Pentax SMC-FA 100mm f/2.8 macro - Review / Lab Test Report
Lens Reviews -
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Special thanks to Rüdiger Neumann for providing this lens!
The Pentax SMC FA 100mm f/2.8 is the predecessor of the current DFA 100mm f/2.8 macro
and as such obviously a discontinued lens. However, this happened fairly recently so
you may still be able to find it in shops here and there (and on the used market anyway).
Typical for all FA lenses it supports the full 35mm format so it can be
used both on film and digital SLRs. On the Pentax K10D its field-of-view
is equivalent to about 150mm (full format).
The FA 100mm f/2.8 macro is a heavy block of a lens. The outer body
is obviously made of metal. The broad focus ring at the front of
lens operates very smooth. Typical for most medium tele macro lenses
it extends significantly when focusing towards short focus
distances. The lens doesn't come with a lens hood but frankly this
is also not needed because the front element is a couple of centimeters
recessed from the filter thread so this "hole" serves as a sun shade
The FA 100mm f/2.8 has no internal AF motor and relies on a slotted drive screw
operated by the camera. It takes quite a while if you feel the need to AF
from infinity towards 1:1 magnification. In other words - the AF is a bit lame,
prone to hunting and fairly noisy. However, macro users often prefer manual focusing
anyway and for mainstream applications you can take advantage of the focus limiter.
When restricting the AF to a range between 0.6m-infinity the AF speed is actually
very fast and leaves nothing to be desired here.
|Equiv. focal length||150 mm (full format equivalent)|
|Equiv. aperture||f/4.2 (full format equivalent, in terms of depth-of-field)|
|Optical construction||9 elements in 8 groups|
|Number of aperture blades||8|
|min. focus distance||0.31 m (max. magnification ratio 1:1, minimum working distance: ~10.5cm)|
|Dimensions||75 x 104 mm|
|Filter size||58 mm (non-rotating)|
|Other features||FREE (Fixed Rear Element Extension) focusing system|