Sometimes referred to as diopters, close-up filters screw on to the front of a lens—any lens you like, in fact, although they’re likely to work best on prime lenses—and allow for closer than normal focusing. They’re measured by the strength of the diopter, with a higher number equating to more curvature of the lens and closer focusing. Better still, when close-up filters are stacked, their diopters essentially add—so a .5 diopter atop a 1 diopter filter achieves practically the same effect as a 1.5 diopter effect. They don’t necessarily achieve true “macro” 1:1 reproduction capability in every case, but they certainly make approximating it much easier and more affordable than practically any other approach. The downside of close-up filters, particularly when compared to actual high-quality macro lenses, is that they introduce chromatic aberration, which is amplified when multiple filters are stacked together.
By moving the lens farther from the sensor, the focusing distance decreases, magnification increases and light falls off. This has the effect of making an ƒ/8 aperture function more like ƒ/11, but it also means you can turn any lens into a close-focusing machine with an extension tube mounted between the body and the lens. It can make a macro lens increase its reproduction ratio, but it also means a normal or wide-angle lens can be made to focus extremely close to the subject for extreme close-ups. Not to be confused with tele-extenders, which have internal optics to increase a lens’s effective focal length, an extension tube is hollow and simply moves a lens farther from the sensor without any optical interference. Extension tubes can also be stacked together for use in conjunction. The farther you extend, however, the more the light will fall off. (The Kenko extension tube set shown above retails for about $129.) A similar option to extension tubes is a bellows extender, less common in the digital era but quite popular back in the 35mm film days when these devices were common for duplicating 35mm transparencies. If you can get your hands on a bellows for your DSLR, you can make tremendously close-up images of the tiniest subjects.
Photographers who consider themselves “serious” about their craft will no doubt scoff at the idea of using a smartphone for anything approaching high-quality photography, but the truth is these phone cameras are getting better with every iteration. One of the things they’re most useful for is extreme close-up photography. Their small size makes them very easy to get very close to small subjects, and they can by default focus very close—less than 2.5 inches away in the case of the iPhone 8, for instance. Coupled with the small size of the cameras’ sensors (which always increases enlargement and therefore has the effect of greater magnification in the finished image) smartphones are actually very useful for macro photos. The samples included here, for instance, were made with an iPhone 7 at just over three inches from the subject.
If you don’t want to invest in a macro lens for close-up photography I’m not going to suggest that you invest in a tilt/shift lens instead, but if you already have such a perspective control lens you should know that one benefit is its ability to focus very close. By tilting the lens at an extreme angle, the plane of focus can be made to run closer to 90 degrees from the sensor plane rather than parallel to it. That means the plane of focus runs from the lens and out through the scene—making extremely close focusing possible. (Actually, it makes a band of extremely close and extremely distant focus possible within the same exposure!) It’s not the same as a real macro, but in a pinch, it can provide a great solution for close focusing on tiny subjects.
If you took your 50mm lens off of your camera and turned it around 180 degrees so that the front element was against the opening in the camera body, you might be surprised to discover when you look through the viewfinder that the lens can now focus extremely close. That’s not a practical or safe way to make pictures, however, so instead you can use a reversing ring to mount a normal lens to your camera, backward. You’ll have to focus manually and if your lens doesn’t have a manual aperture ring you’ll have to use it wide open, but it’s a great way to make some funky, close-up macro images. There are even reversing rings called couplers that mount a reversed wide-angle lens to the front of a standard mounted normal lens to provide a similar effect with the benefit of maintaining auto exposure control with the mounted lens. It is, in effect, a very powerful diopter that works like a close-up filter—albeit much bulkier than a regular close-up lens.