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Introduction

Pentax smc DA* 55mm f/1.4 SDM is one of the latest addition to the company's growing portfolio of lenses specifically designed for digital SLR cameras. This is also one of the first KAF3 mount lenses in the company's potfolio. As a reminder, KAF3 mount lenses do not have screw slot on the base of the lens mount and hence can only be used in AF mode only on cameras that have electronic focusing control. The lens  was first announced at PMA2008 and made it into production runs by the end of the same year. The lens currently retails for ~US$700 and at this price level is obviously targeted towards prosumers and professionals rather then the masses.

The optical construction of the lens consists of 9 elements in 8 groups. The build quality of the lens is decent, but not particularly spectacular - the barrel is plastic and leaves impression of a cheapo finish, although the lens is actually dust and weather resistant. The lens incorporates a supersonic drive motor for autofocsing, although you can still manual-focus the lens using the dedicated focusing ring. Like most modern Pentax lenses, smc DA* 55mm f/1.4 SDM incorporates 'Quick-Shift Focusing System', which allows you to fine-tune your focus manually after the AF system acquires the target.

For a fast standard prime, smc DA* 55mm f/1.4 SDM is about average in size and weigh, measuring 70.5 x 66mm (2.8 x 2.6in) and weighing 375g (13.2oz). The minimum aperture level is f/22 (again, the aperture settings are controlled electronically from the camera and there is no dedicated aperture ring) and the minimum focusing distance is 45cm (17.7in). The lens accepts 58mm screw-in type filters and since the front element of the lens does not rotate, you can use circular polarizing filters without any problems.

Like all modern Pentax lenses, the smc DA* 55mm f/1.4 SDM was designed specifically for Pentax APS-C type cameras and cannot be used  on older, film bodies. The lens also cannot be easily adapted to alternative mount systems since it does not have a dedicated aperture ring, so while it might be possible to mount the lens using an adapter, the lens would have to be operated only with wide open aperture. Since Pentax APS-C bodies have a 1.5x crop factor, the field of view of the lens on such systems will be similar to that of a 82mm prime on a traditional full frame camera).

 

Summary
Lens Composition 9 elements in 8 groups
Angular Field ~28 degrees
Minimum Focus 45cm/7.76in
Focusing Action AF/MF
f-stop Scale f/1.4-f/22, manual/electronic
Filter Size 58mm
Lens Hood PH-RBH (included)
Weight 375g/13.2oz
Dimensions 70.5x66mm/2.8x2.6"
Lens Case S90-100 (included)