Thom's Quick & Dirty Guide to Macro


99% of what you need to know in 1% of the space.

Original: 5/10/2010

  • Learn what 1:1 and other ratios mean. Specifications for macro lenses or settings often give the magnification ratio with a 1 followed by a number, such as 1:2 or 1:1. For images up to to "life size," that second number is the important one. 1:1 is life size, meaning that an object 10mm in real life will be recorded as 10mm at the sensor. 1:2 is half size, meaning that an object 10mm in real life will be recorded in 5mm at the sensor.
    • It doesn't really matter if you're using DX or FX. The magnification ratio doesn't change for different capture sizes, though a 1:1 lens recording a 30mm object will obviously be able to fit that onto an FX sensor (36mm wide) and won't on a DX sensor (24mm wide).
    • Ratios with the 1 second, such as 2:1, mean greater than life size. In the case of 2:1 an object that is 10mm in actual size will be recorded in 20mm on the sensor.
    • True macro lenses tend to be 1:1, or at least 1:2. There is a difference between a "macro lens" (one designed specifically for close-up use) and "a lens with a macro setting" (a lens that has closer than "normal" focusing). I've seen the latter marked as "macro" as low as 1:5 (one-fifth life size). I've never seen the former with less than 1:2 (one-half life size).
    • Lately Nikon has been using a more understandable Maximum Reproduction Ratio number, such as 0.25x. Divide that into 1 and you get 1:4, for instance. Likewise, you can get this number from the older style by dividing the left number by the right one (e.g. 1:2 = 0.5x). In this system, 1x is life size, 0.5x is half size, and 2x is double size.
    • Don't know the ratio for your lens? Measure it. At the closest focus you can obtain, shoot a ruler marked in millimeters. For FX bodies, divide the number of millimeters you see across the frame by 36, for DX bodies divide by 24. Thus, if you see 48mm on a DX body, your lens goes to 1:2 (or 0.5x).
  • Be aware of "working distance". Working distance is defined as the distance from the front of the lens to the subject. A broad generalization is that the more focal length in your macro lens, the larger the working distance. Thus, a 35mm macro lens will get 1:1 at very, very close distances to the subject, while a 200mm macro will be a much greater distance from the subject. Nikon has gotten coy lately and is no longer putting working distance on their primary lens product pages. Here they are for 1:1:
      • 60mm: <2"
      • 105mm: ~6"
      • 200mm: ~10"
    • Spooking. If your subject is an insect or animal, the closer you get, the more likely that you spook it. Dedicated macro shooters deal with this by chilling their subjects or shooting them when they're still cold from the night air.
    • Lighting. The closer you are to the subject, the more difficult it is to light it. Nikon's SB-R200 macro flash units are a bit too harsh when used with the 60mm lens at closest focus, in my opinion. Plus you barely have an ability to sneak the light into the area between the lens and subject.
    • Blocking. Related to lighting is blocking: you're so close to the subject that you block light from getting to it. Short working distances mean more blocking, long working distances mean almost no blocking.
    • Focus. If you're not on a sturdy tripod with the camera on focusing rails (e.g. handholding), holding the focus point perfectly can get tougher the closer you are to the subject. AF-S lenses will often hunt frantically if you try to handhold and can't keep absolutely steady (hint: autofocus is not how you get the best macro shots).
  • Apertures appear to do strange things (but actually don't). Most modern macro lenses use both focus extension and focal length breathing to achieve their maximum magnification. This has implications on maximum aperture. A lens marked f/2.8 may actually be f/4.5 or even f/5 at maximum extension, and it may not be the full focal length marked on the barrel. This is normal. But this can mean the difference between using ambient light or having to supply extra light.
    • The camera corrects for this. If you're using a modern macro lens on a modern Nikon body, the exposure system figures out that the effective maximum aperture is changing and adjusts.
    • But manual exposure enthusiasts need to adjust. If you're calculating exposure manually--for instance, supplying a specific amount of light via manual flash--you'll have to take note of the aperture change. No worries, the camera should be telling you what it is.
  • Focus is a pain. Two points: achieving the right focus is tough if you or your subject is moving, and focus even at small aperture openings will still have a very narrow depth of field.
    • Focusing rails are handy. Shooting from a tripod with a good head plus a set of focusing rails allows you to be very precise with your focus. As long as your subject isn't moving! Again, dedicated macro shooters tend to chill live subjects to keep them from moving, or shoot them at times when they aren't likely to move. With plants, the use of a Plamp or McClamp (hint: B&H sells both) can help keep plants from swaying in the breeze, but you may have to build a wind break, too. (hint: take a look at the tri-fold student exhibit poster boards that places like Staples sell; not only can they serve as a inexpensive, portable wind break, but they act as reflectors for the light.)
    • Focus stacking is a post processing solution. If you've got a non-moving camera setup and a non-moving subject, bracket the focus via a series of shots, then use a post processing focus stacker to effectively increase depth of field.
    • To Diffraction and Beyond! You'll usually find yourself stopping your lens way down to try to achieve some semblance of depth of field. This is likely to put you above what I call the diffraction limited aperture for your camera. Don't worry about that. You're better off with "focused with diffraction" than "out of focus and no diffraction."
  • Inexpensive alternatives exist. If you don't want to spring for a dedicated macro lens or are averse to carrying yet another lens, you can temporarily modify one of your existing lenses using either extension tubes or closeup lenses (note that these both work better and are more useful on telephoto lenses than wide). When you have either of these things mounted on your lens you will lose infinity focus and you'll have to spend some time adjusting to how they impact focus overall (while the change in focus range is predictable, most people seem to have a difficult time adjusting their thinking by looking at adjustment tables--they need to experience it through the lens a few times before they figure it out).
    • Extension tubes. Basically what the name implies: a hollow tube that fits between the camera and lens. This is similar to allowing the lens to focus further forward (extend, thus the name). I'll cut to the chase: just get the three-piece Kenko set (12, 20, 36), or just the smallest one (12mm). While no longer dirt cheap, the Kenkos are the only tubes that do a decent job of bringing the lens data to the camera. Curiously, Nikon has never made an autofocus extension tube, though they made a lot of AI ones in the manual focus days. The good thing about tubes is that they don't really have any impact on image quality. Start with a good lens and add a tube, and you still have a good lens. Vignetting can increase though.
    • Close-Up lenses. These (sometimes called diopters) are like filters that screw on to the front of the lens, and much like your eye-glasses or contacts, they correct focus to a different distance. Avoid the single-element close up lenses, as they impart too many image quality penalties to be fully useful. Nikon used to make 52mm and 62mm multi-element sets (e.g. 5T and 6T), and Canon still makes the multi-element 500D. These Nikon and Canon close-up lenses are the "gold standard," in my opinion. The 500D on a 70-200mm makes for a very reasonable "macro lens." However, because you're adding lens elements, there can be image degradation, which is why you want one of the better sets, not a cheapo single-element diopter.
    • Hint: zoom all the way in and get used to the change at one focal length before trying to master zooming with a tube or close-up lens. Some zooms designs focal length breath or do other tricks like moving the "optical center" outside the lens, and these are notoriously difficult to master with a tube of close-up lens. Unfortunately, the popular 18-200mm is one of those. It's better to use your telephoto zoom or a telephoto prime for macro work.
    • Infinity is infinetly unreachable. Once you put a tube or close-up lens on, you lose infinity focus (and possibly much closer than infinity!). Basically, the whole focus range of the lens moves closer to you.

Thom's Quick Recommendations (all your really need to know):

  1. Avoid short macro lenses. You need more working distance than the 60mm provides, especially for maximum magnification.
  2. Let the camera do the exposure math. Use one of the automated exposure modes (avoid manual exposure mode).
  3. Support needs to be perfect. No skimping on tripod legs or head. You need a solid setup to do macro right. And that usually includes adding a focusing rail for precision manual focus.
  4. Yes, manual focus. You don't need a fancy AF-S or HSM macro lens for macro (you might want that focus ability if you use the lens regularly for normal photography, though). Indeed, the older manual focus Micro-Nikkors work perfectly fine and can be picked up fairly cheaply, a good choice for D300, D700, and D3 series users.
  5. Lighting is the toughest issue. Have pocket reflectors and diffusers handy and learn how to use them. Nikon's R1C1 (SU-800 with dual SB-R200's) is adequate if you've got enough working distance, but for very close lighting I find it a bit harsh. Experiment with unconventional lighting sources (e.g. flashlight through diffuser, any light through milky white plastic to diffuse it, low-cost manual ring flashes, etc.).
  6. Keep an extension tube or Close Up lens handy. They pack small, so can be carried anywhere. They can solve close focusing problems and impromptu macro needs without your having to carry a macro lens all the time.

Thom's Recommended Macro Lenses (in preference order):

  • Micro-Nikkor 70-180mm (discontinued). Only goes to 1:1.32 without a 6T, but very versatile and sharp lens. Not AF-S. Not VR. Neither are big deal for dedicated macro work.
  • Micro-Nikkor 105mm. Goes to 1:1, handles well, has AF-S and VR for handheld work outside macro range. Sharp (though a smidgen softer than its non-VR predecessor). Decent working distance, and R1C1 works okay at that distance.
  • Tamron 90mm. The bargain macro. As sharp as any short telephoto I've tested, and gets to 1:1 for macro work with a decent working distance.
  • Micro-Nikkor 200mm. This lens needs updating (add AF-S and VR ala 105mm for general use). The workhorse of many outdoor nature photographers primarily because it's sharp and has the longest working distance of any of the Nikkors.

Macro Lenses Thom doesn't recommend:

  • Micro-Nikkor 60mm. Working distance is too short for all but perhaps copy stand work.
 

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