A brief winter review of smc Pentax-FA 50mm F/1.4 @ Pentax K-5 IIs
smc Pentax-FA 50mm F/1.4 is a fast standard prime lens for Pentax 35 мм SLR cameras. The effective focal length of the lens is equal to 76 mm with modern Pentax APS-C SLR cameras which is pretty close to the portrait range of focal lengths (85-135 mm). Thanks to fast speed of 1.4 the lens can be used handheld in low-light conditions.
smc Pentax-FA 50mm F/1.4 is the latest incarnation of 50 mm F/1.4 model in Pentax system. Pentax Corporation also produced smc Pentax-F 50mm F/1.4 (autofocus lens), smc Pentax-A 50mm F/1.4 (manual focus lens with automatic aperture), smc Pentax-M 50mm F/1.4 (manual focus lens with manual aperture) and, at last, smc Pentax 50mm F/1.4 — the first incarnation of this model for Pentax K mount with the best build quality, manual focusing and manual aperture control.
Design and Features
The lens was made in Japan. The housing is compact, has width of only 37 mm, made of smooth plastic of good quality and the mount is metallic. Overall the build quality is good but not more than that and is significantly worse in comparison with older all-metal smc Pentax, smc Pentax-M and smc Pentax-A models. Despite the usage of plastic the lens is only marginally lighter (220 g) in comparison with smc Pentax-A (235 g).
The exterior of smc Pentax-FA 50mm F/1.4
The mount of smc Pentax-FA 50mm F/1.4
The manual focusing ring is narrow (5 mm only), located at the frontmost part of the housing, not damped well and rotates very easy, without any significant resistance. The angle of rotation of the ring is 130 degrees and that is pretty enough to provide accurate focusing. The ring is not so convenient as that of older manual focus models — its width was decreased almost by three times and its smooth surface does not provide proper grip.
The front element moves forward by 10 mm but does not rotate with focusing at minimum distance of 0.45 m. The same goes to the filter thread so the convenient use of polarizing and gradient filters is possible. The diameter of the filter thread is 49 mm.
Optically the lens consists of 7 elements in 6 groups and is the same as earlier F, A, M and K versions. The optical elements of the lens have proprietary smc Pentax coating which improves the transmission of the optical system, improves the color rendering and overall contrast of the image, eliminates ghosting and flares. The smc coating is used in all Pentax lenses for K, 645 and 6×7 mounts and also in Asahi Takumar M42 lenses since 1971 and is constantly updated.
The optical design of smc Pentax-FA 50mm F/1.4
The aperture has 8 blades, its minimum value is F/22. The aperture opening is not circular, but out-of-focus highlights will be almost round with closing down the aperture thanks to the sufficient number of blades. There is an aperture ring which allows half stop aperture control. The ring is inconvenient because it is often jammed so it is advisable to select the automatic aperture control (A marking on the ring).
All in all mechanically smc Pentax-FA 50mm F/1.4 is a big step back in comparison with older Pentax manual focus 50 mm F/1.4 lenses.
The lens is not equipped with built-in motor and relies on in-camera motor so the autofocus is pretty noisy. However it is also very fast and precise even at F/1.4 so there are no serious claims to its work.
Being an old film era lens smc Pentax-FA 50mm F/1.4 does not support Quick-Shift Focus System (direct manual focus adjustment in autofocus mode).
Wide open the lens exhibits soft-effects and lowered contrast but this won’t be noticeable in the night or in low-light conditions. The sharpness and contrast become very good at F/2 and the lens exhibits excellent shaprness onwards.
The quality of bokeh is excellent. The background blur is smooth and soft wide open and with closing down the aperture by one or several stops. Out-of-focus highlights are round at the center of the frame wide open but slightly deteriorate at the edges of the frame due to mechanical vignetting. Their form degrades with closing down the aperture but anyway becomes almost circular thanks to high number of aperture blades (perhaps except for F/2 where characteristic burrs could be observed). Color outlining appears rarely and only in specific conditions.
Shoot with this lens wide open only in low-light conditions otherwise you will risk to obtain soft images with strong longitudinal chromatic aberrations. Being a standard fast lens smc Pentax-FA 50mm F/1.4 is very good optimized for shooting at small, medium and long distances and provides sharp and contrast images with closing down the aperture by several stops. Distortion and lateral chromatic aberrations are unnoticeable and don’t have to to be corrected during post-processing. Vignetting is weak wide open and becomes invisible from F/2.
smc Pentax-FA 50mm F/1.4 despite its age can successfully compete with modern Pentax-DA lenses and provides excellent sharpness across the frame with closing down the aperture by F/2.8. Wide open there is a soft-effect and slightly lowered contrast but the situation improves at F/2 where soft-effect is gone and the sharpness and contrast are very good. Longitudinal chromatic aberrations are strong wide open, noticeable at F/2-2.8 and mostly disappear from F/4. Distortion and lateral chromatic aberrations are simply not noticeable and vignetting is only weak wide open so you can save time during post-processing. The quality of bokeh is excellent — the background blur is soft and smooth and out-of-focus highlights are evenly rendered and round in most cases.
Mechanically the lens leaves more to be desired — the housing is made of plastic, the build quality is good but not more than that and is significantly worse in comparison with older all-metal smc Pentax, smc Pentax-M and smc Pentax-A models. The manual focusing ring is narrow and inconvenient and the same goes to the aperture ring — it would be better to control the aperture from the camera. Despite the presence of autofocus mechanically smc Pentax-FA 50mm F/1.4 is a big step back in comparison with A, M and K versions. Quick-Shift Focus System is not supported and this may be a significant drawback for some photographers.