Introducing macro

Where so far this guide has focussed on some of the rather technical aspects of photography, we're now moving on to a specific technique: macro. Macro photography is the rather confusingly named practice of taking pictures of really small things. Popular subjects are insects and flowers, but anything that is either really small or has a lot of small detail will do. The way this is achieved is by getting very close to the subject and the defining aspect of macro photography is therefor very short focussing distances.

Magnification

The magnification of an optical system is how large the image is compared to the original subject. A 1:2 (or 0.5) magnification means that a 1cm subject is projected as a 0.5cm image. Note that this is the physical image inside your camera: this will later be magnified further by viewing it on a screen or printing it out. In digital photography we use lenses which project onto a sensor. The size fo the four thirds sensor is 17.3mm by 13mm. If we use a setup which grants a 1:2 magnification that means that the smallest subject area that we can fill the entire sensor with is 34.6mm by 26mm (magnification is linear in each dimension). If we instead used a setup with 1:1 magnification the smallest subject would be 17.3mm by 13mm: the size of our sensor.

In photography, magnification depends on actual focal length and focussing distance. If you look at our lens list, you'll see that the maximum magnification is listed for each lens. It is important to note that this maximum magnification is only achieved at the closest focussing distance and largest focal lengths that those lenses are capable of. For example the 0.52x macro of the ZD50mm lens is only achieved at 24cm. You'll also note that this value seems to be largest for the lenses specifically designated as "macro", this is because these lenses are specifically designed to focus closer and to supress focus breathing (discussed later).

Magnification and sensor size

Olympus will sometimes advertise the ZD50mm lens as a 1:1 'equivalent' macro lens, even though it's actually a 1:2. The reason for this is that four thirds sensors are about half the size in each direction as a 35mm film slide. Therefore an image projected on them only needs to be half as large to fill the entire sensor. If you look only at the final image (on a monitor or a print) a 1:2 macro on four thirds acts like a 1:1 macro on a 35mm ("full frame") camera. While this is fine and dandy for marketting or for people coming from film photography, it gets rather confusing when we start using lenses from different makes or old film lenses. Much easier to just use the real values and call a 1:2 macro a 1:2.

Focus breathing

I said before that magnification depended on focal length and focus distance, but looking over the lens list we find some seeming exceptions to this rule. For example the ZD50mm has a minimum focus distance of 24cm and a magnification of 0.52x while the ZD14-54 has a minimum focus distance of 22cm and a magnification of only 0.26x. The reason for this is that for most lenses the focal length drops when you focus closely. So while the ZD14-54II will be 54mm when zoomed out and focussing on a distant subject, it will be a lot less when focussed closer. This effect is called "focus breathing" and tends to be more severe for zoom lenses than primes. Even amongst similar lenses there can be a big difference however, as we can see when we compare the two 14-50mm panaleica lenses (same min. focus distance but 0.16x and 0.21x max magnification).

Macro lenses were designed specifically to minimize this effect.

Macro gear

Not all lenses are suited for macro right out of the box, in fact most aren't. To make things a bit complicated, there's many options for macro. I'll go over the most common ones, going from cheap to expensive.

Diopter adjustment filters

More commonly called "close up filters", these 'filters' are actually small lenses that you use like a filter. They allow you to focus closer and come in many strengths, starting at +1 and generally going to +5 and +10. They can be combined as well, a +1 and a +2 are the same as one +3. A set of them (usually +1, +2 and +5) can be had for as little as 20€ or as much as 80€, where the more expensive ones have the better quality.

While cheap, the quality of this solution isn't too great, with chromatic abberations and sharpness loss quickly becoming a problem, as you can see from the crop on the right. Still, if you're on a budget, it's a good way to get into macro photography and I would recommend people to start with these filters before they invest in any of the more expensive solutions.

Third party extension tube

Four thirds compatible extension tubes can be found quite cheaply on ebay. Extension tubes slot in between your lens and the camera body, which decreases the focus distance. It also makes it impossible to focus on infinity. The quality of this is generally better than with close-up filters, especially when combined witha dedicated macro lens.

There's one big caveat to these third party adaptors tho: they do not communicate with the body or the lens. Because many four thirds lenses uses a focus-by-wire mechanism, this means you cannot adjust the focus at all with these lenses and unless you use some fancy tricks are stuck on infinite focus: the exact opposite of what you want. Furthermore, you cannot change the apperture, so you're stuck with whatever is the default for the lens (which will often be wide open, again the opposite of what you want). For this reason I would discourage you strongly from getting these adaptors for use with four thirds lenses.

Close-up lens/filter

I'm making a rather arbitrary division between the filter/lenses above and the more expensive versions like the Canon 250D, Canon 500D, raynox DCR250 etc. While they both do the same thing - screw them in front of your lens to reduce the focus distance - these more expensive ones provide much better quality. However, expect to pay between 70 and 200€ for them, depending on the size.

Legacy macro lens

Due to technical reasons, four thirds is a good format to use old film-era lenses on. Many of these lenses can now be bought for relatively little money and there's quite a few good macro ones to be found. Keep in mind, however that you'll also need an apropriate adapter, which can be found on ebay.

The disadvantage of using legacy lenses is that you lose autofocus ability, however with macro photography you'll find that often you'll use manual focus anyway (keep the lens set to minimum focus and move the camera to focus).

Legacy lenses can be coupled with legacy extension tubes to further increase their macro pottential (and because these lenses have a mechanical focus mechanism and aperture ring they do not suffer the previously mentioned issues with third party extenders).

Because for macro use you don't care about focussing to infinity anyway, you can use some lenses that normally don't work on four thirds like Canon FD and Minolta MD. The mount adaptor then doubles as an extension tube.

EX-25 Extension tube

The Zuiko Digital EX-25 is a 25mm extension tube for the four thirds system. It works exactly the same as the third party extension tubes mentioned above with one important difference: this one does communicate with both the body as the lenses. As a result, you retain focus and aperture control on most lenses. As with other extension tubes, using the EX-25 makes it possible to focus considerably closer while losing infinity focus.

Note that some lenses can not be used with the EX-25. The reason for this is that it reduces the focussing distance so close that you'd have to place the subject inside the lens for it to be in focus. Generally you need a lens witha  focal length of at least 45mm to be able to use it.

The EX-25 was designed primarily for the ZD50mm. Using the two together gets you a true 1:1 macro lens. However, it has been used with many other lenses and is particularly popular for the ZD50-200 and the ZD70-300. I've personally tried it with the 40-150 with mixed results (it works, but not over the entire zoom range and autofocus can be tricky) and with the sigma 135-400 (an amusing experiment).

ZD35mm macro

The cheapest of the four thirds macro lenses, the ZD35mm has its bigger brother (the ZD50mm) beaten in that it is a true 1:1 macro lens. This means that without the EX-25, it gives a greater magnification. The downside is that it does so at such short focussing distances that the front element of your lens almost touches the subject.

ZD70-300mm

While not designated a macro lens by Olympus, the Zuiko Digital 70-300mm standard grade long tele zoom nonetheless has an impressive magnification of 1:2. This is roughly the same as the ZD50 macro lens. At 300mm, this lens also gives the greatest working distance which is good for insect shots (flowers aren't as skittish). As with the others, this lens can be combined with extension tubes and diopter lenses to increae the maginifcation, but because it is not a dedicated macro lens this will degrade the quality more than with the other lenses here.

TC-14 and TC-20 Teleconvertors

The teleconvertors increase the focal length but leave focussing distance the same. While not the most effective way to achieve macro, this can be used to increase the magnification on an existing macro lens.

Sigma 105mm macro

A much-loved lens by those who have used it, the sigma 105mm is a 1:1 macro lens that allows for a larger subject distance than both of the Olympus offers. While it's less versatile a lens than the ZD50, as a dedicated macro lens it's hard to beat, especially at this price. Just be careful and test to make sure you havea  good sample, as sigma lenses are occasionally a bit dodgy on the focus.

ZD 50mm macro

This is probably the most widespread of the four thirds macro lenses. While it's only a 1:2 macro (1:1 with the extender), the ZD50 is heralded as one of the sharpest lenses there are for four thirds (and in fact one of the sharpest lenses for any system) and with a max apperture of f/2.0 doubles up as a great portrait or lowlight lens. Unlike the other macro lenses it's also weather proof. Still, if all you're going to use it for is macro, one of the sigmas may suit you better.

Sigma 150mm macro

The longest of the macro lenses and thus the one with the largest working distance (which helps a lot when taking pictures of insects). This is another 1:1 macro lens which doubles as a decently fast tele prime. As with the sigma 105mm, make sure you get a good sample.

More exotic options

Other options exist, but tehse are generally not recommended for beginners:

• Macro bellows are basically variable-size extension tubes.
• Lens reversal puts a lens upside down on your camera, creating a high magnification macro lens (best used with an old manual lens, say a 50mm f/1.8)
• Macro coupling rings combine a normal lens witha  reversed one, again giving a high magnification

Macro considerations

Depth of field

To increase magnification, we strive to reduce working distance and increase focal length. If you think back to the depth of field page of this guide, you'll remember that both of these decrease Depth of Field. Macro photography by its very nature has to struggle against very shallow depth of field. When using the ZD50mm with the EX-25, for instance, the depth of field wide open is a fraction of a millimeter.

The way the depth of field calculation works, focal length and focus distance changes will balance eachother out if they both change in the same direction. If you double both focal length and focus distance, the depth of field will remain the same. This is important in macro, because magnification has the exact same relationship to those two parameters. Thus depth of field is affected only by magnification and aperture: the ZD35mm will have the same depth of field as the Sigma 150mm when both are at their respective minimum focus distances, since both are 1:1 macro lenses.

This means that we can only use aperture to increase depth of field. When doing so, keep in mind that on four thirds lenses you will start seeing some sharpness degradation starting at f/11.

Working distance

It's been mentioned often enough by now: macro relies on very short focussing distances to increase magnification. The reason I'm bringing it up again is to make sure you realise just how short these are. In fact the working distance is a lot shorter than you might think from reading specs. The distances given on the lens page are minimum focussing distances, but the distance between teh subject and the front of the lens is a lot shorter than this. For example for the ZD50mm this distance is less than ten centimeters. When taking pictures of living subjects, like insects, this means you may scare them away. Again: the greater the focal length, the greater the working distance.

Lighting

Because of the small apertures needed to gain depth of field, you will need a lot of light to take your picture. At the same time the short working distances mean that more often than not you're blocking the light with your camera or lens. Both these combine to make lighting very tricky and often natural light will simply be insufficient. If you're really serious about macro photography, you may want to invest in a ring flash or a macro twin flash setup. Otherwise: up the iso or use a tripod. Personally I tend to use iso 400 to 800 for macro pictures.

Motion blur and shake

Since you're taking pictures fo very small things, camera shake is a lot more noticeable. Every little movement you make will be magnified along with your subject. This is very important because again, you'll be working in low light.

Technique

So far the technical background. I'll be a lot briefer about actual technique since I believe the main issue here is to practice a lot. Therefore, I will limit myself to some general guidelines:

• Use aperture priority and select a small aperture (f/8 and above).
• Use picture review to see if you should increase aperture, but be aware that it's actually quite hard to see here. If you can, check on a computer monitor.
• Be aware of motion blur. Don't let your shutter speed drop too much. Increase ISO or use a tripod with mirror lock up.
• Use manual focus and move the camera slowly to focus
• Be aware of your surroundings: try to avoid blocking sunlight with your camera or lens. Don't bother with a lens hood.
• Have fun