HD Pentax-DA* 11-18mm F2.8 ED DC AW

Construction and Handling

The HD PENTAX-DA* 11-18mm F2.8 is a zoom of moderate-to-large size. Considering its fast aperture and wide angle coverage, the 11-18mm is fully within expectations regarding size. For instance, it is slightly smaller than both the Irix 11 and 15mm which, even though they are full frame lenses, are primes instead of zooms.

This section will give you a complete tour of the lens, from every angle. You will also see the lens alongside other lenses and mounted on various camera bodies.

Front Element

The front of the lens is surprising, mainly because the glass component is small when compared to the total size. There are no marks or indications at the front.

Optical elements use Pentax’s most recent coatings, both HD and Super Protect. The former offers improved resistance to flare over the already well-regarded SMC coatings of the past, while the latter makes cleaning the front element easier.

The lens uses a huge 82mm filter thread. This diameter is about the largest found on a Pentax DA lens, except for the 560mm. What is impressive is that Pentax managed to make an extreme wide angle lens which can use front filters: most of the competition either relies on rear filters of prevents their use completely.

The lens cap is the standard clip-on type.

Lens Body

The body of the lens is made of metal and includes a few interesting elements. It follows the design language that Pentax has been using for the last several years, and has all the markings of a "Star" lens. The build quality is superb and the assembly tight. There is no wobble, no loose parts and the lettering is easy to read with colored accents.

Starting from the base (at the lens mount) and going up, we first encounter a taper since the lens's mostly cylindrical shape is significantly wider than the mount. Right above the taper is the ubiquitous green ring, followed by the lens' focal length and aperture, engraved in Pentax's minimalist style.

The ribbed zoom ring its right above. Its throw is just shy of 90°, making zooming from one end to the other fast. The ring is wide at 2.5 cm.

Above this is a section bearing three distinct elements. In the center is the focus distance window, with markings in meters and feet. The text is clear on a dark background, making it easy to read.

To the left (when seen from above) is a switch to toggle AF/MF. Common on "Star" lenses, this switch duplicates the one found on the camera.

To the right is a rather more unique element: a focus clamp. Intended in particular for astrophotography but useful in many situations, this clamp does not work like the ones found on macro lenses of the past, by increasing friction. Instead, it disables focus control completely, so turning the focus ring has no effect and focus remains locked in place. The clamp switch is easy to use, with clear movement and a long enough throw to avoid accidental activation.

The focus ring sits close to the front of the lens. Also wide (with a width of 2 cm) and textured, it is easy to use except when the hood is reversed. In that case one must slip the fingers underneath the hood to rotate the ring. The top section of the focus ring bears the gold circle announcing a "Star" lens, with the lens's full name written on it.

One of the most distinctive features of the lens is found just above the focus ring. The DA* 11-18mm is intended for a variety of uses, but one particular use case is astrophotography. In addition to the clamp, the lens features a groove meant to accommodate a lens heater. These heaters might be less known outside the astrophotography world, but are common for astro as they help prevent dew and condensation from forming on the lens. The 11-18mm's groove makes it easier to install a lens warmer, position it properly and keep it in place. Apart from the groove, the lens shape is mostly level to further help in using a heater.

Not apparent is the fact that the lens' materials are specially selected to operate in cold weather. They are conductive to allow better transfer of the heat from the heater towards the internal elements. The lens is rated for operation down to -10°C.

The total length of the lens does not change when zooming. However, inside the lens’ barrel, the front glass element does move a bit, as can be seen on the picture.

Aperture

The Pentax 11-18mm uses 9 rounded aperture blades.

Lens Mount

The lens mount is metal. Anything else (namely, plastic) would be surprising at this price point. The lens is protected against water ingress.

Lens Hood

The lens ships with a petal-shaped, plastic hood. The 11-18mm can use filters despite its wide angle, so the hood follows Pentax's tradition and includes a removable door to be able to easily rotate polarizers of graduated filters.

Compared to other Lenses

Here is the DA* 11-18mm next to the FA 43mm and D FA 28-105mm.

Mounted on Camera

Below are images of the 11-18mm mounted on a Pentax K-1 (full frame) and a Pentax K-30 (APS-C). The lens looks perfectly at home on the either bodies and balances well, even on the smaller K-30.

Verdict

The Pentax DA* 11-18mm F2.8 is all that one can expect of a "star" lens: large, robust, tightly assembled and with no obvious weak points. It should be dependable and serve for many years. the inclusion of unique features, namely the clamp and heater groove, set it apart and make it distinctive.