS-C sized sensors resulting in 1.6x crop factors. Cameras with EF-S mounts can accept both EF and EF-S lenses, but EF-S lenses can only be used on EF-S mounts. EF-S lenses have a rubber ring that prevents their being inadvertently installed on an EF mount camera (and causing lens and/or camera damage in the process). Additionally, EF-S lenses use a small white rectangle as the lens alignment mark; EF lenses use a small red dot. EF mount camera bodies have the red dot on the mount; EF-S bodies have both the white rectangle and red dot. Long story short: the 100 macro can go on any Canon digital body.

Construction
The macro 100's lens mount is metal and the barrel is composite - there are 15 glass elements arranged in 12 groups, including a single ultra low dispersion glass element. Super Spectra coatings help reduce ghosting and lens flare and the circular diaphragm is nine-bladed. Aperture size is established electronically via the camera body - there is no way to open or close the diaphragm manually. The front element does not rotate and accepts 67mm filters; focus is internal and there are dust and water-resistant seals typical for "L" class lenses. The distance scale is good sized and easy to read and lens controls are simple and easy to understand. Here's a look at those controls (note the red alignment dot designating an EF lens) and the distance scale.

Canon provides a hood and carry bag with each lens.

With an MSRP of $1050 USD, the composite lens barrel was a bit of a surprise, but build quality looks good and feels generally solid. When you consider that as much as 50% of the Boeing 787 primary structure - including the fuselage and wing - will be made of composite materials, having a composite lens barrel seems a fairly tame application by comparison.

Handling
With its fixed focal length, the 100mm macro will shoot like a 160mm lens (35mm film equivalent) on Canon bodies with a 1.6x crop factor; 100mm on full frame Canon bodies and at 130mm on the 1D Mark IV we used for this review. Close focus distance on the lens is 12 inches (to be technical, 0.99 feet) from the subject to the sensor focal plane; distant focus is infinity. The lens permits focus ranges to be compartmentalized - 12 inches to infinity (full), 0.5 meters (19.7 inches) to infinity or 0.3 meters (12 inches) to 0.5 meters. Setting the focus range can sometimes improve AF times as the lens doesn't "hunt" through the distances that have been excluded.

When used as a modest telephoto for distant shots the 100 macro's stabilization system can provide up to 4 stops correction - moving in to macro distances up to 2 stops are available at 1.0x magnification. Before the existence of stabilization, the rule of thumb for a shutter speed to produce a sharp image (minimize camera shake) while hand holding the camera was the inverse of the focal length of the lens - for a 100mm lens you'd like to be able to shoot at 1/100th of a second. With the 1D/100 macro shooting at 130mm, we'd like to have 1/125th of a second or more without stabilization - but how low can we go with stabilization active? Since Canon rates the stabilization of the lens for up to 2 stops of correction, that suggests we can shoot in the vicinity of 1/30th of a second when doing fairly close macro work. Here's a hand held shot of Delta in low light at 1/20th of a second with the point of focus the hairs just adjacent to the eye.

How low was the light in this instance? It took bumping the ISO to 1600 to get that 1/20th at wide open aperture.
Because of the critical focus and minimal depth of field issues prevalent in macro photography, particularly where the lens is being used near its minimum focus distance, serious macro enthusiasts would traditionally use a tripod or some other form of camera support to position their camera, fire the shutter with the self-timer, cable release or remote control to minimize shake by eliminating human touch, and often lock up the camera mirror before taking the shot to help remove any last vestige of shake.

Here are two tripod shots to illustrate the depth of field issue - the turquoise bracelet is curved so the edges are farther from the focus plane which was near the top center of the bracelet. The shot at f/4 has minimal depth of field and the edges are out of focus. The shot at f/32 picks up some additional depth of field and the edges are much more in focus. Shutter speed for the f/4 shot was 1/100th of a second, while the f/32 shot took 1.7 seconds.

f/4

f/32

The Porsche badge illustrates the focus/depth issues from top to bottom on the image - water droplets at the top are fairly sharp and in fact you can see the fine metallic grains of the paint reflected in them. The badge itself looks fairly sharp overall, but close examination shows the top is a bit softer than the middle and bottom of the badge. The focal plane here started pretty close to the paint at the top of the image and then angled slightly upward (or stayed straight as the hood and badge curved slightly downward) so the middle and bottom of the badge look sharper while the water droplets are softer than those at the top. This shot was hand held at 1/30th of a second, so closing down the aperture to gain depth of field (and lose shutter speed) wasn't an option. Bumping up ISO would return shutter speed with smaller apertures, but then noise may become a concern with cameras that don't perform well at higher ISO sensitivities.

With Canon already fielding a 100mm macro EF lens that generally got good marks for image quality, the development of the new stabilization system became the raison de etre for the "L" series 100 macro. The new lens (which replaces the non-stabilized, non-"L" series macro) won't eliminate the need for tripods or other camera support for the most critical close-up work, but it definitely expands the hand-held macro envelope.

Mounted on the large and heavy 1D mark IV body the 100 macro balanced nicely and was pleasant to use. Its length and weight (4.8 inches without hood, 22 ounces) might be a bit much for lighter, smaller bodies, but a fair chunk of that weight is concentrated toward the rear (mount) end of the lens which will put in proximity to the body and should help balance.

PERFORMANCE

Auto Focus
AF with the 100 macro on the 1D Mark IV was quick and generally accurate in good to low lighting conditions. I tended to use the single shot mode for static subjects and AI servo for moving ones.

Manual Focus
The manual focus ring on the 100 macro is wide and smooth - rotation through about 140 degrees is required to go from close focus to infinity. For critical close up work the only viable method is to manually focus to whatever point you want, then move your upper body and the camera slightly to and fro to return to the precise focus point rather than hold the camera with one hand and try to always change focus with the other. If you're backed off from the subject a bit, traditional manual focus works fine.

Image Quality
Image quality is - in a word - excellent! Close up or at a distance. I set the 1D to the highest image quality JPEG for the shots with the 100 macro - all other camera settings were at default except for ISO which I manually set depending on the situation. Here's a shot of the block wall I use to check for various lens distortions - lots of straight lines and good sharpness throughout the frame, corners and edges included.

Shots that would typically display chromic aberration in lesser lenses were clean with the 100 macro - Canon has done a good job in this department.

Back when we all shot 35mm film, the "portrait" lens focal length was generally accepted to run between 85 and 135mm - with my preference being for 105mm. With the 1D/100macro combination shooting at 130mm, we're right at the top edge of the portrait window - here's Amy after a morning surf session.

That 130mm length lacks true telephoto "punch", but it gets you a little closer to distant subjects. Police lines wouldn't let me get any closer to this salvage operation, but the distant shot cropped to 12x8 inches and 300 dots per inch eliminates a lot of open space, and after fudging past the yellow tape briefly I got close enough for a more detailed look at the recovery.

Original

Cropped

Here's some other shots of a decidedly non-macro nature.

The capability to shoot macro without some of the traditional tools for camera stability will be a major selling point for this lens, so I left the tripod in the closet for the hand held close ups that follow. Here's where the difficulty achieving the critical focus and depth of field needed to produce an evenly focused image without resort to camera support and painstaking adjustments can be truly appreciated. We're dealing with the lens needing to be perpendicular to the subject, but in two axes - from side to side and top to bottom - and this only works if the object is perfectly flat and the hand holding is precise.

Finally, I bumped the ISO to 6400 and aperture to f/16 to shoot the 1:1 images of the watch and the baseball hat. I'm fairly happy with the hat 1:1, not so much with the watch 1:1, but both were the best I could do. Shooting at lesser magnifications is a breeze compared to trying 1:1, but even that was possible with the right settings in the lens and camera.