Panasonic Lumix G Vario 100-300 mm for Micro 4/3
The Micro 4/3 format has been around since 2008 and semi-pro Micro 4/3 bodies since 2010 (I am thinking specifically about the Olympus OM-D E-M5 and Panasonic GH2, GH3, G5 and G6). According to Mirrorless Camera Native Lenses, 31 native Micro 4/3 lens models are available from several manufacturers, and according to the MirrorlessDB site as many as 59 (but this list includes several planned or prototype-only models). At the time of writing, the actual number of available lens models might be around 40. This number of lens models is not quite comparable with the choices available to Nikon and Canon DSLR users, but certainly exceeds the number of lenses available for minor DSLR brands like Pentax. However, when it comes to long telephoto lenses suitable for wildlife and bird photography, the choices for Micro 4/3 are still very restricted.
For these applications, as well as sports and events photography, on Micro 4/3 I regard a fast and precise autofocus (AF) as an essential requirement, and a focal length of 300 mm as an absolute minimum (although 400-500 mm is far more useful). There are a few mirror super-telephoto lenses in native Micro 4/3 mounts, which I do not regard as a viable choice because of the lack of AF, rather low image quality and doughnut-shaped bokeh. Likewise, third-party telephoto lenses for other cameras can be mounted on Micro 4/3 adapters but, with the exception of prototype adapters for Canon EOS lenses, only provide manual focus and manual aperture. Adapters for using 4/3 lenses on Micro 4/3 bodies with automatic aperture and AF do exist, but the few "real" telephoto and zoom telephoto lenses available for the 4/3 format, mainly by Olympus and Sigma, are known to provide poor AF performance on Micro 4/3 cameras. In conclusion, there are at the time of writing just two native AF Micro 4/3 lenses reaching 300 mm:
Both lenses are built with the materials and "looks" typical of amateur-level zoom lenses. The barrels are made of plastic and grow substantially in length when zooming. Neither the focus nor zoom rings have the smoothness expected of semi-pro lenses, and some "wobble" of the zoomed-out front barrel is clearly perceptible. The fully open aperture quickly reduces to an effective f/5.6 when zooming away from the lowest focal lengths. Neither lens has a tripod shoe. There is a clear need for faster, better-built lenses and for longer focal lengths before the Micro 4/3 system can become appealing for sports, events, nature and wildlife photography. Nonetheless, these are the only currently available alternatives. On the plus side, both lenses are much lighter and smaller than more serious gear I used to carry around (mainly the Tamron 300 mm f/2.8, Sigma 100-300 f/4 and Sigma 50-500 f/4-6.3).
My choice fell on the Panasonic 100-300, because its price is substantially lower than the Olympus 75-300 while the image quality at 300 mm, according to online reviews, is quite similar. The shorter minimum focal length of the Olympus lens was not a relevant factor for me, because there are faster and far better Micro 4/3 lenses of 60-100 mm focal lengths. In actual photography, I seldom use this lens at less than 250 mm, so the high end of the range of focal lengths is the only one relevant to me. The Panasonic 100-300 provides image stabilization, which is very useful on Panasonic bodies but irrelevant on Olympus bodies (which provide in-body image stabilization anyway).
The Panasonic 100-300 weighs 550 g including lens shade, and is 126 mm long when zoomed at 100 mm. It becomes 185 mm long (226 mm with lens shade) when zoomed at 300 mm. All length measurements are from the extreme front of the lens barrel to the mounting flange. The center of mass is located near the front of the zoom ring at 70 mm and at the extreme front of the zoom ring at 300 mm.
The zoom ring is covered in sculptured rubber and provides a solid grip. As typical of rubber surfaces, it also tends to collect dirt. The focusing ring is much narrower and has a smaller diameter. It is made of sculptured plastic, easier to keep clean but offering a less secure grip.
Zooming the whole range requites a rotation of approximately 90° of the zoom ring. The focusing ring is not mechanically coupled to the focusing helicoid, and manual focusing is by wire. There is no focusing or DOF scale, and the minimum focus distance is 1.5 m at all focal lengths. Focus can be manually retouched by turning the focusing ring at any time, and there is no manual focus/AF switch. There is an on-off switch for image stabilization on the left side of the lens, near the rear of the barrel.
The front filter mount is 67 mm and made of plastic. It does not rotate when zooming or focusing. The front lens element is quite a bit narrower than the filter mount, and there is no risk of vignetting even when using multiple stacked filters.
The optical scheme is complex, with 17 elements in 12 groups. One element uses ED glass.
A 300 mm lens on Micro 4/3 gives the same field of view as a 600 mm on full frame or a 450 mm of APS-C cameras. Therefore, a 300 mm lens on Micro 4/3 should be regarded as a super-telephoto lens. A lens of this type cannot be tested in the same way as a lens of shorter focal length: on distant subjects, the performance of a super-telephoto lens is strongly affected by atmospheric haze, pollution and turbulence, to a much higher extent than a shorter lens. Thus, test pictures of a building located several hundreds of m away, which seem to be a common subject for this type of test, are unsuitable to evaluate image quality. With close-up subjects, on the other hand, a super-telephoto lens may be forced to operate outside its optimal focusing range for best image quality (which typically is more restricted than the focusing range provided by the lens). An indoors subject located 7 m from the camera (conveniently allowed by my living room) is a good compromise between these factors, removes atmospheric degradation and is representative of the typical camera-to-subject distance encountered in small-bird photography.
In practice, at 300 mm and with image stabilization turned on, one should not use exposure times longer than 1/100 s. At 1/60 s, failed images because of camera movement become quite common. It should also be remembered that image stabilization cannot compensate for movement of the subject, so a shorter time than 1/100 s may be required by moving subjects like birds cleansing their feathers or walking on the ground. Tracking birds in flight is a big problem for the AF of any current Micro 4/3 camera, regardless of exposure time. Micro 4/3 cameras are generally hopeless in this respect, unless the bird is flying almost perpendicularly to the lens axis. Regardless of this problem, 1/500 s may be a reasonable exposure time to guarantee steady images with this subject type, or 1/250 s if it is really undesirable to push the ISO any higher.
The upper half of the above test images were shot at 300 mm, which is the only focal length I am really interested in, and 200 ISO. I set the lens aperture at f/5.6 and f/8, which based on theoretical considerations are the optimal values for diffraction just below the visible threshold with Micro 4/3 cameras. The results at the two apertures were not too different but f/8 is better and the natural choice for this lens. Therefore, I am showing only the f/8 results. Autofocus was used, with the autofocus area set to the portion of interest of the subject. All settings remained the same during the test, and no post-processing was carried out.
The camera was mounted on a tripod via the camera's tripod attachment and placed at a distance of 5 m from the subject. The subject was illuminated by a wireless TTL flash (Metz 58 AF-2) in slave mode, triggered by the Olympus FL-LM2 flash in commander mode mounted on the camera, to eliminate any degradation caused by camera vibration and movement. The flash was mounted on a second tripod and placed approximately 2m from the subject. The test chart is the finest square-wave portion of the test pattern from normankoren.com and printed at a width of 285 mm on an office laser printer. Because of limitations intrinsic to this printer, this method produces lines of uneven widths in this area of the test pattern. This is a genuine feature present on the printout and not an artifact produced by the camera or post-processing.
The main problem with the Panasonic 100-300 on an Olympus camera is that the lateral chromatic aberration is modest but visible, and can reach about 1-2 pixels in the image corners. Current Olympus Micro 4/3 cameras do not automatically correct this aberration. However, post-processing (e.g. with Adobe Lightroom) completely removes this aberration. Contrast is also a bit low, but well within the limits that can be corrected with a moderate amount of post-processing.
As a comparison, I repeated the same test with a Tamron 300 mm f/2.8, which is the sharpest lens I own at this focal length. This lens was attached to the OM-D E-M5 via a Nikon F to Micro 4/3 Metabones adapter and used in manual focus and manual aperture mode. The live view image at maximum magnification was used for precision focusing at f/2.8 before closing the aperture to f/8. A direct comparison of the images shows that the focal length of the Tamron 300 is slightly higher than the Panasonic 100-300 zoomed at 300 mm. However, the difference is less than 10% in linear image magnification, and within the limits commonly accepted in the specifications of zoom lenses of long focal lengths. Contrast is also higher in the Tamron lens.
The difference in image quality from the Tamron 300 mm is obvious in the test images, and reflects the difference in class and price between these two lenses. In particular, note that the Tamron 300 is capable of resolving the raster pattern produced by a 600 dpi laser printer (in the gray area at the right of the lines pattern) at the distance of 7 m. Nonetheless, the resolution, color and contrast in the test images of the Panasonic 100-300 are acceptable across the whole frame for most applications (especially if a judicious post-processing is applied), and this lens can resolve even the finest of the vertical line pairs of the test pattern (but not the printer's raster pattern). Image quality with the Panasonic lens is significantly better than I used to get with older consumer-grade zooms, including the Nikon Nikkor AF 70-300 mm f/4-5.6 G (this is the non-ED version), Tamron Aspherical LD Macro 28-300 mm f/3.5-6.3, and Sigma Apo Macro 70-300 f/4-5.6 D. Among the last three lenses, the Nikon one is the best and the closest in performance (on APS-C cameras) to the Panasonic 100-300 on Micro 4/3 cameras, but the Panasonic appears to be somewhat better. As a whole, the Panasonic 100-300 is not exceptionally good but very usable, and certainly worth its price.
Both longer focal lengths and faster apertures would of course be desirable. A 300 mm f/4 and a 450 mm or 500 mm f/5.6 (with AF and refractor, not mirror optics) are sorely lacking among the lenses for Micro 4/3 cameras. However, as long as no such lens is available, or in situations where a higher weight and size would be a problem, the Panasonic 100-300 remains a good alternative.
The lens shade of the Panasonic 100-300 is not so deep for a 300 mm. Since the minimum focal length is 100 mm, the lens shade is designed for this focal length, and therefore it is quite a bit too wide and short for longer focal lengths. Therefore, in sunny conditions, and especially in back-lighting, using a longer lens shade is likely to help increase contrast and reduce the risk of flare. The simplest way of temporarily doing this is by wrapping a matte black thin cardboard sheet or drawing paper sheet around the plastic lens shade, in order to approximately double its length. The cardboard sheet can be held in place with a rubber band.
Chimping (i.e., watching the live view image on the rear LCD screen while holding the camera some distance in front of one's face) with a hand-held Panasonic 100-300 feels rather clumsy. This posture forces an inherent strain on the arms and after a short time may result in increased muscle tremor. It is much better to use the viewfinder, which allows physical contact between the camera and the face of the photographer and provides an additional steadying point for the camera. Use of the viewfinder also allows the arms to be more folded and less likely to suffer from muscle fatigue than when chimping.
A common problem with hand-holding a super telephoto lens in the field is finding and framing the subject. Since the field of view is quite narrow, the camera must be reoriented with small movements by trial and error, until the subject is located. With birds in flight this is especially difficult, since the sky often has no reference points except the bird itself, and the available time is limited to just a few seconds. The method that works best for me is looking at the subject with both eyes open, then lifting the camera viewfinder to the right eye (without closing the left eye or loosing sight of the subject with this eye) and placing the subject in the viewfinder by making small camera movements. The left eye must continue to follow the subject, or you will find yourself trying to center the viewfinder on a portion of sky that the bird has already left. This requires a kind of "split-mind" approach in which the photographer remains simultaneously aware of what is seen by the naked left eye and by the right eye through the viewfinder, but with practice it seems to work for most people. Some people find it easier to locate the subject with the lens zoomed to the lowest focal length, and afterwards to zoom in to the desired length while holding the subject centered in the frame. Image stabilization helps to keep the camera trained on a moving subject, so I prefer to turn this feature permanently on (as opposed to on only during the exposure).
These problems are not specific to the Panasonic 100-300 or Micro 4/3 cameras, but you should be aware of them, especially if hand-holding a super-telephoto lens for the first time. There is nothing "natural" about using these lenses - it is an art that must be learned by doing it for a long time. As a consolation, with the Panasonic 100-300 you don't need to start your training by building up your muscles in a gym, which is often necessary to handle larger and heavier lenses and cameras.
A major fault of both the Panasonic 100-300 and the Olympus 75-300 is the lack of a lens collar and tripod shoe. The Panasonic 100-300, once zoomed to 300 mm, is rather front-heavy and unbalanced. The zoom ring, which is the natural handhold for this lens, is located a little too far back to allow a balanced grip. The light weight of this lens also invites waving it around erratically. On the Olympus OM-D MD-5, it is practically obligatory to use the HLD-6 battery grip (or at least the top half of the grip) to hold the camera body securely. Holding the camera body with normal-sized hands is a common problem with Olympus Micro 4/3 cameras. Panasonic builds a better grip into the body of their current G and GH cameras (albeit not the GX series).
The Panasonic 100-300 is very unbalanced when the camera body is directly attached to a tripod head. The lens attachment of the camera body and the tripod head are forced to bear the whole off-center weight of the lens. This results in a detectable amount of strain, flexibility and sagging, albeit probably not dangerous to the integrity of a solidly built camera like the Olympus OM-D MD-5.
There is a solution to the lack of a built-in tripod shoe for these lenses, and it does not involve the heavy and clumsy-looking long lens supports made, e.g. by Manfrotto and Really Right Stuff (which are meant for much heavier lenses): Rösch Feinmechanik makes lightweight metal tripod shoes for both models of zoom lenses.
The model for the Olympus 75-300 is a rather odd-looking affair with two very thin rings supporting the fixed portion of the lens barrel at either end. This is a design compromise dictated by the lack of large fixed barrel surfaces suitable for attaching a more conventional tripod shoe. The Olympus 75-300 looks superficially similar to the Panasonic 100-300 in apparently having a cylindrical portion of "naked" (i.e., non-sculptured) barrel at the rear of the sculptured zoom ring, but in the Olympus lens this portion of the barrel is acctually a part of the zoom ring and must be free to rotate. This specialized tripod shoe does not allow the lens shade to be reversed onto the lens for storage. A further problem is that attaching and removing the tripod shoe requires the disassembly of the shoe with a screwdriver, which makes this operation impractical in the field (where the four small screws are easily lost). On the other hand, the Olympus lens shoe attaches to the lens at two widely separate points and therefore it is less likely to apply a mechanical stress to its plastic barrel.
I have been informed by Rösch Feinmechanik that they no longer manufacture the tripod shoe for the Olympus 75-300, due to concerns about its functionality. Olympus recently announced their plans to produce an unspecified "super-telephoto" lens for the Micro 4/3 format, which hopefully will be of a high optical quality and will have a built-in tripod shoe.
The tripod shoe for the Panasonic 100-300 weighs 87 g, is a conventional lens collar design made of machined and black-anodized aluminium alloy and looks stronger and more reliable than its Olympus counterpart. It feels very lightweight and attaches around the rear of the lens barrel by a thin ring tightened with a sufficiently large thumbscrew. The camera can be rotated between landscape and portrait orientation, and the On/Off IS switch holds the collar in place. The collar must be mounted onto the lens rotated at a specific position, shown in the instructions sheet.
Two windows are available in the lens collar for accessing the image stabilization switch of the lens with the camera in either orientation. The lens collar attaches to a plastic portion of the lens barrel and therefore the attachment cannot be as rigid and tight as a proper tripod collar designed as part of the lens. However, it is still very useful to reduce uncontrolled movements and to balance the lens quite well when attached to a tripod. In practical use, the Arca-compatible plate built into the bottom of the tripod shoe is very useful, and a nice addition not shown in the pictures on the Rosch web site. The plate does not have end-stop screws, but this is not a major problem. One such screw could be added near the front of the bottom surface. The rear screw that holds the plate attached to the collar could be replaced with a slightly longer flat-head screw and a few washers, and function as a rear stop screw.
In my opinion, this Rösch Feinmechanik tripod shoe is an important reasons to prefer the Panasonic 100-300 over the Olympus 75-300. There is a minor compatibility problem between this tripod shoe and the HLD-6 hand grip for the E-M5, but this should not discourage you from using the Rösch Feinmechanik tripod shoe with this lens.
Other reviews of the Panasonic 100-300
This lens was introduced in 2010, and therefore plenty of reviews of this lens are available, including the following:
The Panasonic 100-300 is one of only two currently available, relatively cheap, lightweight and small native Micro 4/3 lenses that reach 300 mm and provide automatic aperture and AF. Image quality is not exceptional but acceptable, and the usefulness of the lens is greatly enhanced by a third-party tripod shoe marketed by Rösch Feinmechanik. This lens is well worth its price. However, the need remains for native Micro 4/3 lenses of longer focal lengths, faster apertures and semi-professional build.