My comments on the 16-85mm

Hi everyone.

I know there are lots of people who are desperately waiting for a lab test of the new Pentax 16-85mm lens. I was in the same boat, but this lens, at least on paper, was what I had been looking for. I have a holiday coming up soon and this one lens will allow me to meet the airline’s strict luggage weight requirements but will cover all the focal lengths I usually use—and more. So I am now a happy owner of this lens.

While you are waiting for a better evaluation, here is my very unscientific, anecdotal review of this lens. I can only compare this to my Tamron 17-50mm, which, I must stress, is known to be decentered. These alignment issues with the Tamron are normally only evident at 50mm, wide open, but I am sure it must subtly affect the image at other settings.

The Pentax 16-85mm is smaller than I was expecting. It is only a little longer than the Tamron, and it feels solid and well made. I have no trouble carrying the camera with this lens on.

The focussing motor makes a very delicate buzzing sound, but it is very quiet compared to a screw drive lens. Focussing speed seems fine, but the mountains I shoot hardly ever move fast. The focusing ring has a nice feel to it and it moves over a very large angle, which should make manual focussing easier. The lack of a distance scale is unfortunate, but it is just not possible with how the focussing system works.

The feel of the zoom mechanism is quite good, although you do encounter a pronounced ‘lump’ in the turning resistance just before the 85mm end of its travel.

Now, as to image quality. Note that I am using a Kr, so I won’t see the same level of detail as images taken with newer cameras if that is important to you.

At 16mm and wide open (f3.5), the image is soft, especially the corners, but I would not describe it as a train wreck. However the image still appears sharper than that from my Tamron at 17mm and the same aperture. There is a noticeable improvement when setting f5.6. From this aperture to f8, the corners improve even more, although the centre sharpness just starts to pass its peak. In this aperture range, the Tamron and Pentax lens produce images of similar quality. After f8 the image quality very quickly degrades with diffraction taking over at smaller apertures.

Even changing the focal length only slightly to 18mm produces a noticeably better result. At this focal length the image is acceptable, even with the aperture wide open, and, again, it has become very useful once you have stopped down to f5.6.

The lens excels at larger focal lengths, even wide open. I was expecting that the longest focal lengths would be there just for marketing purposes, but this is far from the truth. Fully stretched out, the lens performs well at any aperture.

Chromatic aberration is present for the smaller focal lengths, but it is hardly an issue. Distortion is also very noticeable at 16mm, but seems to be all but gone by 18mm. Adobe Lightroom cleaned up both these artefacts after selecting this lens’ profile.

Overall, I am very impressed. The lens seems to produce reliable results with any setting, although the image degrades gracefully as the aperture is opened up at its smallest focal length. As long as you can shoot between f5.6 and f8, you will get a good result regardless of focal length.

In Australia, I wouldn’t say the lens was ridiculously overpriced, but I am sure a modest price reduction over time would be welcomed. If you think the lens is expensive, take out your frustration on the filter manufacturers. This lens takes a 72mm filter and a polarizer of this size costs a significant fraction of the lens price.

The attached montage consist of crops that are all taken from the very upper left corner of the frame and are at 100%. The left-hand shot is wide open at each focal length. It’s a bit of a mix of apertures, but hopefully this might give you some idea of the lens’ performance.