In most other areas of photography that I enjoy, I have read books or other tutorials on the subject but, for some reason, I avoided pretty much all information on macro photography and figured things out for myself. This means that I probably hit a lot more pitfalls than I should have and it also means that I may differ from the conventional wisdom but this stuff works for me so hopefully it will be helpful to others too. If any real expert reads this and wants to correct anything, please let me know!
I tend to think of “macro” as indicating “super close up” photography. Technically, though, “macro” refers to a photographic setup which is capable of reproducing something on the sensor at or larger than its original size or 1:1. In other words, if you are shooting pictures of a bug which is 1 inch long, your lens should project a focused image that is 1 inch long on the camera sensor.
This definition tends to get a bit blurred these days with many point-and-shoot cameras offering “macro mode” for close up photography even when this doesn’t actually give you life size images so some chose to suggest that a reproduction ratio of 1:2 (half life size) is still macro. You can take your pick – personally, I won’t argue with a great 1:2 picture that you want to call a “macro”.
The first problem you are likely to experience when trying to shoot macro is that you need to get very close to your subject to fill the frame with something as small as an insect. Typically, if you are using a normal lens, you will find that you are actually unable to focus on the subject when you are close enough to frame it the way you want. Your lens may only be able to focus on objects further away than, for example, 3 feet yet you need to be 6 inches from your target for the image size you want. How do we get round this problem?
If you are working with a point-and-shoot camera, you may find that it has a macro mode. This is often identified by an icon that looks like a tulip and this often sits next to an icon that looks like a mountain range. Choose the tulip and you will find you can focus a lot closer to the subject than normal. I’ve used a Nikon Coolpix 4600 and a Canon Powershot G9, both of which sport a macro mode which does a reasonably good job. If you are using a DSLR, however, or if you want to get real 1:1 magnification (which pretty much requires a DSLR), you have to consider other options.
The expensive solution is to buy a special macro lens. These lenses are intended to allow very close focus, typically down to an inch or two from the subject (depending upon the focal length) and solve this problem very nicely indeed.
Macro lenses come in various focal lengths. Nikon produce a rather fabulous 105mm VR Micro lens but my budget wasn’t up to that so I have a (still pretty excellent) Tamron 90mm Macro which I use quite frequently (as an aside, this is a great, fast, f2.8 portrait lens in addition to being excellent for macro work). The following images are example taken with the macro lens. Note that they are mostly of subjects that don’t move either quickly or often.
Extension tubes are hollow cylinders which fit between your lens and the camera body, moving the lens away from the film plane and allowing you to focus a lot closer than you would be able to without the tube in place. The downside of adding the extension is that you are now unable to focus to infinity but, for macro, that’s not a problem. I have a set of Kenko auto extension tubes that work beautifully and cost about $180. Auto tubes pass through the electronic signals between the camera and the lens so your metering, automatic aperture mechanism and autofocus will still work (though more on focus later).
Tubes are typically sold in a set of three offering different extensions (in my case, 12mm, 20mm and 36mm). They can also be stacked to provide other, longer combinations. The actual length of extension you need will vary depending upon how close your subject is and the focal length of the lens you are using. The longer the extension, the closer you can focus but you may find that if you add too much extension to a short lens, you won’t be able to focus at all. I don’t know the actual formula but by a process of trial and error, I’ve determined that 56mm of extension (the 20mm and 36mm tubes stacked) is perfect for shooting with my Nikon 70-300mm VR lens when I’m after dragonflies. With this combination, I can focus down to a foot or so away and fill the frame with the dragonfly very nicely. I’ll talk a bit more about using this combination later since there are a few quirks I’ve found when using a telephoto zoom and tubes.
If extension tubes are out of your price range, another easy-to-use option is a close-up filter. These come in various strengths (+1, +2 and +3 being common) and screw onto the front of an existing lens. They can be thought of as magnifying glasses that you attach to the lens and which allow you to focus a lot closer than you would normally be able to. Prices range from around $18 to $220 or so depending upon the size of the filter and the optical quality so there should be something available at a price that fits within most people’s budget. Although I have a +2 close up filter, I have never used it since I was given it after I had already bought tubes. Generally speaking, if I have a solution to a photographic problem that doesn’t involve sticking more glass between the sensor and the subject, I will use that solution first and the tubes work really well for me. If you don’t have tubes and you want to try macro photography, however, a close up filter is probably a great way to get started cheaply. Adorama lists a huge number of close up filters in their catalog.
The biggest problem I typically have to deal with when shooting macro is depth of field. When you shoot landscape or spend a lot of time looking through a wide-angle lens, this is not a problem but the closer you get to your subject, the shallower the region of sharp focus becomes. When you are a matter of a few inches away or even a couple of feet away with a longer lens, the depth of field drops off dramatically and you normally find that it is extremely difficult to get your whole subject in focus.
As you probably know, the solution to increasing the depth of field is to decrease your aperture (pick a larger f number) but this, of course, means that you have to decrease your shutter speed to compensate and you soon get into a situation where the shutter is too slow to give you an image without camera shake or movement in it. As a result, it’s a juggling act. Pick as small an aperture (as large an f number) as you can while still keeping your shutter speed in the safe region – no slower than 1/(focal length of your lens).
To illustrate the dramatic difference the aperture setting makes to the depth of field, consider the following two images. Both were shot with the Tamron 90mm f2.8 Macro lens and show a small section of a banknote. The camera was at about 45 degrees to the subject and the distance forom the front to the back is around 1 inch with the front of the lens around 3 or 4 inches from the subject. The first image was shot with the aperture set to f5 and a shutter speed of 0.1 seconds. As you can see, the depth of field is very shalow indeed – probably no more than a tenth of an inch.
An Indian banknote shot using a Tamron 90mm macro lens. Exposure – 0.1 seconds at f5
The second shot was taken without moving the camera. This time, the aperture was stopped down to f51 (yes, this lens allows you to use horribly small apertures when close to the subject) and, as you can see, the depth of field is dramatically improved with the majority of the image in sharp focus. The downside, here, of course, is that I had to leave the shutter open for 8 seconds to compensate for the very much smaller aperture).
An Indian banknote shot using a Tamron 90mm macro lens. Exposure – 8 seconds at f51
You have another variable that you can play with to help get around the shutter speed problem but you must take care since the effect will vary dramatically from camera to camera. Increasing your ISO sensitivity will allow you to either pick a smaller aperture or a faster shutter speed so, if I’m handholding and not using flash, I will typically bump the ISO up to 800 on my D90. On this camera (and on the D70 before it), this gives me results that look great at 12″x8″ and probably larger with some postprocessing. Do some experimenting with your camera to find out how it handles higher ISO settings since noise always increases with sensitivity and there will be a point where the noise is just too much for you.
Even after you come up with a suitable aperture/shutter speed/ISO combination to get the correct exposure, you are still likely to find that you can’t get the whole subject in focus. A couple of ideas that I find helpful are:
Don’t get the impression from this that you absolutely have to get everything in focus. Some really great macros use minimal depth of field to great advantage. While I’m not pushing these as examples of “really great macros”, here are a couple of my favourites where minimal depth of field actually helps the image (in my opinion). By having the majority of the image out of focus, the viewer is drawn to the elements which are sharp.
So you want to use a very small aperture to get good depth of field and a very fast shutter speed to freeze motion. Unfortunately, however, you are likely to find that these two things are mutually exclusive since you can’t dial the sun up and down at will. You can, however, add light to the scene using electronic flash. Special flash units for macro work are available but, being a cheapskate, I use my standard flash units (a couple of Nikon SB600s in my case) and these do a great job as long as the subject is reasonably stationary. Adding a flash to the mix, I can easily add enough light to shoot insects all the way down to f32, f45 or lower.
When using the 70-300mm + extension tubes, I normally cheat and just mount a single SB600 on the camera hotshoe. This lets me shoot dragonflies a couple of feet away at f22 which gives me adequate depth of field. The light is not particularly beautiful with the single direct flash but it works well enough especially when I can’t get access to the side of the target to set up light stands or tripods. If I do have all-round access or helpers willing to hold flashes, I will take the flash off the camera and either put it on a stand close to the dragonfly’s perch but to one side of my shooting position then fire it using the on-camera flash as a CLS commander (read Joe McNally’s excellent “Hot Shoe Diaries” for more information on how to do this). If I’m really keen, I will also set up a second light on the opposite side, dialed down a stop or two to help fill in the shadows a bit and reduce the harshness of the light. Another trick is to aim the second light towards the background to brighten it a bit if you don’t like the black that you will often get if you fire a thermonuclear burst from 3 inches at the foreground and expose for this.
At this point, you’ve decided what exposure you are going to use and whether you are adding more light to the scene or just going with what nature provided. The next step is actually to take the picture. In actual fact, the next step is to take a lot of pictures. Like it or not, it is most probably that the vast majority of your exposures will be thrown away, especially if you are working outside and there is any kind of breeze causing your subject to move. With focus so critical this close to the subject, the slightest movement of the subject is likely to take it outside your zone of focus and result in a blurred image. Take lots of images and you are a lot more likely to get one of them which is sharp where you want it.
Depending upon the optical setup you are using, you may find that you can’t rely on autofocus either. Given that many autofocus systems have a habit of hunting back and forward to find the focus, this may cause you problems as your target moves slightly and, as a result, you may find it easier to switch to manual focus even if your autofocus is capable of operating with whatever tubes or lenses you are using. In my case, I use manual focus 100% of the time when using the 70-300mm + tubes setup and about 80% of the time with the Tamron 90mm Macro lens. The only time I use autofocus with the Tamron is if I am shooting stationary subjects from a tripod or if I am holding an off camera flash and don’t have a hand free for the focus ring.
When using natural light, use manual focus and turn the focus ring until the subject is sharp at some point in its motion. I then rely upon a burst of 3 or 4 exposures in continuous mode and generally one will be in focus. Another trick is to focus then rock slightly back on your heels and shoot a burst as you rock ever so slightly forward again.
When using flash, the high speed burst approach is unlikely to work since your flash almost certainly won’t recharge as quickly as your camera can shoot consecutive pictures. In this case, I shoot single exposures and merely wait for the recharge between each one. It takes longer to get your super-crisp final image but it’s generally worth the wait.
For extreme close up work with the long lens and extension tubes, I’ve found another trick that works well for me. Focus initially with the focus ring on the lens with the zoom about half way through its range then use the zoom ring to fine tune the focus. Don’t ask me how this works since it sounds rather odd but at these distances, minor changes in the zoom setting don’t make a huge difference in the image size but do pull the subject into or out of focus. Generally lenses such as this have far larger, more positive feeling zoom rings and I find it easier to tweak the zoom ring slightly than muck with the smaller, less handy focus ring. I can imagine that many readers won’t believe me but I would encourage you to try it and see.
As a rule of thumb, I am delighted if I get one image that is sharp where I want it to be in ever 6 exposures when using flash (where the depth of field is likely to be a lot deeper) or in every 20 shots if handholding and using available light at a wider aperture.
Go out and have a play – macro photography is great fun and doesn’t have to be particularly difficult. Just remember that to get a really great photo, you have to take a whole lot of really bad ones too.