John Riley reviews the new HD Pentax-D FA 24-70mm f/2.8 ED SDM WR full-frame lens, with the Pentax K-1.
Posted: 17/05/2016 - 13:35
Handling and Features
Performance
Verdict
Specification
The HD Pentax-D FA 24-70mm f/2.8 ED SDM WR lens is the second of the new standard zooms for the new full frame K-1 body. These lenses have a tremendous importance for Pentax in that they define from the outset the standards applied to the new 35mm-format system. The 28-105mm lived up to expectations, so let's see how this higher spec lens with bright f/2.8 constant aperture fares.
HD Pentax-D FA 24-70mm f/2.8 ED SDM WR Handling and Features
Clearly heavier and more substantial in build than the 28-105mm, this lens shows the same level of care in its finish and the smoothness of its controls. The wide zoom ring is smooth and positive in action. There is a locking catch that can be operated at 24mm, to prevent the lens extending under its own weight when being carried. Closer to the camera body is the manual focus ring, which is as smooth as the zoom action. It is ideally placed to make adjustment convenient and can be operated after AF has locked to make final tweaks to the focus point. This Quick Shift feature can be very useful, especially at closer distances. The distance scale is under a clear plastic window and gives distances in both feet and metres.
A clip on lens cap is provided and also an effective bayonet fit petal lens hood. Even with modern lens coatings, it is a good idea to always use a lens hood. It reduces flare and increases image contrast. The lens has the latest HD (High Definition) multi-coating, plus an SP (Super-Protect) coating on the front element to repel water, grease and dirt.
AF is achieved with the latest version of the in-lens SDM (Supersonic Direct Motor) system, which is fast and silent. There seems to be no tendency to hunt and the system locks on every time.
Each section within this WR (Weather Resistant) lens is sealed to prevent the ingress of water and dust, so we can continue to shoot in rain and mist, or anywhere where water splashes are likely.
Optical construction is 17 elements in 12 groups. There are three Aspherical elements, three ED (Extra Low Dispersion) and one Anomalous Dispersion glass element. The diaphragm has nine blades, which helps to improve bokeh, the smoothness of the out of focus areas. This is a constant aperture zoom, with a bright f/2.8 maximum aperture, so it is ideal for lower light levels and for calculating flash levels manually.
Closest focusing distance is a useful 0.38m, a magnification of 0.20x. There is an 82mm filter thread. Finally, the lens weighs 787g, or 812g with the lens hood.
24-70mm on 35mm-format equates to 37-107mm on APS-C, and this lens can, of course, be used on all the previous crop sensor Pentax DSLRs. For older cameras, the AF system needs a K10D (with firmware 1.3) or later, otherwise it will be manual focus only. This means that all Pentax bodies from the last few years will be fully compatible.
Pentax lenses are always very simple in use, there generally being no special switches or mechanisms that have to be considered. This lens is no exception and is basically hassle-free. It focuses snappily, zooming and focusing actions are smooth and even and the lens hood clips cleanly into place without having to fiddle with it. Balance on the K-1 is excellent and the combination is easily manageable despite the weight of the combination of lens and body. For Pentax users used to APS-C sized lenses, this new lens may seem large and heavy, but it works well as a unit.
HD Pentax-D FA 24-70mm f/2.8 ED SDM WR Performance
In a similar way to the other new lenses released, the 24-70mm is definitely of the same design ethos. That is, very good sharpness throughout, regardless of aperture, focal length or centre or edge of the image. The degree of balance is remarkable and is clearly intended to make the most of the entire 35mm-format image area.
Pentax HD PENTAX-D FA 24-70mm f/2.8ED SDM WR MTF Charts
How to read our MTF charts
The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges.
The scale on the left side is an indication of actual image resolution and sharpness as LW/PH and is described in detail above. The taller the column, the better the lens performance.
For this review, the lens was tested on a Pentax K-1 using Imatest.
At 24mm distortion is -3.47% barrel, typical for such a wide angle. CA is highly controlled at the centre of the field. At the edges CA is visible, but can, of course, be corrected in software or in the in-camera JPEG output. For the purposes of reviews, such correction is switched off.
At 35mm distortion is a modest -0.141% barrel, which is insignificant in normal photography. CA at the centre is almost non-existent, but it is visible at the edges.
35mm sharpness is pretty much the same as at 24mm, and does not tail off as many zoom lenses do as we zoom into the longer lengths. It achieves very good levels at the centre over all apertures from f/2.8 to f/22. It starts off as good at the edges at f/2.8, is very good from f/4 to f/16 and drops to good at f/22. As with all the focal lengths with this lens, there is a very high degree of consistency between the resolution figures centre and edge which is impressive.
50mm gives us a figure of +1.03% pincushion distortion, very acceptable for most purposes. The CA values are very low centre and edge and any residual fringing can be easily removed.
50mm sharpness remains at the same high level as before, giving very good sharpness from f/2.8 to f/16, both centre and edge. Diffraction sets in at f/22 but we still have very good results at the centre and it is only at the edges that it drops to good levels.
70mm gives +1.45% pincushion distortion, again very acceptable. CA is still very well controlled, although with slightly higher levels than at other apertures. It can still be corrected in software if desired.
70mm sharpness still retains the same very good standard and still shows the even performance across the frame that is evident all through this lens's focal lengths. It remains good at f/22, which is always useful to have as an option even though no lens will perform at its best at such a small aperture.
Pentax HD PENTAX-D FA 24-70mm f/2.8ED SDM WR Chromatic Aberration Charts
How to read our CA charts
Chromatic aberration (CA) is the lens' inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software.
Apochromatic lenses have special lens elements (aspheric, extra-low dispersion etc) to minimize the problem, hence they usually cost more.
For this review, the lens was tested on a Pentax K-1 using Imatest.
Bokeh, the quality of the out of focus areas, is something that we give much more priority to than in the past. The 24-70mm shows lovely smooth transition in those areas and a very pleasant bokeh effect. There are qualities that cannot necessarily be measured in a lens, but the net effect is a very visually appealing image and this lens certainly has that.
Flare resistance is also vital, especially in a wide angle with its relatively exposed front element. It seems that the new Pentax HD (High Definition) coating works very well indeed, and flare was not found in any of the images shot into the light.
Pentax HD PENTAX-D FA 24-70mm f/2.8ED SDM WR Sample Photos
Value For Money
The HD Pentax-D FA 24-70mm f/2.8 ED SDM WR is priced at £1149, although in bundles with the K-1 is can be as little as £1019. Buying with the camera body may well be a good route to take.
The 24-70mm f/2.8 lens is quite a popular choice amongst all the other makers' ranges, although there are none available in Pentax fit at this time. To put the price in perspective, Canon users have the EF 24-70mm f/2.8L II USM (£1400) and the EF 24-70mm f/4L IS USM (£675). Nikon offers the Nikon 24-70mm f/2.8 G AF-S ED (£1399) and Sony the Carl Zeiss 24-70mm f/2.8 ZA SSM II Vario-Sonnar T* (£1349).
Even at its introductory price, and prices inevitably fall with time, the Pentax looks very good value against the other marques.
HD Pentax-D FA 24-70mm f/2.8 ED SDM WR Verdict
Twice the price of the Pentax 28-105mm zoom, but the 24-70mm offers a constant bright f/2.8 aperture and even a slightly higher level of performance. It really is a personal choice, but this lens is a very satisfying one to use and offers lovely results with a very high level of consistency over its entire range.
This is definitely a lens of choice for the Pentax K-1 with its full frame format.
HD Pentax-D FA 24-70mm f/2.8 ED SDM WR Pros
- High and very even sharpness
- Smooth bokeh
- Fast silent AF
- Weather resistance
- Well controlled CA
- Excellent flare resistance
HD Pentax-D FA 24-70mm f/2.8 ED SDM WR Cons
- Quite heavy
Pentax HD PENTAX-D FA 24-70mm f/2.8ED SDM WR Specifications
| Manufacturer | Pentax | |
| General | ||
| Lens Mounts | Pentax K |
|
| Lens | ||
| Focal Length | 24mm - 70mm | |
| Angle of View | 34.5 - 84 | |
| Max Aperture | f/2.8 | |
| Min Aperture | f/22 | |
| Filter Size | 82mm | |
| Stabilised | No | |
| 35mm equivalent | 37mm - 107mm | |
| Internal focusing | No Data | |
| Maximum magnification | 0.2x | |
| Focusing | ||
| Min Focus | 38cm | |
| Construction | ||
| Blades | 9 | |
| Elements | 17 | |
| Groups | 12 | |
| Box Contents | ||
| Box Contents | Lens Hood: PH-RBD82, Lens Cap: O-LC82, Lens Case: S120-150, Lens mount cap | |
| Dimensions | ||
| Weight | 787g | |
| Height | 109.5mm | |
Members gallery photos using: HD PENTAX-D FA 24-70mm F2.8ED SDM WR
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