There is a whole new world of creative possibilities when you start to dabble in macro photography. From the colours and intricacies of small flora and fauna to the unseen geometry of the everyday mundane, macro offers us a new way of seeing the world.
Although you don’t necessarily need a macro lens, it remains the best way to capture close-ups. However, like most things in photography, buying a macro lens is not quite a simple as it sounds.
There are a number of different factors you need to take into consideration before you pay out your hard earned cash. Today we are hoping to help you with that decision with this simple guide.
What’s The Lens Ratio?
Perhaps the primary question you should ask when deciding on a macro is what is the lens ratio. The lens ratio defines how big the subject will be when captured on the sensor. For example, if you shoot an insect that is 20mm long and it takes up 10mm on the sensor you have a 1:2 ratio.
The best macro lenses will have a ratio of 1:1 or less. In other words, they will capture the subject life-sized or larger.
Beware of lenses that claim macro capabilities, these often allow you to focus a little closer than normal but rarely are true macro lenses.
Deciding On A Focal length
Another very important consideration is the focal length of the lens. The vast majority of macros lenses are in the range of 50mm to 200mm. Wide angle macros are very rare and with good reason. The wider the focal length, the closer you will need to get to your subject to get a 1:1 ratio.
If your macro photography is likely to be flowers or inanimate objects, then a shorter focal length may well be suitable. In this case, a macro in the range of 60-90mm should be fine. However, if you plan to photograph insects or other small wildlife, then a shorter focal length may put you too close to the subject.
This, in turn, may scare them away or even put them on the defensive by biting or stinging you. In this case, a better option will be in the 105-200mm moderate telephoto range. The downside of the longer focal lengths is that if your subject moves, it can be more difficult to track them down.
As most of you will know, the wider the aperture, the shallower the depth of field. However the tradeoff is cost. Fast aperture lenses are generally significantly more expensive than slower ones. An increase of 1 stop can often double the price of a lens.
As you are focusing close, all macro lenses will exhibit some Bokeh at wider apertures. However, the faster the aperture, the more pleasing the Bokeh is likely to be.
The other side of this particular coin is that if you go for a longer focal length, you will get a more shallow depth of field for the same aperture if compared to a shorter length.
Your choice or aperture really comes down to your shooting style and of course your budget.
Zoom or Prime?
Whilst the majority of 1:1 macro lenses are primes, there is a significant number of zoom lenses with macro capabilities. These do not offer 1:1 but do allow you to get closer than normal to your subjects, typically 1:3, or even 1:2.
The main advantage of a zoom is its versatility. A lot of macro zooms range from moderate wide to moderate telephoto, making them ideal day to day lenses for general shooting. If you like to shoot close, but are not fussed about going true macro, then a macro zoom may be an ideal option. If, however, you wish to delve deep into the world of the close-up, then you are better going for a true prime macro lens.
Some macro lenses offer image stabilisation. This, of course, adds a price premium to the lens but there is also another factor you should consider. Image stabilisation works well for more distant subjects but has very limited use in close up work.
If you are buying a macro lens that you will use for other types of photography, for example, portraiture, then a stabilised lens may be a worthwhile purchase. However, if the use predominantly macro, save the money and go for a non-stabilised lens.
Macro is a fascinating world to explore. While there are cheaper options than a dedicated macro lens, it remains the best option. Hopefully, some of the advice above will help you decide on what macro lens you will purchase.