What are macro bellows?
A macro bellows attachment is a device positioned between a lens and a camera body. Its purpose is to increase flange focal distance and achieve higher magnification in macro photography. It constitutes of a hollow pleated bellows tube capped with bayonet or screw interface connectors at each end mounted to a rig that allows it to collapse and extend. The setup looks and operates much like a view camera and relies on the same optical principles.
In terms of optical effect, bellows give results similar to extension tubes, but can provide much more magnification. Furthermore, the bellows extension can be continuously adjusted, which can help obtain optimal framing at the desired magnification.
How do macro bellows work?
Macro bellows are used much like extension tubes or teleconverters, in that they go in between the lens and the camera. The bellows would typically have a male bayonet end that attaches to the camera, and a female bayonet mount to which the lens attaches. Before you attempt this, you need to make sure that all the components you have (lens, bellows and camera) utilise the same mount.
A more flexible solution can be found in so-called universal bellows systems. A prime example of such a system is the Novoflex Balpro 1 demonstrated in the video above. It uses a system of adapters allowing the bellows to be attached to cameras and lenses of virtually all formats and brands. For example, you have a Canon DSLR system, but you stumble upon a great deal on a manual Nikon macro lens. To use it on your universal bellows system, you just purchase the corresponding adapter and off you go.
After you have assembled the rig, you would usually need to mount it to a sturdy support system. Geared tripod heads are often used in conjunction with macro bellows. The higher you go in magnification, the more precise you need to be with your composition. Once the rig is assembled and mounted, the necessary extension is set through the bellows support system, which is usually of the rack and pinion type.
What are the different kinds of macro bellows?
By definition, all macro bellows provide adjustable image magnification through increasing the flange focal distance. However, there is additional functionality that can be found on some higher end models.
Most notable is perhaps the tilt / shift functionality of some units. This allows focal plane manipulation, used for perspective correction and the implementation of the scheimpflug principle.
Another, yet rarer feature on some models is electronic contacts for lens control, as seen on the Novoflex unit pictured above.