Olympus E-P3 Optics
Olympus M.ZUIKO Lenses
The Olympus E-P3 is compatible with any Micro Four Thirds lens, with Olympus and Panasonic together having shipped a total of twenty five lens models at the time of writing (December 2011), or twenty six if you include Panasonic's 12.5mm f/12 3D lens. Olympus has designated their Micro Four Thirds lenses "M.ZUIKO," and so far twelve M.ZUIKO lenses have been released.
The Olympus E-P3 is available in two kits. One kit includes the M.ZUIKO DIGITAL 17mm f2.8 prime lens, a very compact unit which we've found to be a good overall performer. Click on the link to see the full review of this lens on our sister site, SLRgear.com. The other kit ships with a new, smaller version of the kit lens that shipped with the preceding E-P2 system camera. The new lens is dubbed M.ZUIKO 14-42mm f/3.5-5.6 II. Compared to the previous 14-42mm M.Zuiko, this new lens features an updated design for its optics, autofocus drive, and barrel. In our testing of the previous lens, we found that its collapsing design induced some issues with vertical blurring in images shot at shutter speeds of between around 1/100 and 1/200 second. We're happy to report the new lens seems to have solved this issue.
Focal range and maximum aperture are unchanged from the previous lens, but the previous model's collapsing mechanism has been replaced with a new two-stage design. A change in optical formula for the new lens allows a reduction in weight of some 25%, which falls from 150g in the old model to 112g in the new one. Where the previous lens had nine elements in eight groups, including two aspheric lenses, one extra-low dispersion lens, and one high refractive lens, the new model has an updated optical formula with one less element. With eight elements in seven groups, the new design has no ED or HR elements, but adds one additional aspheric element, for a total of three. The new lens also has a smaller barrel diameter of 56.5mm (down from 62mm), but increases the collapsed length from 43.5mm to 50mm. Filter size has been reduced from 40.5mm to 37mm, which should somewhat reduce the cost of filters.
Another significant change in the new lens design is the adoption of Olympus' MSC (Movie & Still Compatible) design, as first seen in the M. Zuiko Digital ED 9-18mm F4.0-5.6 and M. Zuiko Digital ED 14-150mm F4.0-5.6 lenses. Olympus MSC lenses have autofocus motors which are tuned to focus quickly and accurately, as well as silently, making them better-suited for high-definition movie recording. The new design also focuses internally, whereas the old 14-42mm lens design focused externally, with the last element moving in and out as well as rotating while focusing. All of these are encouraging improvements. Minimum focusing distance is unchanged at 25cm, but the maximum magnification is now 0.19x (equivalent to 0.38x on a 35mm camera), versus 0.24x (0.48x equivalent) in the previous design. As with the old design, the new lens has a seven-bladed circular aperture.
Another prominent feature of the new kit lens is the bayonet mount on the front, which sticks out noticeably even with the lens fully retracted. Here's where users can attach one of three accessory lenses: the Fisheye (FCON-P01), Wide-angle (WCON-P01), and Macro (MCON-P01) lens converters. The 14-150mm and 40-150mm lenses can also accept the Macro conversion lens, though there must be some kind of step-down adapter for the 14-42mm lens to work with it, as the bayonet mount on the latter two telephoto lenses are larger, at 58mm.
In addition, no less than nine different adapters make it possible to mount a wide selection of current and historic glass on a Micro Four Thirds camera. Lenses that can be adapted include certain standard Four Thirds, Olympus OM, Leica M / R, Voigtlander VM / Ai-S / PK-A/R / KA, and Carl Zeiss ZM / ZF / ZK types. These adapters generally have some limitations as to compatibility and available features, which will depend on the specific model being used.
Because the E-P3 features in-body image stabilization, Olympus' M.ZUIKO lenses do not themselves incorporate optical image stabilization.
Some Panasonic Micro Four Thirds lenses offer image stabilization and work with the Olympus E-P3, but
note that you have to disable one or the other image stabilization system.
Olympus E-P3 Sensor Cleaning
The Olympus E-P3 features an ultrasonic dust-reduction system, especially important since the E-P3's shutter is normally open for full-time Live View. The system automatically runs at power-up, and unfortunately, there is no option to disable it or run it manually, as it does contribute to startup time. You can manually trigger a dust reduction cycle as part of the pixel mapping process--which also locates and corrects for stuck pixels on the image sensor--but it isn't possible to trigger dust reduction separately through the camera's menu system.
Kit Lens Test Results
Typical zoom range for a kit lens, with above average performance.
|14mm @ f/8||42mm @ f/8|
The Olympus PEN E-P3 is available bundled with an Olympus M.ZUIKO 14-42mm f/3.5-5.6 II R Micro Four Thirds lens. The kit lens possesses a very typical optical zoom range of 3x, and the 35mm equivalent focal range is about 28-84mm, because of the E-P3's 2x "crop factor." Results were very good at 14mm, with strong detail throughout most of the frame. Coma distortion in the trees was low, and chromatic aberration fairly well controlled, with only a hint of flare around some of the white trim. Results were also very good at the 42mm setting, with good sharpness and even less less flare and chromatic aberration. Overall, well above average performance here for an inexpensive kit lens. See below for comments on macro performance, geometric distortion, corner softness, etc.
An average sized minium area, with very good detail. Flash did a fair job throttling down, though exposure is slightly dim.
|Macro with 14-42mm II kit lens
42mm @ f/5.6
|Macro with Flash
42mm @ f/5.6
As with zoom performance, the Olympus PEN E-P3's macro performance will depend entirely on the lens in use. However, with the 14-42mm II kit lens set to 42mm, the Olympus E-P3 captured a fairly average minimum area measuring 2.76 x 2.07 inches (70 x 53 millimeters). Resolution and detail were both very good, with only a hint of softening in the extreme corners. (Most lenses have some softening in the corners at macro distances, and the Olympus E-P3's kit lens has much less than most.) Extreme corners showed a very small amount of light falloff, though that's not unusual. The built-in flash did a reasonable job of throttling down at this close distance, resulting in a slightly underexposed image. Overall, very good performance here.
Low to moderate geometric distortion with the 14-42mm II kit lens in JPEGs, much higher than average distortion in uncorrected RAW files.
When shooting JPEGs, the Olympus PEN E-P3's 14-42mm kit lens produced about 0.5 percent barrel distortion at wide-angle, which is actually a little better than average and only slightly noticeable in some of its images. At the telephoto end, there was almost no visible distortion, only one pixel of pincushion (about 0.03%). This is the tendency for the lens to bend straight lines outward (like a barrel -- usually at wide-angle) or inward (like a pincushion -- usually at telephoto).
To see how much correction is taking place in the camera, we converted RAW files from the above shots with dcraw, which does not correct for distortion. As you can see, at wide-angle, the barrel distortion is very high at about 2.5%, though pincushion distortion at telephoto is very low, almost nil. We expect to see high distortion at wide-angle from smaller interchangeable lenses though, so it's nothing to be concerned about unless you are using a RAW converter which does not understand the embedded "opcodes" to perform distortion corrections automatically. Most RAW converters these days are capable of applying distortion correction automatically, as specified by the manufacturer. (There's going to be some loss of resolution as a result of such correction, because pixels in the corners of the frame are being "stretched" to correct for the distortion. Obviously, a lens that doesn't require such correction, and is also sharp in the corners to begin with would be preferable, but relaxing constraints on barrel and pincushion distortion likely brings other benefits in the lens design, such as cost, size and weight.)
Chromatic Aberration and Corner Sharpness
Moderate chromatic aberration at wide-angle with the 14-42mm II kit lens; lower levels at full telephoto. Some mild to moderate corner softening at wide open.
Chromatic Aberration. Chromatic aberration in the corners with the E-P3's 14-42mm II kit lens was moderate and slightly noticeable at wide-angle (14mm) when wide-open (maximum aperture). At full telephoto (42mm), C.A. was lower, and not as noticeable. In both cases, the color fringing gradually reduces in brightness and width as it approaches the center of the image, where it is practically nonexistent.
The Olympus E-P3 does not appear to be reducing C.A. in its JPEGs, as uncorrected RAW files have similar amounts.
Corner Softness. The Olympus E-P3's 14-42mm kit lens produced some slightly soft corners at full wide angle, with the right-hand-side corners a bit softer than the left, though telephoto performance in this regard was somewhat better. The center was not as sharp as wide-angle, though softness is very slight. There's also some mild vignetting (corner shading), as indicated by the darker corner crops compared to the center.
Good performance for a kit lens here, especially considering the lens was wide-open for these shots. (Corner sharpness generally improves when a lens is "stopped-down" a couple of f-stops below full aperture. See below.)
|14mm @ f/8: Upper left
Softness: Fairly sharp
|14mm @ f/8: Center
|42mm @ f/8: Upper left
C.A.: Moderately low
|42mm @ f/8: Center
C.A.: Very low
Chromatic Aberration. With the aperture stopped down to f/8, chromatic aberration in the corners with the E-P3's 14-42mm II kit lens was moderate but fairly bright at wide-angle (14mm). At full telephoto (42mm), C.A. was less obtrusive, with dull red pixels that halo one side of the target lines and a hint of blue is just visible on the opposite sides. In both cases, color fringing gradually reduces in brightness and width as it approaches the center of the image, though a trace is noticeable at center.
Corner Softness. Corner sharpness is better at f/8, with very little deviation in sharpness from center to corner, at both wide angle and telephoto. Vignetting also improved to the point of being negligible. Again, very good performance from the kit lens.