The smc Pentax-DA* 16-50mm F/2.8 ED AL [IF] SDM lens belongs to Pentax-DA* professional series of lenses and designed for Pentax APS-C digital SLR cameras. The effective focal range of the lens (when taking into consideration K-5 IIs’ crop-factor of 1.52x) is 24-76 mm so the 16-50/2.8 should be considered as a standard zoom suitable for shooting wide range of photography genres — from architecture and landscapes to portraits. The lens has constant maximum aperture 2.8 at the entire range of the focal lengths which makes it convenient reportage and/or travel zoom.
Optically this lens is no other than a result of cooperation between Pentax and Tokina companies and is available as Tokina AT-X Pro 165 AF SD 16-50mm F/2.8 (IF) DX for Canon EF and Nikon F mounts. The differences between the models are shown in the table below.
|smc Pentax-DA* 16-50mm F/2.8 ED AL [IF] SDM||Tokina AT-X Pro 165 AF SD 16-50mm F/2.8 (IF) DX (CANON EF)||Tokina AT-X Pro 165 AF SD 16-50mm F/2.8 (IF) DX (NIKON F)|
|Coating:||smc Pentax||Tokina’s proprietary|
|Dustproof and water resistant:||Yes||No|
|AF motor:||SDM (Supersonic Drive Motor)||Micromotor||None|
|Manual Focus Override:||Quick-Shift Focus System||One-Touch Focus Clutch|
|Manual Focus Switch:||AF/MF||None||AF/MF|
|In Production:||Yes||No, discontinued|
As the table suggests, the smc Pentax-DA* 16-50mm F/2.8 ED AL [IF] SDM has proprietary smc Pentax coating, sealed dustproof / water resistant body and Supersonic Drive Motor on top of Tokina’s base model. Manual focus override for Tokina lens is only available after the user switches to manual focus mode which is done by shifting the manual focus ring towards the camera. The Nikon version of Tokina lens has no autofocus motor and the modern Nikon consumer APS-C digital SLR cameras (D3xxx, D5xxx series) are not equipped with screw drive also so the autofocus with those cameras will not be available at all. On the contrary modern reportage zooms are traditionally equipped with ultrasonic autofocus motors to provide fast and virtually silent autofocus operations. It is also worth mentioning that Tokina lens has no optical image stabilization (company’s first stabilized lens — AT-X Pro SD 70-200mm F/4 VCM-S (IF) FX — was announced only in 2014).
By today’s standard Tokina’s model is highly uncompetitive as a reportage zoom, that’s why no wonder that it was discontinued. As for the smc Pentax-DA* 16-50mm F/2.8 ED AL [IF] SDM, it is still in production.
Design and Features
Despite the fact that like most of other Pentax lenses this one is made in Vietnam, the build quality is excellent. The housing is dustproof and water resistant (characteresitic of all Pentax-DA* professional lenses), made of high quality plastic and the mount is made of metal. The lens has moderate weight of 565 g, quite large maximum diameter of 84 mm and length of 99 mm.
The zoom ring is located near the mount. At first glance it looks pretty thin but after some practice you’ll understand that it’s just wide enough. The zoom ring of the tested lens is well dumped, rotates smoothly but probably a little bit tight. The front element of the lens does not move forward spontaneously under its own weight when the lens is tilted down. The front group of lenses moves forward almost at the distance of 4 cm with zooming from 16 to 50 mm.
The manual focusing ring is wide, well damped and rotates smoothly. The angle of rotation is very small but enought for manual focus adjustments through Quick-Shift Focus System. The focusing is internal (as indicated by IF acronym in the lens’ name) so the front element does not move and does not rotate during focusing and you may conveniently use gradient and polarized filters if you really want. The diameter of the filter thread is 77 mm.
Optically the lens is complex and consists of 15 elements in 12 groups including 3 aspherical and 2 ED elements. Aspherical elements eliminate spherical aberrations, astigmatism and coma. Low-dispersion ED elements reduce chromatic aberrations. Both special elements provide sharp and contrast images even at maximum aperture.
The Pentax company did not publish not only the MTF charts but even the optical schemes of its Pentax K optics but after the acquisition by Ricoh Imaging it is possible to visualize the scheme:
The optical scheme of the corresponding Tokina model for the comparison purposes:
The optical elements of the lens have proprietary smc Pentax coating which improves the transmission of the optical system, improves the color rendering and overall contrast of the image, eliminates ghosting and flares. The smc coating is used in all Pentax lenses for K, 645 and 6×7 mounts and also in Asahi Takumar M42 lenses since 1971 and is constantly updated. A special coating is used on the front lens for repelling water and oils. This enables any water and oils on the lens to be easily removed for effective protection of the lens surface.
The diaphragm has 9 blades. The maximum aperture value is F/22. There’s no aperture ring (as with all Pentax lenses designed for digital SLR cameras) so the aperture control is automatic only.
The minimum focusing distance is only 30 cm and allows shooting interesting close-ups especially at widest end.
The lens is not equipped with optical image stabilizator as most of reportage zooms however this is not required because all modern Pentax digital SLR cameras have efficient in-body sensor-shift image stabilization technology.
The buyer receives front and rear caps, stylish case and petal hood PH-RBI 77 mm in the box. The hood can be mounted reversed for storage or transportation purposes.
The lens is equipped with Supersonic Drive Motor (SDM) so the autofocus is virtually silent and very fast with Pentax K-5 IIs camera used for testing. The Quick-Shift Focus System is supported — the photographer can make manual focus adjustments by just rotating the manual focusing ring after the camera has finished the autofocusing. However the AF/MF switch is present on the housing of the lens for the convenience. Anyway there’s no problems with autofocus accuracy when using Pentax K-5 IIs.
The lens works very good in bright direct sunlight with the dedicated PH-RBI 77 mm lens hood. In some situations, when the sun is in the frame, veiling glare and diagonal flares of moderate intensity and small size appear. However the effect is rare.
Thanks to the focal length of 16 mm it is possible to make a beautiful shots with impressive perspective and wide angle of view, but even at 50 mm it is possible to shoot a couple of lovely landscapes.
In my opinion the lens is sharp at most of combinations of focal lengths and apertures, but it’s not surprising itself (because it’s a pro lens) and also because of the specificity of the genre — the aperture must be closed up to F/8 or F/11 and the most of lenses become very sharp at such apertures.
Strong lateral chromatic aberrations at 16 mm is one of the main disadvantages of the lens which appear when the background contains lots of contrast subjects (for example, tree branches, foliage etc). Such effect fortunately only can be seen at the borders of the frame, but in some cases it may impair the visual perception of the image. However this is the usual disadvantage of optics with such focal lengths. Just one click in Adobe Photoshop Lightroom and the problem is gone. The photo of the forest below provided in two variants — without and with corrections of lateral chromatic aberrations using Adobe Photoshop Lightroom 5.6.
As for focal length of 50 mm, there are no lateral chromatic aberrations there.
The lens shows visible vignetting at 16mm F/2.8 but such combination of focal length and aperture almost never used for landscape shooting. With further closing of the aperture the effect diminishes and from F/8 becomes imperceptible.
Thanks to a wide focal range, fast autofocus and with the help of in-body image stabilizator the lens is damn perfect for street shooting.
The lens shows large barrel distortion near the focal length of 16 mm (this is another big disadvantage) but as in the case of lateral chromatic aberrations the distortion could be fully corrected in one click using Adobe Photoshop Lightroom. Strong distortion at such focal lengths is a typical disadvantage even of prime lenses (despite the fact that optical schemes of prime lenses are simplier than of zooms which theoretically makes it possible to correct the distortion better).
The lens is not «wide» enough for this genre of photography — it is difficult to make interesting photos in confined spaces.
The quality of the bokeh is excellent. The background blur is smooth and soft at 50mm F/2.8. Out-of-focus highlights are evenly illuminated and round at 50mm F/2.8 and do not deteriorate at higher apertures.
Despite the fact that maximum focal length of the lens (76 mm equivalent for full frame cameras) is not within the range of classic portrait focal lengths of 85-135 mm, and the maximum aperture is «only» 2.8, the lens is good for bust and facial portraits especially if there is a good character nearby.
The lens shows moderate vignetting at 50mm F/2.8 but it can be autocorrected in Adobe Photoshop Lightroom and after that becomes imperceptible.
The smc Pentax-DA* 16-50mm F/2.8 ED AL [IF] SDM is a very desirable lens which (thanks to its convenient focal range) allows to take pictures in a variety of genres, may it be architecture, interiors, landscapes or portraits. The constant maximum aperture of 2.8 only increases the attractiveness of the lens. However the reach is not sometimes enough at the focal length of 50 mm to shoot wild animals or birds so if you prefer travel shooting then it makes sense to purchase a fast telephoto zoom, f.e. smc Pentax-DA* 50-135mm F/2.8 ED [IF] SDM (which, that is interesting, also exists in Tokina AT-X Pro 535 AF SD 50-135mm F/2.8 DX incarnation for Canon EF and Nikon F mounts) or one of Pentax portrait primes, depending on what kind of genre will prevail.
If the Pentax 18-55 kit lens became a limitation for you and you found yourself planning the purchase of a more advanced lens, it makes sense to buy the smc Pentax-DA* 16-50mm F/2.8 ED AL [IF] SDM and not to make compromises. As Steven Erikson said in his «Gardens of the Moon»: «Ambition is not a dirty word. Piss on compromise. Go for the throat.». Believe me it’s wise to buy a high quality pro lens and enjoy all of its benefits (outstanding image quality, excellent build quality, dustproof and water resistant body, ultrasonic motor) than to buy a slow speed consumer lens (16-45/4, 17-70/4, 18-135/3.5-5.6 etc.) with no real advantages over 18-55 kit which you will be soon trying to sell on eBay.
Author of the review and the photos: Evgeny Artemov, firstname.lastname@example.org
Please be informed: the images which illustrate this review were developed from DNGs in Adobe Photoshop Lightroom 5.6 WITH correction of distortion, vignetting and lateral chromatic aberrations but WITHOUT sharpening and increasing of overall contrast, brightness, saturation and WITHOUT changing of any other settings.