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Ricoh Imaging now offers two full-frame Pentax DSLRs, the K-1 and largely similar K-1 II, so the need for modern, technologically up-to-date lenses that can do these cameras justice is clear.

K-1 and K-1 II users have the choice of decades’ worth of full-frame-friendly glass, of course, but the HD PENTAX-D FA* 50mm F1.4 SDM AW is the newest member of the company’s premium Star (*) range. This particular lens is promised as the first in a new generation of Star optics, which claim to combine centre-to-corner sharpness at even wide apertures, high light transmission and general all-round optical excellence, all with a rugged design and high dependability.

While intended for users of full-frame cameras, the D FA* 50mm F1.4 SDM AW will also happily partner with APS-C models like the KP and K-70. This results in an effective focal length closer to 76.5mm, which brings it a little closer to classic mild-telephoto focal lengths associated with portraiture. Incidentally, the line will shortly welcome another portrait-friendly Star lens, the D FA* 85mm F1.4, the development of which was announced earlier this year.

All pictures by Matt Golowczynski unless otherwise noted.

Key specifications

  • Focal length: 50mm (76.5mm on APS-C bodies)
  • Aperture range: F1.4-16 (In 1/3EV stops)
  • Filter thread: 72mm
  • Close focus: 0.4m (1.3ft)
  • Maximum magnification: 0.18x
  • Diaphragm blades: 9
  • Hood: PH-RBB72 (provided)
  • Length / Diameter: approx. 80 x 106mm (3.1 x 4.2in)
  • Weight: approx. 910g (32.1oz)
  • Optical construction: 15 elements in 9 groups

The optical makeup of the HD PENTAX-D FA* 50mm F1.4 SDM AW comprises fifteen elements in total, with three anomalous dispersion elements spread throughout the array and a single aspherical element at the rear. As is somewhat standard practice among premium lenses of this sort, the lens combines two coatings: a nanotechnology-based Aero Bright Coating II and a more standard multi-layer HD coating, and the pair work to boost light transmission and minimize reflections that could introduce aberrations and/or affect contrast. Also helping with flare control is the PH-RBB72 lens hood that’s supplied as standard.

The lens’s KAF4 mount adds an extra contact to the KAF3 mount to support electromagnetic diaphragm control from the body. Users of every DSLR released since (and including) the K-50 will benefit from this, although unless you shoot with a K-1 Mark II, K-P or K-70 you'll need to upgrade your camera's firmware first. With no physical aperture ring, you’re limited to using the lens at its widest aperture should you mount it on an older body.

Protection against dirt and moisture incursion is provided by eight separate seals, with a red gasket around the metal lens mount to keep nasties out of the camera.

The current standard KAF4 mount drops the aperture lever from the KAF3 mount and adds an extra contact for electromagnetic diaphragm control.

Pentax lenses that claim some sort of dust and moisture protection are sorted into two categories: Weather-Resistant (WR) and the more stringent All-Weather Resistant (AW). This lens sits in the latter camp. The lens is further protected by a flourine-based Super Protect coating on the front element that not only dissuades water, grease and dust from adhering to it, but makes it easier to clean off when it does.

Nine blades form the diaphragm inside the lens, and these are said to keep defocused points of light round from the maximum aperture until F2.8. Elsewhere, the minimum focusing distance of 0.4m is better than average for a lens of this sort, and when used this close to the subject magnification ends up at 0.18x. The lens also has a 72mm thread at its front for conventional screw-mounted filters.

The hood for the 50mm F1.4 can be reverse-mounted on the lens, and doesn’t get too much in the way unless you’re using the manual focusing ring.

A small window in the lens hood can be removed in order to rotate an ND or polarizing filter.

There’s no image stabilization inside the lens as Pentax users can take advantage of this through the sensor-based Shake Reduction system inside their cameras. Combined with that wide aperture, this obviously makes the lens a good candidate for demanding low-light environments.

Is this the same lens as the Tokina Opera 50mm F1.4? Well, the optical construction appears identical, and the two lenses are pretty much the same size and weight, so at the very least it's obvious that they're clearly closely-related. However, the bare specs don't account for the possibility of some mysterious 'special sauce' that Ricoh might have reserved for the Pentax-branded version. Was this lens developed with the involvement of Tokina? Yes, almost certainly. Does it matter? Probably not - and anyway, the slightly cheaper Tokina-branded version isn't available in PK mount, so if you're shopping for a prime for your K-1 II, the question is academic.

Design and handling

At least in terms of its functionality, this is a fairly straightforward prime lens, so its external design is simple. The barrel is essentially furnished with only two controls: a switch that alternates between autofocus and manual focus, and a manual focusing ring. A focus distance window gives its readings in feet and meters.

The AF/MF switch moves very easily and without any stiffness, although this also means it’s somewhat prone to be accidentally knocked out of position. I experienced this frequently when carrying the camera around using a BlackRapid strap, although this is hardly a fault of the lens, rather something to bear in mind if you prefer to carry your camera around in the same way. If you prefer to have the camera strapped around your neck or you’re using it on a tripod, this probably won’t be an issue.

The lens has just a single switch, which is used to toggle between automatic and manual focus.

The focusing ring at the front of the lens is about an inch deep, and it’s finished with a coarse, square dimpled pattern, which makes it very tactile, if not quite as comfortable as the ribbed design common to many other lenses. It’s well damped and works through its focusing range in roughly a third of a rotation. This might not sound like much, but its 80mm diameter means it still travels a fair distance between its extremes.

Fifteen elements is quite a lot for a 50mm F1.4 lens, and that goes some way to explaining its 910g weight. To put it into perspective, that’s slightly heavier than Canon’s EF 50mm F1.4 USM and EF 50mm F1.2L USM lenses combined. As the K-1 and K-1 II bodies each weigh just 100g more, either will do well to support this, but a combination with either body still ends up weighing just under 2kg (a little over four pounds), which is significant. Partly because of the lens’s 106mm length, however, you can support the whole package quite easily, even if you have larger hands.

The plastic lens hood has a deep petal-shaped design and a small removable tab that slides out for easy filter rotation. It can also be reverse-mounted when not required, and, despite its depth, it doesn’t get in the way until or unless you need to use the manual focusing ring.

Autofocus

The lens employs a newly developed ring-type SDM (Supersonic Direct-drive Motor) to handle autofocus actuation. Ricoh states that this generates up to 7.5x more torque than the SDM systems inside previous lenses, and it’s responsible for driving the rear lens group when focusing.

The focusing system is internal, which means that the overall barrel length doesn't change in length at any time during operation. The focus ring supports a 'Quick Shift' focus system that allows you to adjust focus manually once autofocus has been achieved, without you needing to constantly switch between autofocus and manual focus. You can also call upon focus peaking when using live view, regardless of whether you’re using automatic or manual focus.

This is a fairly weighty lens, with a lot of glass inside it. As such, autofocus performance isn't blazingly fast but it's certainly fast enough that photographers using it to shoot static subjects shouldn’t find much to complain about. In good light, on a K1 II focus is swift and smooth throughout its range. It’s relatively quiet, too, although not quite as discreet as some other modern optics.

The wide, nicely-damped focus ring offers a very positive experience for manual focus and can also be used for focus fine-tuning in AF-S mode.

When the lens does have to hunt – whether that’s in darker conditions, against low-contrast-subjects or somewhere else – it typically works back and forth through its focusing range in around a second or so, so if it can’t find focus it doesn’t hang around for long before letting you know. The only time I found this to be an issue was when capturing portraits close to the minimum focusing distance of the lens, where you might miss a crucial moment.

It’s also possible to focus during video recording using contrast-detect AF. This happens very smoothly and discreetly, with a slight clicking as the lens initially attempts to focus, but with no sound as the focusing groups actually moves. Aperture stop-down behavior changes in video mode, drifting smoothly between positions for smoother exposure changes when the lens is stopped down or opened up.