Some photographers love using macro lenses for portraiture. Others hate it. The choice of using a macro lens when shooting portraits thus becomes an individual one which has a myriad of upsides and downsides which we will cover in this article.
For me, a macro lens begun my career as a portrait photographer. Before I ever pointed my camera at a human, I was an obsessive, hobbyist, nature photographer who mostly shot landscapes. At the time I had borrowed my dad's old Nikon 35-70mm f/2.8 macro to experiment with shooting nature much closer than I was used to. Despite that lens making for a terrible macro lens, I quite enjoyed the new experience of shooting tiny nature instead of massive nature. Thus, I purchased the Tokina 100mm f/2.8 macro, which I used for shooting itty bitty things briefly until I started experimenting with portraits, which quickly led me to leaving nature photography in my rearview mirror.
Why Macro Lenses Make Great Portrait Lenses
A true 1:1 macro lens makes for a phenomenal portrait lens in many ways. Especially for photographers who primarily are aiming to shoot relatively close portraits such as headshots.
Macro Lenses Have Outstanding Detail
As a lens that is designed to capture the tiniest of details, macro lenses are notorious for rendering some of the sharpest detail. When focus is on point, a good macro lens will resolve a crispness that few lenses can match. This helps create extremely clean, razor sharp images, that make for wonderful prints.
Macro Lenses Often are Available in Wonderful Portrait Focal Lengths
While there are some macro lenses which break this mold, the majority of macro lenses on the market represent focal lengths that are characterized as having a perfect balance of telephoto properties to create flattering portraits. The most common macro focal length is in the 100mm neighborhood which many headshot photographers characterize as being the perfect headshot focal length.
Macro Lenses Focus Close
Have you ever been in a situation when shooting with one of your normal lenses where your camera is hunting for focus with no success only for you to realize you are a few inches too close? I've run into this problem frequently, the composition that I'm aiming for is just a hint closer than what my lens allows. The problem vanishes with a macro lens. You will never be even remotely close to pushing the limits of how near a macro lens can focus when shooting portraits.
Why Macro Lenses Make Poor Portrait Lenses
Unfortunately, macro lenses also include a few rather steep downsides which cannot be ignored when evaluating whether they will be your next portrait lens.
Macro Lenses are Darker
In general, macro lenses tend to be an f-stop or so darker than a non-macro equivalent at the same focal length. The fastest macro primes on the market are f/2.8 wide open. This problem is further compounded by 1:1 macro lenses as they lose maximum aperture as they focus closer than infinity. This is just part of the physics of how a macro lens achieves its close focusing, there is really nothing the manufacturers can do to prevent it. Nikon reports this in camera to let you know what is happening (which might make a new macro user think their lens is not working properly), Canon does not share this information in camera. For example, my Sigma 150mm f/2.8 macro at headshot range is more of a f/3.0-f/3.5 lens when wide open. If you are looking for a lens that is going to offer the creamiest, most buttery, shallow depth of field, a 1:1 macro lens is probably not going to get the job done for you.
Macro Lenses are Slower
Many macro lenses offer a switch to limit focus range to help reduce this problem but one reality of having a much greater range of focus is that the lens has a lot more range to scan in order for autofocus to lock in. This means if you are shooting in situations where fast, accurate, autofocus is priority a macro lens likely is going to let you down. Personally, I've also found, at least in the macro lenses that I own, the autofocus tends to be a bit less accurate than similarly priced non macro primes.
Macro Lenses are Expensive
A macro lens is a specialized, lower volume product for manufacturers, which means it costs more to make, and fewer sell. This means that they generally come with a larger price tag (though there are exceptions, such as the Tokina 100mm f/2.8 macro, which is very reasonably priced).
Macro Lenses Can be "Too" Sharp
Remember that amazing sharpness I mentioned as a benefit? To some it can also be a detriment as that extreme sharpness resolves blemishes and flaws with amazing clarity thus increasing the post production workload. To some photographers that perfect sharpness is critical, to others it is a flaw. If you are in the latter camp, a macro lens is not going to be the lens for you.
Macro Lenses Tend to Suffer from Focus Breathing
Focus breathing is when a lens's focal length seems to slightly change between max focus and minimum focus which effectively changes your frame without moving the camera. Almost all lenses suffer from this to a degree. Of all my lenses, my macro lenses suffer from this the most, presumably because of the extremely long focus distance. For example, my 150mm macro has a frame that is closer to a 135mm lens when focused at headshot range. Which I don't mind at all, personally, as I feel 135mm is the perfect portrait focal length for headshots but it is certainly a flaw worth noting
Macro lenses can make for fantastic portrait lenses, they can also make for poor portrait lenses depending on your needs or priorities for a given shoot. When deciding which portrait lens to buy keep in mind which factors above matter most to you and you will be able to easily determine if a macro lens is right for you.
Personally, even though I own multiple macro lenses, I'm still on the fence about them. In some situations I adore their results, in other situations I find myself frustrated with them. More than anything, however, I think it is about finding out if a macro lens fits nicely into your workflow or not.