Panasonic 14-45mm f/3.5-5.6 ASPH MEGA OIS LUMIX G VARIO

(From Panasonic lens literature) Suitable for a wide range of scenes from portrait to landscape photography, the new LUMIX G VARIO 14-45mm/F3.5-5.6 ASPH./MEGA O.I.S. lens offers an zoom range of 14-45mm (35mm equivalent: 28-90mm) while featuring its ultra-compact size and light weight. The aspheric lens element also improves optical performance by minimizing distortion, even at the 28mm wide end.

SLRgear Review
November 11, 2008
by Andrew Alexander

Update: by processing RAW files produced by the G1, we have determined that the G1 does apply some measure of post-processing correction for chromatic aberration, light falloff and distortion. So on a body other than the G1, your results may vary.

In August of 2008 Panasonic and Olympus announced the creation of a new camera mount system known as ''Micro Four Thirds.'' By eliminating the reflex mirror, a Micro Four Thirds mount camera achieves a smaller size than conventional interchangeable lens camera systems. Fast forward to September 2008, and Panasonic unveiled its G1 and two Micro Four Thirds lenses: the 45-200mm ƒ/4-5.6, and the 14-45mm ƒ/3.5-5.6, the subject of this review.

When mounted on a micro four thirds compatible camera, the size of the sensor produces a 2x crop factor, meaning an equivalent field of view of 28-90mm in 35mm film terms. Panasonic is one of the early pioneers in optical image stabilization systems, so it's no surprise that the lens features its Mega O.I.S. technology to reduce the effect of camera shake.

The 14-45mm isn't a ''constant'' lens, in that as you increase the focal length, the maximum aperture size decreases, however the minimum aperture stays the same. The following table reflects the change in aperture with focal length:

The Panasonic 14-45mm ƒ/3.5-5.6 OIS is sold with the G1 as its kit lens. It uses 52mm filters, and comes with a petal-shaped lens hood.

Sharpness
The 14-45mm ƒ/3.5-5.6 produces very sharp images in a wide array of focal length / aperture combinations. At its wide-angle settings (14mm) and used wide open at ƒ/3.5, the lens is very sharp, hovering at about one blur unit with just a hint of corner softness. This sharpness improves slightly and reaches an apex at ƒ/5.6, but doesn't become tack-sharp across the frame. Keep in mind we're looking at a very slight differential between sharpness in the center of the frame and sharpness in the corners: probably something in the order of half a blur unit. Diffraction limiting seems to set in by ƒ/8; image sharpness decreases by a hair, and again at ƒ/11, until ƒ/16 we start to note just under 3 blur units in the corners and just under 2 blur units in the center of the frame. The smallest aperture setting is a uniform ƒ/22 across all focal lengths: I'd avoid this setting as it produces images with 3-4 blur units, regardless of the focal length chosen. That's not bad, but not great in comparison to the very good results for sharpness at larger apertures.

Mid-range and telephoto performance is almost the same as wide-angle performance: excellent performance up until ƒ/5.6, and then a very slight falloff in sharpness until ƒ/16 and ƒ/22. At 45mm, corner softness isn't as much of an issue. I'd say the optimal setting for this lens depends on your application: our best results were obtained at 18mm and ƒ/5.6, but that's splitting the hairs quite finely. The truth is that unless you're looking at the pixel-by-pixel level you're not likely to notice any difference in sharpness except in the absolute corners, or at very small apertures.

In short, for such a small lens, focusing on a relatively small sensor, we see excellent results.

Chromatic Aberration
The 14-45mm ƒ/3.5-5.6 does produce some chromatic aberration, but it's not overly objectionable. Our test chart shows a relatively interesting story (I use the term relatively because I understand not everyone may be interested in the wonders of chromatic aberration). Typically, wide angle lenses show a high degree of chromatic aberration; with the 14-45mm, some of its best tolerance to CA is found at 14mm. Average CA is just 1/100th of a percent of frame height, and maximum (corner) CA hovers under 3/100ths of a percent of frame height.

However, in the mid-range (18-40mm), CA is slightly more visible, tending to show off more with the largest apertures (ƒ/4-5.6). This trend reverses once more when you hit 45mm, where CA is less prominent when the lens is used wide open at ƒ/5.6, and increases until it shows off the most CA at ƒ/22.

I can only imagine there is a complicated dance of lens elements inside the lens to produce these optical results. Fortunately, none of the results is so severe that you actually need to worry about what aperture or focal lengths to avoid, but for best results, the advice would be either 14mm or 45mm, using the wider apertures.

Shading (''Vignetting'')
Unfortunately, or testing software couldn't contend with the G1's image files when it came to calculating corner shading. Looking at the sample images is fairly useful in this regard: to my eye, corner shading isn't a big issue, apparently only (as is typically the case) at 14mm and ƒ/3.5. I would take a big guess and say we're looking at corners that are about a half-stop darker than the center at these settings.

Distortion
Panasonic has pulled out some fairly amazing technology here in order to contend with distortion that would normally be associated with a lens that uses a 14mm focal length. Typically, a kit zoom lens covers both wide-angle and short telephoto: on the wide end, we see significant barrel (''bloat'') distortion, and on the telephoto end, we see pincushion (''squeeze'') distortion.

This is not the case with the Panasonic 14-45mm. Rather, there is a small amount of barrel distortion at all focal lengths, tapering off to a near distortion-free image at 45mm. Looking at our distortion chart shows results of just 0.1% average barrel distortion between 14mm and 35mm, and around 0.3% in the corners. That's really quite good performance for a zoom lens, especially that it's practically constant across a wide spectrum of the zoom range; this means that if you really do need your straight lines to be straight, you can do so fairly easily in post processing.

At 45mm, distortion approaches zero.

Autofocus Operation
The 14-45mm ƒ/3.5-5.6 focuses very quickly on the G1 body, and locks onto the target well. The focus action is virtually silent. A setting on the G1 allows you to override autofocus results by just turning the focus ring; this setting can also ensure that autofocus results aren't affected by an accidental turn of the focus ring.

Macro
At 0.34x magnification (almost 1:3 reproduction), the Panasonic 14-45mm ƒ/3.5-5.6 offers fairly useful macro capabilities. Minimum close-focusing distance is just under one foot (30cm).

Build Quality and Handling
The 14-45mm ƒ/3.5-5.6 lens is made of a two-tone dense plastic, with a metal lens mount. The micro four thirds format allows the lens to be very compact, and fits the small G1 camera well. At just 60mm long (under 2 1/2 inches) and 195 grams (just under 7 ounces), this is indeed a tiny product.

The lens takes 52mm filters. It isn't adorned with much in the way of instrumentation: lens markings for relevant focal lengths and a switch to control image stabilization are the only features other than the zoom and focus rings. The Mega OIS stabilization has a two-stage setting for ON and OFF.

Manual focus is controlled by a ribbed hard plastic ring about a 1/4-inch wide set, in front of the zoom ring. There are no stops at either the close or infinity end of the focus spectrum. The G1, like other 4/3-mount manufacturers, controls focus electrically, with the lens receiving electrical instructions from the ring, and responding mechanically to focus forward or backward. Manual focus operation is very intuitive on the G1; if enabled via a custom function, the image is magnified to provide high detail for critical focus. During focus the forward lens element doesn't rotate, allowing for painless use of filters.

Zooming through the lens' range of 14-45mm is accomplished with the zoom ring, almost an inch wide and made of a dense rubber. The ring uses sharp, squared ridges that offer good grip. The ring is just stiff enough to prevent any form of zoom creep, but it still very smooth and easy to turn. About seventy degrees of turning will move you through the lens' zoom range. At 45mm, the lens has extended by 1 1/8 inches.

The lens hood provided with the 14-45mm adds about 1 1/2 inches to the overall length of the lens; it's petal-shaped, and attaches with a bayonet-style mount. It's ribbed on the inside to reduce stray light, and reverses to be attached to the lens for storage.

The Mega OIS feature of the lens activates very quickly, and is virtually silent in its operation. We're still in the stages of finalizing our image stabilization test results, but we can say that the lens stabilization is consistent with what we've come to expect from Panasonic. Three modes of image stabilization are offered in the G1: continuous mode, a mode that operates only when the shutter is depressed, and a panning mode that corrects vertical movement only.

Alternatives

It's still early days for the Micro Four Thirds system, so there isn't anything out of the box that counts as an alternative. However, the Four Thirds designers smartly created an adapter to allow regular four-thirds lenses to be mounted, offering backwards-compatibility for G1 users.

Any of these alternative recommendations should be taken with a large grain of salt; who knows what effects to image quality will occur when using the regular 4/3rds - micro-4/3rds adapter.

If you do want to use the adpater to mount Olympus lenses to the G1, you'll need to update your camera with a firmware update provided by Olympus: see the end of this article for the link.

Olympus 14-54mm ƒ/2.8-3.5 Zuiko Digital ~$400
The 14-54mm ƒ/2.8-3.5 is slightly sharper, but shows off a bit more CA. Distortion is handled better on the Olympus lens.

Olympus 14-42mm ƒ/3.5-5.6 ED Zuiko Digital ~$?
Optically, the Panasonic is sharper than this lens, and controls CA better; the Olympus lens controls distortion slightly better. This lens was really only sold with the E-400, E-410 and E-510 body kits, so if you do find a copy it would probably be a used one.

Conclusion
As the first lens to come out of the gate in the Micro Four Thirds system, the 14-45mm ƒ/3.5-5.6 doesn't disappoint, providing more than capable performance in a miniature package. It's not perfect, but its flaws are relatively minor and it complements the G1 camera very well.

A postscript to this review: in our test of the G1, we have our suspicions that Panasonic may be doing post-capture processing to reduce chromatic aberration and distortion, thus improving the performance of the lens. But we won't know for sure until someone comes up with a RAW converter for the G1.

Finally, as noted earlier, Olympus has made available a series of firmware updates to enable Olympus 4/3rds lenses to be compatible with the Panasonic G1. Both the G1 and the relevant lenses must be updated, all of which is done through the camera. If this applies to you, here's the link to Olympus' firmware update site:

Olympus Firmware update for G1 / 4/3rds lenses

Sample Photos

The VFA target should give you a good idea of sharpness in the center and corners, as well as some idea of the extent of barrel or pincushion distortion and chromatic aberration, while the Still Life subject may help in judging contrast and color. We shoot both images using the default JPEG settings and manual white balance of our test bodies, so the images should be quite consistent from lens to lens.

Still Life shot

VFA target

As appropriate, we shoot these with both full-frame and sub-frame bodies, at a range of focal lengths, and at both maximum aperture and ƒ/8. For the ''VFA'' target (the viewfinder accuracy target from Imaging Resource), we also provide sample crops from the center and upper-left corner of each shot, so you can quickly get a sense of relative sharpness, without having to download and inspect the full-res images. To avoid space limitations with the layout of our review pages, indexes to the test shots launch in separate windows.