The 14-150mm puts in a fairly typical performance for a superzoom in our studio tests. It's at its weakest at the extremes of the zoom, but in the middle of the range it does very well indeed. As usual on Micro Four Thirds, distortion is low due to being corrected in automatically software. Overall the lens's characteristics are remarkably similar to the Panasonic Lumix G Vario HD 14-140mm F4-5.6; indeed the only readily noticeable difference is likely to be lack of colour fringing when using the Panasonic lens on a Panasonic body (due to software correction of lateral CA). Wideangle performance is a little weak, though, compared to either the Olympus or Panasonic Micro Four Thirds kit lenses.
Typically for a superzoom, sharpness results are distinctly mixed. At 14mm, sharpness is high in the center of the frame, but the corners are rather soft. In the middle of the zoom range (25mm - 45mm) things get better, with sharpness high across most of the frame. As we've come to expect, though, the performance declines after this, with relatively soft results at the long end, especially towards the corners. Typically for the Four Thirds format, optimum apertures are generally around F5.6 - F8.
Lateral chromatic aberration is rather high at both extremes of the zoom range, but much better in the middle. At the wide end it increases on stopping down, giving broad red/cyan fringing towards the corners of the frame. It diminishes to respectably low levels around 25mm - 45mm, before increasing again at the telephoto end; here it's most pronounced wide open and decreases on stopping down.
We consider falloff to start becoming a potential problem when the corner illumination falls to more than 1 stop below the center. There's really nothing of any consequence to be seen here.
Distortion is being corrected in software, and is therefore very low. There's a little barrel distortion left uncorrected at wideangle (1.2%), but zoom in to 25mm or longer and everything is pretty well perfectly corrected.
| The measured minimum focus distance is a little less than 46cm (in manual focus mode) - a touch closer than Olympus's advertised 50cm - giving a working distance of 29cm from the front of the lens to the subject. Maximum magnification is about 0.25x.
Image quality is pretty good - the whole frame is a little soft wide open, but sharpens up well on stopping down to F8 (although our sample shows some asymmetry with the right side of the frame a little soft). Distortion is minimal, but there's a little red/cyan chromatic aberration.
|Macro - 73 x 55 mm coverage
Focal length: 150mm (300mm equivalent)
Software correction of lens aberrations
A fundamental component of the Micro Four Thirds system design is the use of software to correct certain lens aberrations, most notably geometric distortion. For most users this is completely transparent - the camera corrects both the viewfinder image 'on the fly' and the JPEG files it records. Also, the relevant correction parameters are encoded directly into the raw files, which means that both the software supplied with the camera and industry-standard alternatives (including Adobe Camera Raw and Capture One) will convert them correctly. However users who like to experiment with more obscure raw developers that are unable to apply the requisite corrections will find themselves with distorted images, especially when shooting at the widest angles.
The graphic below shows just how much distortion you can expect to see when working with an unsupported converter. There's severe barrel distortion at wideangle, but by the time we zoom to the next marked focal length of 25mm it's neutralised, and beyond this there's just very mild pincushion distortion (this is a broadly similar approach to that adopted by the Panasonic 14-140mm). Clearly images shot at the widest settings will require correction in almost all cases - not only to render straight lines correctly, but also to match the original viewfinder composition.
Specific image quality issues
As always, our studio tests are backed up by taking hundreds of photographs with the lens across a range of subjects, and examining them in detail. This allows us to confirm our studio observations, and identify any other issues which don't show up in the tests.
The 14-150mm is generally pretty good at dealing with flare, and we saw few problems even when shooting in bright light without the hood. Pointing the camera directly into the sun at wideangle is tolerated pretty well - there's some local loss of contrast, but relatively little in the way of diagonal flare spot patterns. Shooting at the long end of the zoom in strongly backlit conditions (such that the sun is impinging directly on the front element), there's some loss of contrast but nothing fatal.
|14mm F11, sun in corner of frame||150mm F5.6, strong backlight|
Background blur ('bokeh')
One genuinely desirable, but difficult to measure aspect of a lens's performance is the ability to deliver smoothly blurred out-of-focus regions when trying to isolate a subject from the background, generally when using a long focal length and large aperture. While the 14-150mm by its very nature can't deliver quite as blurred backgrounds as superzooms for larger sensor systems, it makes up for this by providing renditions which are generally very pleasing, with smooth transitions to out-of-focus regions.
|90mm F5.5, Olympus E-P2||150mm F5.6, Olympus E-PL1|
|50% crop||50% crop|
Chromatic aberration and corner softness
Our studio tests show that the 14-150mm suffers from pretty high lateral chromatic aberration at each end of the zoom range, which results in colour fringing towards the corners of the frame. On top of this, the corners are a lot less sharp than the center at wideangle. The examples below give an illustration of how this will affect real-world images.
At 14mm we can see impressive detail resolution in the center, but the corner crop is soft with red/cyan fringing. The latter can, as usual, be corrected by many raw conversion programs - we've used our standard processor, Adobe Camera Raw (v5.7) with 'Fix Red/Cyan Fringe' set to -40 - but the corner softness remains.
14mm, Olympus E-P2
|1/1000 F6.3, camera JPEG||100% crop, center|
|100% crop, top left||100% crop, raw + ACR CA correction|
At the long end of the zoom the pattern is similar - the center isn't quite as sharp as at 14mm, but again the corners are noticeably soft with red/cyan fringing. In this case the CA can be corrected in ACR 5.7 with 'Fix Red/Cyan Fringe' set to +40.
140mm, Olympus E-P2
|1/1600 F6.3, camera JPEG||100% crop, center|
|100% crop, top right||100% crop, raw + ACR CA correction|
Not specifically an image quality issue of the lens itself, but certainly one in combination with the camera body, is shadowing of the built-in flash at wideangle. Here the petite forms of the Micro Four Thirds cameras bring something of a disadvantage - the flashes don't lift all that far clear of the lens axis. The 14-150mm therefore gives noticeable shading on all Micro Four Thirds bodies to date.
Below we show the extent of the problem, shooting a blank wall from about 2 meters. The lens casts a shadow on the lower right of the frame when used on the Olympus E-PL1; you have to zoom to 22mm to make this disappear completely (similar results are seen using the Panasonic GF1). Things are better on Panasonic's SLR-style bodies such as the G1 - there's a touch of shadowing at the bottom of the frame, but in this case it goes away at 18mm.
|Olympus E-PL1, 14mm F5.6||Panasonic G1, 14mm F4|
This is by no means unique to Micro Four Thirds; in fact it's not uncommon for smaller entry-level DSLRs to show similar problems with superzooms. But it's certainly worth knowing about, and perhaps keeping your 14-4x mm kit zoom for indoor flash work.
Camera shake / image stabilization issues
During the course of this review we've taken hundreds of shots across a wide range of focal lengths and shutter speeds using both the E-P2 and E-PL1, and one thing that's stood out on examining them in detail is a far higher proportion of images blurred due to camera shake than we'd expect compared to shooting with a DSLR and superzoom lens. This is particularly the case at longer focal lengths (beyond 70mm or so) and slightly marginal shutter speeds of around 1/focal length (i.e. about a stop slower than we might expect to hand hold on Micro Four Thirds, according to the traditional rule of thumb).
The reason for this isn't entirely clear, but it's probably a combination of factors. The 'rangefinder style' Pen bodies require the camera to be held out in front of you when using the rear LCD for framing, in a fashion that is clearly less stable than the conventional SLR 'eye to the viewfinder' pose. We frequently saw images which showed doubling along the short edge of the frame, corresponding to camera movement in the direction of pressure on the shutter button. So it seems likely that the IS system simply struggles to deal with the inevitable camera movement triggered by a press on the shutter release, which ends up being larger in amplitude relative to an SLR due to the less stable holding position (no matter how carefully you hold the camera and press the button).
As this is more a camera and technique (rather than lens) related issue, we're not going to test it in great detail here, but do think it's worth pointing out for potential purchasers. It's also definitely worth thinking about your hand-holding technique perhaps more than usual when using this lens - for example making a habit of finding a wall or table on which to rest your elbows, whenever shutter speeds are dropping too low.
Below are two typical examples illustrating the phenomenon so you can see what we're talking about, shot using IS mode 1 (with the latest firmware versions at the time of testing: E-PL1 v1.1, E-P2 v1.1, 14-150mm v1.0).
|120mm, 1/100 sec F6.3, Olympus E-P2||150mm, 1/125sec F5.6 Olympus E-PL1|
|100% crop||100% crop|