Choosing a macro lens

When you’ve been bitten by the photography bug, after the usual focal lengths have been covered by a zoom or two, a macro lens is often the first optic that will attract serious interest. It’s easy to see why, as a macro model gives you an entirely different view of the world, and offers the opportunity to capture subjects that are barely visible to the unaided eye.

But to be a true macro lens, there’s a certain quality the lens must possess, and that’s down to how close it can focus. The term ‘macro’ is laser-etched on the barrels of all kinds of different lenses, mainly because the loose world of marketing isn’t as particular as the precise world of science. You’ll see ‘macro’ on a lot of telephoto zooms and even on some wide-angles. But if the lens doesn’t focus at 1:1 – where the object is the same size in real life as it would be if you placed it directly on the camera’s sensor – then it’s not a genuine macro lens. A reproduction ration of 1:1 (also known as 1x magnification or ‘life-size’), is the true starting point for macro, and anything that falls short of this mark is merely ‘close-up’.

So if your 70-300mm zoom says ‘macro’ somewhere on the barrel, it doesn’t really mean it – it just means it can take close-ups when you’re at the long end! The lens below, for example, states it offers a macro function, but it’s actually a 1:2 lens, offering shots at half life-size. This is still great, but it doesn’t offer the 1:1 capability of a dedicated macro lens – it’s just defining the term in a looser way.

All that claims macro isn't really macro. It might be fine for some close-up shooting but you won't be able to photograph your subject at life-size.

With the terminology out the way, which macro lens you choose is restricted by the lens mount your camera offers. That’s no different to any other lens though, so no worries there! When you’re researching your options on websites, restricting your search to ‘Micro 4/3rds’, ‘Canon fit’ or ‘Nikon fit’ will narrow things down to practical examples that will actually go on your camera, but there’s still a healthy variety of choices, thanks to quality offerings of third-party lens makers like Tamron, Sigma, and the like.

Although a few genuine macro-zooms exist, in the vast majority of cases, macro optics are prime lenses, so possess a fixed focal length with no ability to change the composition without moving the camera. This takes a bit of getting used to if you habitually zoom in and out to compose a shot, but most make the prime transition quite smoothly – mainly because they have to!

So with the terms defined, the choices on display and the fixed focal length accepted, what features should you look for in a macro lens?

Macro subjects abound from the natural world to the world of, erm, DIY! A macro lens really does open up new photography potential.

There are several important factors to consider when thinking about a macro lens that’s right for you. These include focal length, working distance, whether or not it has Image Stabilisation/Vibration Reduction, a Focus Limiter, what its maximum aperture is, how fast and accurately it focuses and probably ultimately how much you want to pay! Let’s deal with each one of these things.

Focal Length and Working distance
We’ve put these first as they are probably the first considerations you have when it comes to choosing a macro lens. As we are talking about 1:1 ratio prime lenses, we’re assuming focal length is fixed. If you look at what’s available you’ll see that you have all sorts of fixed focal lengths to choose from. As we’ve already said, you need to consider the crop factor of your camera when it comes to choosing the perfect focal length so keep that in mind.

What you need really depends on what you expect to shoot most of all. Basically the shorter the focal length, the closer you need to be to your subject when shooting it at life-size. Why does this matter? It probably doesn’t when it comes to photographing inanimate subjects such as leaf details, although even here you have to consider whether the lens could throw a shadow over your subject when held really close. Actually, this can happen with any macro lens but clearly the closer it is to your subject, the more there is the potential for this to be an issue.

Of course, how close you are to your subject becomes even more important when you consider what the subject is. While a stealthy and well-timed approach to ‘spooky’ insects like butterflies means you can often get really close, having a bit of distance between you and them is a bonus. There is even a safety aspect to consider if you want to use a macro lens to photograph insects and other small animals that can sting or bite.  How close do you feel safe?

Ultimately a ‘middle’ focal length of around 100mm (taking into account any crop factor) probably gives you the best of both worlds. Macro lenses around this focal length – 100mm, 105mm, 85mm, 90mm – are your most versatile and this is what we’d recommend for general macro work.

Shot with a 100mm macro at f/5.6 to create some diffusion in front of, and behind, the butterfly. Focus was on the front of the butterfly so this is where it's critically sharp.

Image Stabilisation/Vibration Reduction
While some cameras have in-built image stabilisation systems making it irrelevant in the lenses that go with it, those of you without this will want to consider IS/VR when it comes to choosing a macro lens. A lot of the time you will be using a tripod – which in itself is an image stabilisation system. This will make a difference because you want to avoid camera shake as much as possible with macro photography because if you make the slightest mistake with a macro lens that fault is obvious to anyone looking at your image. That said, you won’t always be working on a tripod. Sometimes it’s impossible and this is when IS/VR can make a big difference so if you can afford it, get a lens with it included, although it tends to push the price up.

Using a tripod while shooting this water boatman (Corixidae) was impossible because of the positioning necessary over the water, so Image Stabilisation helped enormously while holding the lens in an awkward and uncomfortable position.

Focus Limiter
As the name suggests, a Focus Limiter (and you probably have one on your telephoto lens too) limits the range over which the autofocus searches. In doing so, it can speed up the time it takes to lock focus and so it’s a useful function to have, if not absolutely essential.

Maximum Aperture
Since we are talking about prime lenses here, most macros have a wide maximum aperture, often f/2.8. Since at f/2.8 a macro lens will give you an incredibly shallow depth-of-field, what’s the point? Well for starters, a shallow depth-of-field can be used very creatively so it’s worth it just for that! But there’s also the fact that a macro lens can be used as a portrait lens too, and a portrait on a macro at f/2.8 can give you a lovely drop off in focus from the eyes. There are also general ‘fine art’ nature shots that aren’t macro as such but using a macro lens with a wide aperture can give you some really interesting images.

Shooting at f/2.8 on a macro lens can help you get creative with depth-of-field.

When shooting an inanimate object with a macro lens we recommend using Live View and focusing manually to be 100% sure that your point of focus is precisely where you want it to be. Clearly, with a moving subject this isn’t possible so fast and accurate focusing is needed. Not all macro lenses have this! Some have a tendency to ‘hunt’ for focus and when shooting a subject close-up this can be very frustrating. When you’ve narrowed down the lens you think fits your needs best, check out its reviews (or better still see if you can find a Foto-Buzzer who uses the lens and ask them) and see whether this is an issue. Most lenses will lock focus well in good light with a subject that has a lot of contrast so the real test is in poorer light with a less ‘distinct’ subject! You may not find a lens that won’t hunt occasionally for focus in really difficult lighting, but you want to avoid a lens that does it most of the time – or your time in the world of creative macro won’t last very long and will end in tears as you break the offending lens over your knee in frustration!

Simply put, the more features, the better the lens is at focusing and the greater the image quality, the more you pay. That said, while many people like to buy the specific lens created by the camera manufacturer, there are several makes of macro lens that have good third-party lenses built for different lens mounts. You can consider Sigma, Tokina, Tamron and Samyang among your Third Party options, although Canon and Nikon users will have more third-party options than most. It’s also worth considering second-hand models – although unless you know the person selling the lens it may be better to do this through a reputable trader such as MBP where you have more rights if the lens doesn’t turn out to be quite as advertised.

Overall, by investing in a macro lens, you’re adding an optic to your collection that extends your photographic options much further than you’d think. Although it is a highly-specialised lens, it is also a great workhorse for short-telephoto duties like head & shoulders portraits or architectural details. Its close-focusing abilities may seem to be solely for nature studies with forensic detail, but its unique view on the world makes it the go-to lens for textures and abstracts. The other thing – and perhaps most important of all – is that possessing a macro lens means you can never be frustrated by the light conditions, the weather or even the accessibility of a location. When you open up the small-scale world that a macro lens reveals, you ALWAYS have something to shoot. And that – in itself – is quite inspirational.

Published in Camera Skills

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