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| Macro lenses | |
Canon 100 mm f2.8 USM This small, sharp, highly functional lens works superbly for many macro subjects and is also excellent at more 'normal' shooting distances. Compared to a regular 90-105 mm lens, it's a little bulky, especially with the optional (but sometimes useful) tripod mount attached. Nevertheless it is fairly easy to maneuver and has a small enough filter size to attach a ring flash for even lighting. If you don't use the (optional) large lenshood, the on-camera flash of many DSLRs provides good lighting up to 1:1 reproduction. It's
an excellent lens optically,
gets to a 1:1 reproduction ratio without extra extension, and has very good build quality. It's light for a macro lens, and although skeptics wonder how autofocus can possibly be useful for macro work, at times it's very helpful: just try following a walking beetle or bee and maintaining focus manually and you'll come to appreciate macro AF. Another virtue is that it doesn't cost an arm and a leg. Highly recommended for routine macro work, although it's a little short for flighty subjects like lizards and many insects. I've used it with both film and digital Canon bodies and (occasionally) the 1.4X converter. The Canon 1.4X or 2X have optics that project in front of the lensmount, so to use them with the 100 mm macro you have to insert an extension tube between lens and converter; a 12 mm tube works fine, although autofocus may be lost. A stabilized and weather-sealed 'L' version of this lens was introduced some years ago and is reported to have similar optical quality to the older version. More recently, Canon released an RF-mount version for mirrorless cameras. 
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Tamron 180 mm f3.5 Having a fondness for images of small wary subjects, I considered getting a 'long' macro lens for some time and finally purchased the Tamron 180. It is smaller, lighter, and much less expensive than the Canon 180; a few reviews suggest it is a bit sharper than the Canon at both macro and 'regular' distances.
Two negative aspects of the Tamron are worth noting. First, it's not a USM lens, which means you have to declutch the autofocus motor to manually focus. As such mechanisms go, the Tamron system is simple: you push and pull on the focus ring to click between manual and autofocus positions -- but it's a bit stiff and the operation is a bit frustrating for someone used to the no-fuss full-time manual focus of a Canon USM lens. The second annoying 'feature' is the 'filter effect control' that lets you rotate an attached filter even with the (large) lenshood attached. I've no idea if this works for filters, but it's aggravating to attach a ringflash or other front-mounted macro flash and have it spin around the lens axis. A lock button or switch would fix this problem neatly (I fixed it with some electrical tape). A minor glitch: the tripod mount is a bit longer than necessary, adding needless bulk. Those warts aside, Tamron is an excellent lens optically, gets to 1:1 reproduction without extra extension, and seems quite well made. It's light for a long macro lens, and although the MF/AF transition is clumsy compared to a USM lens, manual focus is smooth and autofocus -- while slow and noisy -- is fairly accurate. Note: no longer in production but sometimes available used. |
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Sigma 150 mm f2.8 OS This is a fast, heavy, and stabilized autofocusing macro lens. Reviews, and my own experience, indicate that it is optically excellent, as are most macro lenses. It gets to 1:1 reproduction without additional extension, and -- unlike the Canon 100 mm and Sigma 180 -- can directly accept the Canon 1.4X and 2X extenders. It functions very well with the 1.4X, with fine image quality; as one might expect, things are a little dicy with the 2X in terms of both autofocus and optical results. I've also combined it with extension tubes to get greater magnifications, such as with the small jumping spiders at right.
As is hopefully indicated by its substantial weight, the lens seems very solidly built and handles well (aside from its mass). Manual focus is smooth and requires no messing with switches -- just turn the focus ring, as with Canon USM lenses. The easily removeable tripod mount is a bit less necessary with this lens than with other macros due to the 'OS' stabilization system, but unfortunately stabilization works less well at macro distances than at long range. Interestingly, the lens is supplied with two hoods, one for full-frame cameras and a slightly smaller one for APS format DSLRs (I just use the full-frame one). Note: no longer in production but sometimes available used. 
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Canon MP-E 65 (65 mm f2.8) This is a very specialized and challenging lens. It does not work at all for 'normal' photography -- it's minimum magnification is 1:1 -- but it is probably the easiest option for most photography of small objects out to 5X magnification. At 5X, a subject a few mm long will fill the frame. The MPE-65 looks fairly compact in the 1:1 setting, but it hugely extends as you go from 1:1 to 5:1. On a DSLR, increasing magnification also elicits a shift from an OK viewfinder image to a very dim one (and it's manual focus). Fortunately, viewfinder dimness is less of an issue with mirrorless cameras. Depth of field is miniscule and due to diffraction effects at small apertures, you can't do much about it (because of the long extension to reach 5:1, the maximum aperture drops to f16 or so). Stopping down to gain some depth of field will unavoidably result in loss of sharpness due to diffraction. One solution is to 'stack' images: use a focus rail or automated focus shifter to produce a series of images, each at a slightly different plane of focus, and then combine them using specialized software (obviously this likely won't work very well for subjects that move). Yet another issue is that the working distance between the front of the lens and the subject is roughly an inch (2.5 cm) at high magnifications, making it almost vital to use a dedicated macro-flash unit. In sum: a great lens for its intended purpose, but definitely not for everyone. 
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