100mm Macro Lenses: Verdict
True macro photography is achieved when the recorded image is the same size as the photographed object. This provides a reproduction ratio of 1:1 and can only be realised using specialist lenses such as the five that are on test here.
Inevitably, the camera has to be positioned very close to the object for true macro photography and this in turn can make lighting the object difficult. That is why a front-mounted ring-flash is often preferred for extreme close-up work.
On the other hand, it is often very convenient to be able to reach the object from behind the camera as this allows fine adjustments to be made to the composition or object distance whilst simultaneously observing the effect through the viewfinder. Combined with the first demand for sufficient working space, it turns out that the ideal choice for macro photography is often a lens with a focal-length of around 100mm.
Macro lenses are tested in terms of their suitability for both large-scale and close-up work. An improvised macro-MTF test has been devised to quantify close-up performance, but this is the first time that such a test has been attempted in this way and its results must therefore be treated more lightly than is the case for conventional MTF testing.