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Canon EF 100mm f/2.8 Macro USM by Markus Ehrenfried
Almost all of the macro photos you will find on these webpages are taken with the Canon EF 100mm f/2.8 Macro USM lens. Search for reviews on the web: you will hardly find anything negative said about this macro lens, and I can tell you: there is a reason for that. This lens is capable of delivering incredible sharp pictures, both used as macro lens at very close distances and at infinity used as a very good 100mm telephoto lens. This is achieved by a lens design incorporating so-called floating elements. A floating element is a lens or a group of lenses which changes its position within the optical system depending on the focusing distance. Normaly, if you optimize a lens for being sharp and well corrected at infinity, it's performance will degrade the closer the focusing distance becomes. To optimize it for that distance you would have to change the distance between the lenses inside the optical system slightly. And this is exactly what a 'floating element' does automatically, therefore keeping the optical quality of the system on a very high level for each distance you choose to focus on.
The Canon 100mm macro lens allows magnifications up to the scale 1:1 with approx. 15cm free working distance (between the front lens element and the object) at its closest focusing distance. A scale of 1:1 means that the object has the same size on the film than in reality. You might think this doesn't sound all too impressive. But keep in mind that there is a reason why 24x36mm is called 'small format'. A scale of 1:1 means that e.g. an insect with a size of 1cm in real live will be projected on your film with the same size of 1cm. On the prints you get back from the lab (enlarging 24x36mm to e.g. 10x15cm) the picture of this insect will be MUCH larger than the real life size of the insect! A butterfly like the one in the picture below is in reality so large that you will already have trouble to get it fully into the 24x36mm frame at 1:1 magnification.
The lens described here has an USM which means Ultra Sonic Motor. This is a technology developed by Canon and you can find a description how it works on their website. The advantage of this type of autofocus motor is, that it is much faster than the older DC motors and very very silent. The USM version of the Canon 100mm macro lens is the successor of an older version which used a normal DC motor. Many shops will still have the old non-USM version on stock (as there are not so many people who buy macro lenses), although the USM version is already available for some years. The optical performance of those two lenses is probably comparable. Also the older version had outstanding optical qualities. You may ask if one really needs fast autofocus in macro photography. Depth of field is so small at close focussing distances that most macro photographers set the lens to the approximate distance and then slightly move the camera back and forth until the area of interest comes into focus. This is much more accurate than turning the focussing ring. I actually did this for quite some time, but this requires constant attention and my eyes became tired soon and I had difficulties to decide whether the object was really perfectly sharp or not. Then I tried another technique and found that it worked remarkably well, but only due to the extremely fast autofocus: I preselect only one of the seven AF sensors my Canon EOS offers and let the lens focus on that. Then I decide quickly, if indeed the area I wanted to have sharp is in focus and either release the shutter or just autofocus again. Working like this is less tiresome and I have the impression that I get now more sharp photos than ever before with the manual focus technique. But there is another improvement between the newer and the older version of this lens apart from the faster AF motor: it is internally focussing. This means that there are absolutely no moving parts on the exterior of the lens. This is an incredible advantage. The older, non-USM macro lens would constantly change its length while focussing, and not only a bit: during 'hunting' for correct focus it would between the closest focusing distance and infinity easily change it's outer dimensions by a factor of two! This alone made it impossible to use it with AF for macro photography, apart of being of course much too slow. A second issue is, that a lens which changes its length during this process sucks in air (and therefore inevitably dust), which again really sucks. This is no longer an issue with the new internal focussing lens design. Also polarization filters are much easier to use as the front element no longer rotates during focussing. The bottom line is: this is the lens you want to buy, not the older version. And Canon didn't even raise the price! They brought the USM version for the same list price on the market than the older version, which it replaced, had at this time. There are shops which try to sell you the older version for the price of the new one, so be cautious. I read one review somewhere and somebody explained why he prefered the older version. At the new lens, the front element is really in the front which makes it much more prone to stray light and flare. This can reduce the contrast of your pictures. At the older version, the front lens element was deeply recessed inside the barrel. Therefore one should probably use a lens hood with the new USM version of the lens. I cannot comment on that. I don't own the lens hood (it doesn't come with the lens) and Canon asks a ridiciulously high price for this cheap piece of plastic. But on the other hand, I up to now never had the impression that flare is a serious problem with this lens. I found the contrast to be quite pleasing. Did I already mention that this lens is incredibly sharp?
On the left side of the lens barrel (viewed from above) there are two little switches. One is for AF vs. MF. The other one can limit the focussing range. There are two settings: you can either use the full range from 0.31m to infinity or a restricted range from 0.48m to infinity. The second setting will speed up focussing significantly if you use the lens as a 100mm telephoto lens instead of as a 100mm macro lens as it will not hunt for focus in the very close range between 0.31m and 0.48m.
Canon offers four lenses for macro photography:
So, the MP-E 65mm lens is not really an option, which leaves the 50mm, 100mm and 180mm lens. I decided that I find the 100mm lens most suitable for the kind of macro photography I enjoy. These are my reasons:
The bottom line is: I personally find the 100mm focal length extremely convenient for macro photography. It is also a superb telephoto lens (-- I compared it on another page to the Zeiss 90mm rangefinder lens). And apart from being heavy (which is not really a disadvantage as it is built very solid!) and expensive, there is absolutely nothing I can criticize about the Canon 100mm USM macro lens: it is incredible sharp, produces very nice contrast and colour rendition, focuses extremely fast and it renders the out-of-focus areas in a beautiful, smooth way. In my opinion it is indeed the perfect lens for macro photography!
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References [1] Michael Reichmanns review on his Luminous Landscape website | ||
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