The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 90mm f2.8 Macro and the Pentax FA 77mm 1.8 L 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. Tamron 90mm f2.8 Macro is the longer of the two lenses at 97mm. The Pentax FA 77mm 1.8 L with a length of 48mm, is 49mm shorter. Besides being longer, the Tamron 90mm f2.8 Macro also has a larger diameter of 72mm compared to the Pentax FA 77mm 1.8 L's 64mm diameter.
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 FA 77mm 1.8 L weighs 270g, 33% (135g) lighter than the Tamron 90mm f2.8 Macro's weight of 405g.
Filter Threads
The Tamron 90mm f2.8 Macro has a filter size of 55mm whereas the Pentax FA 77mm 1.8 L has a 49mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 55mm filters that we recommend you to consider for the Tamron 90mm f2.8 Macro:
And these are the 49mm filters that we recommend for the Pentax FA 77mm 1.8 L:
Lens Mounts
Both the Tamron 90mm f2.8 Macro and the Pentax FA 77mm 1.8 L 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.
Tamron 90mm f2.8 Macro is also available in Canon EF , Nikon F (FX) and Sony Alpha mounts.
Focal Range
Tamron 90mm f2.8 Macro is a prime lens with fixed focal lenght of 90mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
135mm.
On the other hand, the Pentax FA 77mm 1.8 L is a prime lens with fixed focal lenght of 77mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 115.5mm.