by Klaus Schroiff, published May 2017
Which single lens would you take to a remote island? The answer will, of course, vary according to the individual preferences but many would probably chose a long-range zoom lens. Traditionally such lenses had a problem … or a couple of those – they were rather mediocre. Well, maybe with 2-3 exceptions: the Canon EF 28-300mm f/3.5-5.6 USM L IS, Canon EF 35-350mm f/3.5-5.6 USM L and the Leica 14-150mm f/3.5-5.6 ASPH OIS. This short list (of DSLR lenses) may already give you an indication – long-range zoom lenses of decent quality come also with a hefty price tag. Olympus has just released their new interpretation of the topic – the Olympus M.Zuiko 12-100mm f/4 IS PRO – and yes, it doesn’t come cheap at around 1300 US$/EUR either. However, the price is at least not outlandish when considering the fact that it is a member of Olympus’ professional-grade (PRO) lineup.
The build quality of the M.Zuiko is certainly impressive. The tightly assembled, weather-sealed body is mostly made of metal. While the lens extends quite a bit when zooming toward the tele end of the range, there is no wobbling of the inner lens tube. The zoom- and focus-control rings operate smoothly. Some interested readers expressed their concern about the size and weight. Yes, it is certainly not the smallest zoom lens in the Olympus line-up but, honestly, it can’t be and it shouldn’t be. First of all – bigger is usually better in lens land and this lens is supposed to deliver a superior performance over the usual 14-150mm gang. Plus it has a constant aperture of f/4 throughout the range (vs f/3.5-5.6) and that limits the amount of downsizing compared to its more compact cousins.
The MSC AF motor is pretty fast and silent. As usual manual focusing works “by wire” but you barely notice the difference compared to a mechanically-coupled system. In fact precise manual focusing is probably easier than on most conventional lenses because the focus path is longer.
The M.Zuiko 12-100mm f/4 IS PRO is one of the few Olympus lenses with a build-in 2-axis image stabilizer. Olympus claims an efficiency of a whopping 5 f-stops. Interestingly the IS can be used in conjunction with the camera’s in body-IS – assuming that the camera supports it (Olympus calls it “Sync-IS”) – increasing the efficiency to an insane 6.5 f-stops (claimed). As of the time of this review the compatible cameras include the Olympus E-M1 II , E-M1 (with firmware update), E-M5 II (with firmware update) and the PEN-F. Unfortunately Sync IS is not compatible with Panasonic cameras. I’m a shaker so I don’t quite reach those 6.5 f-stops but there are people up there who claimed they can. In any case it’s pretty awesome but remember that Sync IS is not the solution to all problems – if there’s motion in your scene, the moving objects will get blurred at slow shutter speeds and no IS will help you there.
|Equiv. focal length
|“24-200mm” (full format equivalent)
|“f/8” (full format equivalent in terms of depth-of-field)
|17 Elements in 11 Groups (3x Aspherical, 5xED, 1xDSA, 1xHR, 2xSHR)
|Number of aperture blades
|min. focus distance
|Dimensions (L x W)
|Petal-shaped, supplied, bayonet mount
|Dust- and splash-proof, ZERO coating, Focus clutch, L-Fn button
The Micro-Four-Third system uses an automatic distortion-correction thus from a user perspective, there is little to worry about here. Images only show a moderate barrel distortion (1.8%) at 12mm but there’s barely something to report about beyond.
While most RAW converters as well as cameras (JPEGs) don’t give you a choice, a few still do (e.g Capture One) thus it is possible to verify the original characteristic of the lens. With disabled auto-correction, the Olympus lens shows a massive barrel distortion of 6.9% (!) at 12mm. The situation isn’t quite as bad at other settings though. At the long end, you can spot a medium degree of pincushion distortions. Barrel and pincushion distortions are equalized around the 25mm mark. Lesson learned –
disabling the image auto-correction is not a good idea.
Auto-correction is also applied to the vignetting characteristic. In this case, the system shows a relatively low degree (0.7EV) of light falloff at 12mm at f/4 and f/5.6 and slightly less so beyond. The issue is pretty much negligible at longer focal lengths.
When looking behind the scenes again, things aren’t that rosy anymore – at least at 12mm. The vignetting is very high at all apertures here peaking at 1.8EV (f-stops) at f/4. However, the light falloff is very much reduced at 25mm and 50mm. At 100mm you can traces of light falloff at f/4 again but this is acceptable.
Let me begin this chapter with two statements. It is impossible to design a reasonably-priced long range zoom that can truly play in the same league as high performance zoom lenses with a lesser range or even primes. On top of that comes the fact the we are talking about a lens with a maximum aperture of f/4. Due to diffraction Micro-Four-Thirds has its sweet spot around the f/2.8 mark – at f/4 the quality is already limited by diffraction. If you have a look at the following chart you will observe that the center quality is actually highest at f/4 which is not surprising (due to diffraction).
Keeping the above context in mind, the Olympus M.Zuiko 12-100mm f/4 Pro is actually darn impressive although it doesn’t touch the best performing MFT lenses, of course. The center performance is great at 12mm f/4 and f/5.6. The outer image region is very good even at fully open aperture. The quality is still very decent at f/8 but you should avoid f/11 and beyond (-> diffraction). Remember that f/11 is equivalent to f/22 on full format cameras – you will rarely if ever need such a small aperture anyway. The sweet spot of the M.Zuiko is around 25mm. The center quality is marginally reduced here but the borders/corners are slightly sharper. The characteristic remains roughly intact at 50mm. At 100mm, the center quality is “just” very good. The border/corner is reduced but remains decent at f/4. In order to achieve the best performance you should stop down to f/5.6 here.
The tested sample had a good centering quality. The field curvature is minimal.
Side note: Out of curiosity I repeated the MTF tests at some settings WITHOUT distortion correction. The LW/PH figures were 10% higher at 12mm and 5% higher at 100mm – just to give you can idea that distortion correction is indeed lossy when it comes to the impact on resolution.
Please note that the MTF results are not directly comparable across the different systems!
Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure for sharpness. If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations
Chromatic Aberrations (CAs)
Lateral CAs (color shadows at harsh contrast transitions) are very low and negligible by real-world standards.
You don’t really buy a 12-100mm f/4 MFT lens for shallow depth-of-field applications – remember that we are talking about a “24-200mm f/8” lens in full format terms. However, let’s have a look nonetheless.
Out-of-focus highlights are reasonably well rendered. The inner zone of the discs is slightly nervous and there is a bit of an outlining effect which is getting emphasized the more you stop down.
The rendition of blur in the critical focus transition zone is much better. Background blur (left crop below) is quite smooth and foreground blur is surprisingly silky.
The Olympus M.Zuiko 12-100mm f/4 IS PRO (to the left below) doesn’t really have a true competitor within the MFT system. The lens that comes close in scope may be the Leica DG Vario-Elamrit DG 12-60mm f/2.8-4 ASPH Power OIS (center, to be reviewed next). Obviously the range is much smaller but, consequently, the Leica lens is much more compact and, at least at the wide-end, also faster. If the range of the M.Zuiko is not enough, there are a variety of options. The Panasonic Lumix G 14-140mm f/3.5-5.6 ASPH Power OIS (to the right) may be the best bet but it’s a consumer-grade lens really – which is why it is both smaller and slower.
Visual comparison courtesy of camerasize.com.
There are many ways to judge the results of the Olympus M.Zuiko 12-100mm f/4 IS PRO. If you want to phrase it in a negative way, you may call it a jack of all trades and a master of none. However, that's unfair really. You could also argue that it doesn't show any true weakness and that's quite something considering the range. More so than the charts, the provided sample images may show that you can use this lens at pretty much all relevant settings with very good results at the wide end and still good results at the extreme long end. Lateral CAs are no issue. Vignetting and distortions are handled nicely (albeit somewhat lossy) via image auto-correction. And the quality of the bokeh is pretty decent for a zoom lens.
The build quality is very good and complies to professional standards including weather sealing. Yes, it is a comparatively big lens by it's not a brick either. I was certainly never annoyed by the size/weight during the field sessions. The AF is speedy and noiseless. A differentiator is the image stabilizer. Of course, many lenses have image stabilizers these days so it's hardly a novelty. However, this one is more efficient than most - especially when combined with an Olympus camera that is compatible to "Sync IS". Whether you can achieve the claimed efficiency of 6.5 f-stops or not - it's class-leading in any case - by quite a margin.
So would I take the Olympus M.Zuiko 12-100mm f/4 IS PRO to that remote island ? Yes, I would. Highly recommended (within its scope)!
Price / Performance