An undoubtedly well-made Pentax prime, but does the image quality live up to the price-tag? Read the WDC Pentax SMC DA* 55mm f/1.4 SDM review to find out.
The length of the lens barrel is split almost in half by the manual focus ring, which resides to the fore. Behind it there is a two-position AF/MF slider switch and a depth-of-field window that has markers for f/8 and f/22. Automatic focusing is brisk and allows manual intervention if required; switching to MF keeps the same feel but simply removes the powered option.
Being a DA design, the lens can only be used on Pentax digital bodies (FA lenses are designed for film bodies and DFA lenses suit both types of image capture). The ‘star’ specification denotes a premium level of build quality with an SDM (Supersonic Direct-drive Motor) AF system. Pentax describes the lens as the digital reincarnation of its classic 55mm FA* standard lens and highlights the addition of the latest anti-reflection coatings for increased light transmission. All of this helps to explain its £500 list price and even on-the-street it is unlikely to be found for less than £400.
Ergonomically the lens is a delight to use but technical testing revealed some disappointing fringing at wide apertures, accompanied by some rather low MTF results. From f/2.8 onwards things are much better and the lens performs satisfactorily in the majority of picture-taking situations. The quietness of the lens is particularly noteworthy.
It seems like a shame that Pentax's 55mm fast prime does not have full-frame coverage, but given that there is currently no full-frame Pentax body (other than older film cameras) this may not be such an important gripe. In isolation this would be a good lens once it has been stopped-down slightly, but amid a field of fast primes its slight weaknesses limit its overall score.