The SMC Pentax-DA ★ 16-50 mm f/2.8 ED AL [IF] SDM has been tested with a Pentax K-3II - French Version
This Pentax DA ★ 16-50 mm f/2.8 was first tested on Pentaxklub in january, 2016 . However, in August, 2020, we decided that some lenses would be re-tested. After the D FA 24-70 f/2.8, here is a new test of its « alter-ego » (but not necessarily equal) for APS-C format. This, of course, in anticipation of the arrival, announced by Ricoh for early 2021, of a new 16-50 mm f/2.8 with PLM motorization and which, consequently, will not be dedicated to all APS-C cameras.
The catalogue price of the SMC Pentax-DA ★ 16-50 mm f/2.8 ED AL [IF] SDM does not make it a « kit lens ». However, at least from a theoretical point of view, it is the ideal standard lens for APS-C cameras. In other words, the lens can be used in most situations, as can a D FA 24-70 mm f/2.8 on a full-format body.
Overview of the SMC Pentax-DA ★ 16-50 mm f/2.8 ED AL [IF] SDM lens
Even if reduced to its full format equivalent, the range of this zoom goes from wide angle (16 mm equivalent 24 mm) to short telephoto lens (50 mm equivalent 75 mm). This amplitude barely greater than 3 (ratio between high and low focal length), puts it in the category of the best zooms.. In terms of results, of course.
Focusing, which is done internally (IF = Internal Focus), prevents the lens from extending during the focusing process. On the other hand, unlike its « brother », the DA ★ 50-135 f/2.8, it lengthens by about 4 cm when changing focal length from one end of the range to the other.
Even if the indication does not appear in its « official » name, it is an « AW » (All Weather) lens built to be usable in difficult conditions : dust, rain, snow. But, obviously, it is not waterproof underwater! Should it inadvertently fall into the water, an immediate « rescue » should limit or even eliminate any risk. But, in any case, it is better to avoid these situations with all lenses and bodies that are not originally designed to work in water.
Lens hood and filter mount
The sunshade is equipped with the traditional Pentax trapdoor. This allows the photographer to operate a polarizing filter, even when the lens hood is mounted on the lens.
Please note, moreover, that the filter mount does not rotate, neither when changing of focal length nor when focusing.
The weight of the Pentax DA ★ 16-50 mm f/2.8 is 565 g, which is equal to that of one of its rivals, the Sigma 17-50/2.8, but greater than the weight of another competitor, the Tamron 17-50/2.8 (430 g). Note that these two rivals are no longer manufactured in Pentax mount.
There is no discomfort when used on any Pentax APS-C body. The body/lens balance is very good and the weight of the package is very acceptable to most photographers. But it is not usable on a FF camera other than in APS-C crop mode: the optical circle is strictly that of an APS-C and does not cover the 24×36 sensor. We would obtain images bordered by a dark circle, even in crop 1:1. (see below « With a full frame body »).
Its minimum focusing distance (0.30 m) is very comfortable and in some cases, at the maximum focal length, even allows for close-up photography, not quite what is known as « high proximity photography » (in french, we call that «proxi-photographie» ). Of course, it is not the ideal lens for this purpose, because of the magnification ratio which is only about 1:5 (0.21x).
Main technical data of the DA ★ 16-50 mm f/2.8
The STAR (★ ) lenses
At Pentax, the ★ (STAR) leses are the top line in terms of performance. Not only in terms of pure performance (optical quality, sharpness, homogeneity), but also in terms of manufacturing, with quality materials that offer both sturdiness and high end features.
Talking about the sturdiness of the DA ★ 16-50 mm f/2.8 can bring a smile to your face. Those who have owned a « problem » copy will probably give a bitter laugh. And yet! It was designed as a top-of-the-line model, but at the time of its introduction (2007) the standards were not yet what they are today.
The optical formula
The optical formula is shown in the diagram below :
As can be seen, the optical formula of the DA ★ 16-50 mm f/2.8 includes :
- 2 ED (Extra-low Dispersion) glass lenses : their main role is to eliminate chromatic aberrations as much as possible by avoiding light dispersion. Usually, the consequence is sharper images.
- 3 aspherical lenses: their use makes it possible to design smaller (and lighter) lenses. They correct coma and optical aberrations, especially in wide-angle position. The coma (from the Latin coma, comet) is an aberration that forms on images that are not exactly in the main axis, so especially on the edges.
The diaphragm has 9 blades, as often (but not always*) in the ★ series. For macro lenses, this makes the bokeh more « creamy ». For others, such as this DA ★ 16-50 mm f/2.8, it makes the transitions between the different planes of a photo smoother and more progressive.
The ★ (Star) series from Pentax is known, among other features, for its high manufacturing quality.
The bayonet is made of metal, which is obviously machined with the utmost precision to avoid any backlash. No criticism to be made on this point.
The barrel is mainly made of polycarbonate, but it is of high quality. It has no « economic » aspect. The focusing and zooming rings, covered with a rubber coating, are well designed: their handling is pleasant and easy, their width is adapted to all kinds of hands.
The SDM engine now appears to be very outdated, not in terms of precision, but in terms of speed of operation, by the latest Pentax productions. We will not enter again into the controversy that has surrounded this objective for years. We’ll just remind you that a proportion, certainly a minority, but too important in absolute value, of specimens of this objective has known very big setbacks with repeated failures of the SDM motorisation. The reader may, on this subject, refer to our study on the problems of the Pentax lenses (french version only). In particular, he will find links to sites offering a procedure
to bypass the problem by reprogramming the lens’ EEPROM. On the other hand, its silence can be underlined.
The DA ★ 16-50 mm f/2.8 benefits from the « Quick Shift » feature. For those of you who may not be aware of it, this allows you to manually adjust or slightly change the focus after the AF has been performed. This is a comfort feature that can be used in many situations. However, this requires that handling of the focus ring is sufficiently flexible and precise. Here, this is the case.
Main optical data
PENtaxKlub does not have a laboratory. Our tests are not measured by tools. We wish to bring a user and essentially photographic point of view. Our comments and technical note are therefore the result of a visual analysis.
Please note that for any lens, even the best one, it is always possible to obtain visual imperfections (especially with ACs), whatever the focal length and/or aperture.
All the photos used for the tests were taken in RAW (DNG). Unless explicitly mentioned, undeveloped and unretouched.
Note : For all pictures, the shooting conditions are as follows:
- camera on a tripod, in M (manual) mode, AF assist enabled
- remote control release (after aperture and exposure adjustment)
- focusing using only the central collimator
Chromatic aberrations (CAs) and Flare
Any lens is likely to produce chromatic aberrations (CAs) and flare.
CAs appear as a purple (or green) fringe, unpleasant to the eye. They form when the 3 colors of white light (Red, Green and Blue) pass through a lens, separate and do not meet in the right place to produce a sharp image.
Flare occurs in certain light conditions, such as when the sun sends its rays at an angle to the lens.
This is why we prefer to judge a lens in common and not exceptional image situations.
Examination of the above images, including 100% excerpt, leads to the following conclusions.
They are well present at the 16 mm focal length and at full aperture, especially all around the light source, on the edge of the sheets. They fade when moving away from the light source. However, they are still present, but much weaker, at f/5.6.
At 50 mm focal length and at full aperture, if there are still some traces of them, they are much weaker and therefore easier to correct. At this focal length and at f/5.6, they have completely disappeared.
At the minimum focal length and at full aperture, there is flare in the area close to the light source (contrast reduction) and also stray light traces, especially in the excerpt immediately to the right of the word « Klub » in the watermark). Of course, this trace is also visible on the whole image. At f/5.6, this flare is accentuated and becomes even more visible, even though the angle at which the photo was taken is the same.
At 50 mm, it is not really detectable. To see it, you must observe the excerpt at 100% at full aperture and note less contrast near the light source, which is normal. At f/5.6, everything returns to normal.
PentaxKlub recommends the systematic use of the lens hood to limit as much as possible the emergence of flare. And incidentally, this is a first protection for the front lens.
In the shooting conditions (see below, « Distortions »), vignetting is important at the shortest focal length, from full aperture (f/2.8) to f/4. Slightly visible at f/5.6, it then disappears.
At 24 mm, it is negligible at all apertures. Curiously, it reappears at the longest focal length (50 mm) and at the full aperture, and is non-existent at the other apertures.
As for its treatment, most good post-processing software will be able to make it disappear if necessary.
The shooting conditions were as follows:
- outdoor shooting in « mixed » weather, and changing lighting, which explains the variations in colorimetry.
- camera on a tripod at a constant distance (approx. 4 m), regardless of the focal length
- remote control release
The above images would almost be sufficient on their own. In addition to the vignetting noted and explained above, there is an extremely significant barrel distortion at 16 mm, whatever the aperture, which has no effect on the phenomenon. Moreover, this distortion is not regular, with considerable differences between the top and bottom of the picture. In other words, correction at this focal length will present huge difficulties, unless the edges of the image are trimmed to a large extent.
The results are clearly better at 24 mm and even better at 50 mm, although the situation is not entirely satisfying.
Of course, in real shooting conditions (landscape, in particular), this distortion will not cause any major problems and will be acceptable. This means that this lens will not be able to be used in all shooting situations, especially geometrical shapes (close up architecture, rectangular objects,…). Except to be satisfied with imperfect images or to post-process patiently, at length and with great care.
Homogeneity and sharpness
The shooting conditions are the same as for test images (see above).
Usually, picture homogeneity and sharpness are not a big problem with fixed focal length lenses. At least for those that have been designed for digital use. Provided, of course, that the photographer does not neglect his focus adjustment. Of course, there are exceptions, but they were much more frequent with the lenses for film photography, which favoured the centre of the picture, to the detriment of the periphery.
This is not the case with zooms. It’s then much more difficult to compose an optical formula that ensures the homogeneity and sharpness of the picture over the entire field of view, whatever the focal length.
This Pentax DA ★ 16-50 mm f/2.8 is, at least partially, an illustration of this.
Analysing the pictures
Whatever the focal length, the sharpness in the centre of the picture appears to be correct, with a small flat at 16 mm f/2.8. The enlarged image is rather sharp in the centre with, however, when you move away from it, a certain lack of vividness leading to an impression of blur. At this focal length and at the same aperture, the edge leaves no doubt: it is rather blurred and without relief. At the following apertures (from f/4 to f/8), the situation improves considerably and progressively both in the centre and at the edge of the image, with however always a slightly less good level at the edge. Nothing serious though. We conclude that, at 16 mm, the full aperture should be avoided, when it is possible.
The situation is much better, whatever the aperture, at 24 mm, but not perfect at f/2.8. And, of course, it improves at smaller apertures. The edge, which is still a bit behind at full opening, still becomes very usable from f/4 onwards.
At 34 mm and 50 mm, although the full aperture shows, as one would expect, a notch below what is considered excellent, the overall homogeneity does not give rise to strong criticism.
To sum up on this point, provided that the larger aperture at 16 mm is avoided for close subjects, the Pentax DA ★ 16-50 mm f/2.8 will, in most situations, give very good quality pictures. Such a zoom cannot be expected to have the precision of a macro lens.
With a full frame body
Like most Pentax DA zooms, this 16-50 is not compatible with the full format (24×36), regardless of focal length and aperture. Vignetting is so important that it « eats » a large part of the image. Of course, it fades as the focal length increases, but even at 50 mm, it remains very visible, even in 1:1 crop. The pictures below illustrate this.
Price and Competition
At the time of writing this new test of the Pentax DA ★ 16-50 mm f/2.8, its catalogue price, excluding promotions, is €1,099. This is a sum that very few photographers are nowadays ready to spend on a lens that has undergone so many misfortunes.
On the new-build market, with comparable quality, the 17-50 f/2.8 from Sigma is the only competitor, at less than 350 €, but available for how much longer? Probably the time it takes to sell out existing stocks at retailers who still have them, because Sigma, as our readers know, has decided to abandon the K-mount.
On the second-hand market, you can also find this same Sigma at an attractive price, as well as its counterpart (in terms of focal lengths) made by Tamron. But neither is protected against weather and/or dust (neither AW nor WR). So they cannot compete with the Pentax on this point.
In fact, if there is any competition, it could still be found at Pentax either with the DA 17-70 f/4 (now discontinued, but still available on second hand), or with the very good DA 16-85/3.5-5.6. However, everyone will have noted :
- that these are not lenses of the Star series
- that the maximum aperture is not as large as that of the DA ★ 16-50 mm f/2.8 and that, in addition, on the 16-85, it varies with the focal length.
We are therefore eagerly awaiting the announced version II of this zoom, probably very much improved in terms of motorisation (PLM instead of SDM), but at a price that is undoubtedly higher and reserved only for KAF4 compatible bodies. The medium-term future will tell us more.
The Pentax DA ★ 16-50 mm f/2.8 is, overall, a zoom lens of outstanding optical quality and it produces highly accurate pictures with faithful colourimetry. It is particularly suitable for use in everyday circumstances : landscape, street photography, portrait (it is the equivalent, in framed field, of a 75 mm on FF body). This zoom can also be used for close-up photography (minimum focusing distance at 30 cm). In short, an intrinsically very versatile lens.
One might think, on reading this « balance sheet », that this lens must be avoided. Having owned a copy of it for 4 years, I think it would be a mistake. Many considered my copy to be exceptional. In any case, used in good light conditions, the DA ★ 16-50 mm f/2.8 will satisfy its owner in most cases. Let’s also do it justice : newer models produced after 2012 are much less prone to motoring problems than those produced earlier.
But, of course, everyone has the right to prefer one of its competitors whose quality/price ratio is, no doubt, superior.
|Handling||10||Perfect and well thought-out: the DA 16-50 is easy to use.|
|Construction & Finition||6||Construction and finishing are exemplary, even 13 years after the market launch.|
|Technical specifications||10||Without any reproach again: the presence of the quick-shift is a very useful advantage.|
|Image quality (homogeneity, sharpness, distorsion)||27||The sharpness is excellent, especially in the centre of the picture, but the edges are recessed. Huge distortion at shorter focal lengths.|
|Optical quality (Aberration, flare, vignetting)||25||CAs are relatively easy to correct. Flare can be avoided. Vignetting can also be corrected, but it is too important at short focal lengths and at larger apertures.|
(*) The recent DA★ and D FA★ have all been fitted with 9 diaphragm blades, some FA★ as well. But others FA★, F★ and A★ have « only » 8 diaphragm blades.
(Note : some of the pictures below were taken with K-5 and K-5 IIs bodies)
Photo credits : © Micaz – The pictures are the property of the author (unless specified) – Click to enlarge