The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax D-FA 100mm F2.8 Macro and the Pentax D-FA 50mm F2.8 Macro for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is a crucial factor to consider when comparing two lenses. Pentax D-FA 100mm F2.8 Macro is the longer of the two lenses at 81mm. The Pentax D-FA 50mm F2.8 Macro with a length of 60mm, is 21mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 68mm.
The weight of a lens is equally significant as its external dimensions, particularly if you intend to handhold your camera and lens combination for extended periods. Pentax D-FA 50mm F2.8 Macro weighs 265g, 23% (80g) lighter than the Pentax D-FA 100mm F2.8 Macro's weight of 345g.
Below you can find the dimension and weight table of the Macro Prime Lenses in Pentax KAF Mount for size comparison purposes.
Macro Lenses in Pentax KAF Mount for Size Comparison
Filter Threads
Both the Pentax D-FA 100mm F2.8 Macro and the Pentax D-FA 50mm F2.8 Macro have the same Filter thread size of 49mm.
Below are links to the 49mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Pentax D-FA 100mm F2.8 Macro and the Pentax D-FA 50mm F2.8 Macro has the same Pentax KAF lens mount. Some of the latest released cameras that are compatible with the Pentax KAF lenses are Pentax K-3 III Monochrome, Pentax KF and Pentax K-3 III.
Focal Range
Pentax D-FA 100mm F2.8 Macro is a prime lens with fixed focal lenght of 100mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
150mm.
On the other hand, the Pentax D-FA 50mm F2.8 Macro is a prime lens with fixed focal lenght of 50mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 75mm.