Friday, November 27, 2009

Canon EF 100mm f/2.8 L IS USM Macro review

Canon already has a nice 100mm macro lens in the EF 100mm f/2.8 macro, so it came as a bit of surprise when Canon launched a new macro lens with the same focal length and aperture. The new Canon EF 100mm f/2.8 L IS Macro is expected to sell alongside with the original macro lens, albeit with a significantly higher price tag. What’s with this new lens that justifies a price premium over the existing lens?

Canon is positioning this lens as a premium professional quality lens with the L designation, so one should expect superior performance over the already excellent non-L macro lens. In addition, the crowning glory is the integration of a new Hybrid Image Stabilization technology into the new lens, which Canon claims will improve the percentage of sharp images when hand-held. Unlike conventional IS in other lenses, the Hybrid IS compensates for angular and linear shifts when one is shooting in macro, so it is supposedly more effective than the usual IS technology when shooting close-ups.

So is it really worth the extra money? Read on!

Built-quality and design

The built quality is excellent, as one might expect from the “L” professional lens designation. The crinkled finish is a nice touch, BUT it’s not metal as one would expect. Instead it’s really high quality polycarbonate finishing, so the lens is much lighter than one would expect from the looks. Initially I was disappointed by the realization that the lens is not metal in construction, but upon using it one would appreciate the built-quality and the balance of the lens on the camera.

Every other aspect is built to the usual high Canon quality. The switches are firm and not easily knocked out of position on the move, and yet offer a tactile click. The lens is weather-sealed at the mount area, which makes sense for nature photographers bringing the lens out to the field. The filter size is a sensible 67mm, although I don’t see myself using filters on this macro lens other than a polarizer perhaps.

The lens is fully internal-focus (IF), so the front does not rotate or extends. My older macro lenses do not feature IF, and it can be frustrating if you’re shooting really close-up and end up blocking your side lighting as you focus closer. As mentioned earlier, the lens balances nicely on the camera, which is a huge plus-point if you intend to shoot hand-held. Measuring just 123mm and 625g, it handles well in the field and will not take up much space or weight in your bag.

The lens hood is extremely deep and well flocked, and that makes it very effective against any potential flare. And while it’s rare for autofocus lenses to be well-dampened for manual focusing, it is critical for macro lenses as a lot of fine-tuning of focus takes place during close-up shooting. In this aspect, the EF 100mm Macro L IS succeeds admirably with both a well-positioned and generous focusing ring, as well as a superb focus feel with the right amount of damping.

One area that I feel is worthy of mention is the window where the focus is shown. Canon has included the magnification ratio within the window alongside with the focus distance. Now this may not be a big deal with photographers shooting macro casually, but for scientific applications and some commercial jobs requiring specific magnification ratio, this saves a lot of time and effort. Now only if there’s someway for Canon to incorporate this data into the EXIF data as well, that’d be really cool.

The EF 100mm Macro L IS lens focuses from 30cm all the way to infinity continuously, which is a long way even with the Ultrasonic Motors. Fortunately, Canon has incorporated the Focus Limiter switch on the lens which allows for not just two, but three focusing range. You can set it to 0.3-0.5m if you’re shooting only close-ups, or 0.5m to infinity if you do not intend to shoot that close, or set it to full if you want the ultimate flexibility.

Focusing speed

The EF 100mm L IS Macro features the ring-type Ultrasonic Motor (USM), which delivers high-speed focusing and full-time manual override. Compared to the older model without USM (which I was using for the longest time), the new lens is incredibly zippy. Performance is typical of the Canon USM (which is quick!), but this lens tends to hunt a bit more due to the wide focusing range of a macro lens. Use the 3-step focus limiter, and things immediately become much more positive. The USM is a welcome addition, and I found myself relying on the autofocus to attain the focus quite frequently, and using the focusing ring if I wanted to fine-tune the focus on specific aspects of the image. As mentioned before, the dampened focus ring of the lens is great, and it doesn’t feel too sloppy like many lenses.

The EF 100mm L IS Macro delivers one of the best bokeh I’ve ever seen, ranking alongside legendary lenses such as the EF 85mm f/1.2 L. The transitions are smooth and creamy, while the areas in focus remain crisp and sharp even wide-open. Foliage usually causes much problem for bokeh because of their complex structures, but the EF 100mm L IS Macro comes through the test with flying colours.

Aperture range/blades
The EF 100mm L IS Macro stops down from its maximum aperture of f/2.8 down to f/32, like many other macro lenses. There’re a total of 9 blades, which stops down nicely to a circular formation. That probably accounts in part for the amazing bokeh of the lens. There seem to be another (permanent and immovable) layer of blades that forms a completely round circle in front of the aperture blades, which I’m not certain of the function.

Chromatic aberrations/diffraction
There are slight chromatic aberrations around the bright edges in the images, although they are slight enough not to cause any problems in 90% of the cases. The very slight purplish sliver can only be seen when one scrutinizes the images in full magnification on the screen, and comparatively speaking the EF 100mm L IS Macro performs very well in the real world.

The diffraction issue is more troubling, with the images becoming mushy when one stops down beyond f/22.  Diffraction is an optical physics law, rather than the fault of the lens design. It happens on all lenses, but I have to show it as part of the lens test. It looks bad here because it’s magnified 100% (and the test images show foliage which is tough to render on a Bayer matrix sensor with anti-aliasing filter), but in real world conditions it is much less visible (we don’t usually stop down beyond f/22 most of the time).

Effectiveness of Image Stabilizer

The Hybrid Image Stabilizer is Canon’s much hyped advancement in the arena of macro photography. Designed to stabilize both angular and linear shifts, the Hybrid IS is optimized for close-up photography. I conducted the stability test with two scenarios – handheld without IS and handheld with IS.

So how does the Canon EF 100mm L IS Macro fare? Pretty impressive! Without the Image Stabilizer, the average lowest shutter speed which I can consistently handhold without significant image blur is 1/50th second . Turning on the IS, I can handhold steadily for sharp images down to 1/20th second (there’re some blurred shots, but majority came out with acceptable sharpness). The Image Stabilizer gives an instant advantage for handheld macro photography. Canon claims a 2-stop advantage for the Hybrid IS in close-up photography – I think they’re underselling the system (read on).

I decided to push the experiment a bit further with a third scenario – handheld with support and Image Stabilizer. When I’m shooting macro, I often find support from surrounding trees and rocks when shooting handheld. So given that this new lens offer IS technology, how slow can the shutter speed be when I can shoot with support. The following images are shot handheld with the IS turned on, and my hands are resting on the tripod. I managed to achieve sharp images at speeds as low as 1 second, which is incredible!

Focus shift
With today’s DSLR, photographers tend to pixel peep at their images at 100% magnification in Photoshop, so any fault of the lens is immediately obvious. And one of the most dreaded phenomenon must be focus shift – where the lens is not actually focused on the subject you want to focus on. During exposure, the focus shifts slightly in front or behind the subject. So in certain images where focus is critical, focus shift  can actually cause an otherwise brilliant photo to be unusable.

Fortunately, the Canon EF 100mm L IS Macro does not exhibit any focus shift at all. Shooting wide-open and focusing on the extremely narrow focus plane, the EF 100mm L IS Macro captured all the details of the backlit grass perfectly.

When I first saw the huge lens hood that was supplied with the lens, I was thinking that this lens must be really prone to flare! Looking at the test results, the lens actually performs much better than I initially thought. In typical shooting conditions, it is not easy to detect flare with the EF 100mm L IS Macro. I shot through the leaves to induce flare on purpose, and the flare is well controlled within the image. Overall contrast remains high outside the hot spots, and the spillover happens only after f/22 or so. Even when wide-open where you’d expect the flare to deliver low-contrast results, the lens performs admirably. When shooting with the supplied lens hood, one would almost have to try very hard just to induce flare by finding situations like this!

Now that we got the academic testing stuff out of the way (gawd... I hate testing!), here're some of the images I shot with the Canon EF 100mm IS USM L macro lens...

So it is really sharp?
I think so. See for yourself the 100% close-up of the image as indicated by the white boxed area.

When I shoot with the EF 100mm L IS Macro, I’m reminded of sports such as tennis, golf or Formula One where advances in engineering make previously impossible feats possible. With the latest rackets, clubs and cars, you can drive harder, faster and more accurately than before. Likewise with the new EF 100mm L IS Macro, the cutting edge technology makes it so much easier to achieve sharper images handheld. Your success rate of good images improves dramatically, and you can shoot in scenarios where setting up a tripod may not be an option because position of tripod may not yield the best angle.

But for all the cutting edge technology, the EF 100mm L IS Macro is not the magic bullet for great macro shots. You’d still have to observe the techniques of proper handholding, and the shallow depth of field in macro photography makes it difficult to get a sharp image if you sway back and forth (that is something the Hybrid IS cannot resolve for you). And when fatigue sets in after a long day of photography, you might find a tripod may still work better. So if you own those expensive carbon fibre tripods, your investment is still safe!

But there’s no denying that your images will always be better with Image Stabilizer function, and that alone makes the premium of the EF 100mm L IS Macro over the standard macro lens worth the price. Couple the Image Stabilizer with the incredibly sharp optics of the new lens, the EF 100mm L IS Macro is a no-brainer for anyone who can afford the price premium (or who uses the lens extensively or professionally). The new Canon EF 100mm L IS Macro certainly requires discipline and hard work to bring out the absolute best in its lens quality, and it looks like this lens is destined to join the ranks of legendary EF lenses.


lucid said...

On the swaying in-and-out problem, you may find that the servo ai foucsing mode on the 7d with the expanded af point setting helps here. The servo apparently oversamples the distance when at macro fociusing distances, and can keep up with your swaying. It may be that other Canon bodies will do this also.

james said...

It is too light you can bring it anywhere easily. I think may be around 16 oz. It's a very nice product.

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