The Panasonic Leica 100-400 offers what Leica cannot offer
The Panasonic LUMIX G 100-400 mm LEICA DG VARIO-ELMAR telephoto zoom lens is probably a sensation that many photographers dream about. With a list price of 1699 euros, it will remain a dream for some. But that price is also an indication of the high quality that we can expect. The designation LEICA DG VARIO-ELMAR indicates that this lens meets high quality requirements. Even so, this is not a copy of a Leica lens, since a similar Leica lens does not exist. This is a lens developed by Panasonic and built in Japan—with the collaboration of designers from Leica. A zoom range of 200-800 mm (equivalent for a 35 mm camera) is exceptional. Combine that with a light (less than 1 kilo!), compact, dust- and splashwater-tight lens body with built-in image stabilization, and you can’t believe your ears. If the image quality also competes with that of much more expensive lenses, then you’ll fall off your chair.
Panasonic LUMIX G 100-400 mm LEICA DG VARIO-ELMAR telephoto zoom? Fantastic!
Build and auto focus
The Panasonic 100-400 mm has a beautiful, matte black finish. With a weight of less than 1 kilo, this is a surprisingly light super-telephoto zoom. Lenses with a similar zoom range (or better said: field of view) are easily one and half (APS-C) or more (full-frame) times heavier. The same applies for the dimensions, as you can see in the illustration below, where the Panasonic Leica 100-400 mm is compared with an 800 mm lens with similar brightness for a camera with a full-frame sensor.
The lens consists of 20 elements in 13 groups and has a number of aspherical and extra low dispersion elements that prevent color separation and loss of contrast. The lens elements are coated to minimize internal reflections (with ghosts and loss of contrast as a result).
The Panasonic 100-400 mm is delivered including a removable tripod base. If you use that, then the button on the lens (see the picture above) can be used to turn the camera from horizontal to vertical, without having to remove the lens from the tripod. There is a lock on the lens with which the lens can be locked to any focal length. With other lenses, that is sometimes only the shortest focal length, for transport purposes. There are also two switches on the lens (AF/MF and image stabilization ON/OFF). On the front of the lens there is an integrated, retractable lens hood that is surprisingly small.
The AF works at 240 fps, and that makes the AF surprisingly fast in sunny conditions. The AF is extremely quiet, so that you have little trouble when making video recordings with noise from the AF motor. As with all super-telephoto zoom lenses that I have reviewed to date, you notice that the limited brightness at the longest focal length is less favorable for the AF speed. And the WYSIWYG advantage of a camera with an electronic viewfinder is a disadvantage in some situations with lenses that have a great bokeh. If you point the lens at a bird that is flying, then with an optical viewfinder you see when the bird enters the frame. If the 100-400 mm is not focused to infinity, then because of the great bokeh, you do not see the bird in the electronic viewfinder. If you want to photograph a fast-moving subject like a flying bird, then the chance of a successful shot becomes smaller. Most readers with no or little experience with extreme telephoto lenses don’t realize how difficult it is to aim at exactly the right spot. It takes time if you’re not very experienced. Action photography with a 400mm micro-43 lens is extremely difficult. 
Smaller and lighter: You get the best shots with the lens that you have with you.
Panasonic makes the comparison with an 800 mm lens for a full-frame SLR camera. With both lenses, you get the same picture in a shot, only the SLR—due to the larger sensor—has less trouble with noise and a better bokeh. We will come back to the other image quality characteristics (sharpness, vignetting, distortion and chromatic aberration) in a moment. There is not only a difference in size, but also a significant difference in weight and price. A bit less spectacular—and probably more obvious—would be a comparison with a 600 mm lens for an SLR with an APS-C sensor. Now the sensor sizes and bokeh are more similar to each other. But the weight and size are still plus points that should not be underestimated.
Panasonic 100-400 mm + Panasonic GX8: 400 mm, f/6.3 1000 ISO, 1/640 sec
The Panasonic 100-400 mm forms a great combination with the Panasonic GX8 (although the G7 and GH4 are more obvious in terms of ergonomics). The combination of a very small field of view, compact dimensions, light weight and effective image stabilization means that you can take pictures by hand of small birds, without soon developing shoulder or back pain, or headaches. You can easily keep working with it for a long time, and the quiet and clear viewfinder image gives you more successful pictures.
Vignetting
You will have little trouble with vignetting. RAW files that you open in Lightroom/Photoshop, or jpg files that are stored in the camera, do not show more than 1 stop of vignetting at any focal length/aperture. The vignetting is the most visible at the shortest focal length. These outstanding results are partly thanks to an automatic correction of vignetting. Uncorrected files show visible vignetting at full aperture. 
Distortion
Distortion is also automatically corrected and is not visibly present at any focal length. If you open RAW files with a converter, so that no automatic lens correction is done, then you see a distortion at all focal lengths of 1% barrel-shaped (Move your mouse over the illustration below.) as is common for many telephoto lenses.
Flare
Because a modern lens currently often consists of more than 10 lens elements, and the sensor reflects much more light than analogue film, the chance of internal reflections has become greater since the arrival of digital photography—certainly for wide-angle lenses and telephoto lenses, where you are dealing with large lens elements. Internal reflections can become visible with bright backlighting in the form of lowered contrast and colored ghosts. Even if the light source is located just outside the frame, flare can occur. Modern lenses are therefore treated with special coatings that prevent flare as much as possible. The Panasonic 100-400 mm has, as additional protection, an integrated, retractable lens hood that is remarkably short in comparison with the lens hoods that you normally find on telephoto lenses. During the test, we had little trouble from flare. The shot shown here—in order to test the sensitivity to flare—is made without using the lens hood. At the top of the frame, a purple ghost is visible. In the shots that are made with the lens hood, no flare or ghosts could be seen. It’s possible that with direct backlighting you might see some. The best lens hood is the lens hood that you actually use.
Sharpness
Panasonic 100-400 mm + Panasonic GX8: 400 mm, f/8 200 ISO, 1/640 sec
Fantastic image quality across the whole zoom range
For the performance of the Panasonic 100-400 mm—to give an impression of the sharpness that we might expect—there were impressively good MTF diagrams shown for the Panasonic 100-400 mm. The MTF diagrams that practically all manufacturers put on their websites are based on calculations, where the lens is focused to infinity. The resolution (MTF50) that we measured with Imatest is high across the whole zoom range, where the difference in sharpness between the center and the corners is remarkably small. The highest center sharpness was reached at full aperture or after stopping down 1 stop. The sharpness decreases slowly as the focal length becomes longer, but even at the longest focal length, the sharpness is still high.
Resolution: Full-frame vs micro-43: By expressing the resolution of lenses on test cameras with different sensor sizes (as in the picture above) in lines per image height (LW/PH), you can compare the sharpness of lenses directly with each other, independent of the sensor size. But then you also have to take into account the image height. With an image ratio of 4:3, you have proportionately more pixels in the height than with an image ratio of 2:3. Direct comparison of the resolution (in LW/PH) measured on a micro-43 camera (width:height = 4:3) with the resolution of a lens measured on an SLR camera (width:height = 2:3) is—if you do not take the image ratio into account—more advantageous for a micro-43 camera (with a relatively taller image than an SLR camera). Should you express the resolution in lines per image width, then that would be more favorable for an SLR, with its wider image format. In order to still make it possible to do a fair comparison, we use an image ratio of 2:3 for the calculation of the scores for resolution on micro-43 cameras as well on CameraStuffReview.
Image stabilization
Very effective image stabilization!
We test the image stabilization by taking a couple hundred pictures with and without image stabilization at the longest focal length and measuring the sharpness of the shots with Imatest. Even at a shutter time of 1/1000 of a second, shots are sharper if you use image stabilization. Great performance from Panasonic.
Video: 4K video & full-HD with Extra Teleconversion
The step from image stabilization to video is obvious: with video, you see every vibration and with super-telephoto zoom, those vibrations are enormously amplified. Even a heavy tripod is no guarantee of great shots if you use a very long focal length.
The Full-HD recording below is made with the Panasonic GH4 with V-log L and Extra Tele Conversion, without a tripod in a bird-watching hut on a sack of beans. With Extra Tele conversion, only the center of the sensor is used, so that you get an extra crop factor without a reduction in image quality. That is ideal for taking nature shots and can practically only be found on Panasonic cameras. In this case, it delivers a field of view that corresponds with a 2000 mm lens on a camera with a full-frame sensor. 50p All-intra (compression method where the individual frames are compressed instead of between images, so that you can use every frame as a photo) and 200 Mbit/sec. That makes you want more.
Bokeh
Nine rounded lamellae give the aperture a round shape, for a beautiful bokeh. The longer the focal length, the more you can play with background blur. Take a look at the bokeh ball at the top left in this practice shot. A photographer with an SLR camera and a full-frame sensor would have been proud of that. The bokeh is very nice for a micro-43 lens, but it is not yet perfect. The shot here shows that the bokeh rings often have an extra edge.
Close-up photography
Panasonic 100-400 mm + Panasonic GX8: 364 mm, f/6.1 1600 ISO, 1/640 sec
Click on the illustration above for a compressed version in full resolution.
A shortest focal distance of 130 cm for a lens with the same field of view as an 800 mm lens on a camera with a full-frame sensor is unique. That ensures that you will get more successful close-up shots of subjects that fly away. If you tried that with a macro lens, practically always with a focal length under 200 mm (FF equivalent), then the chance of a failed photo is much greater.
Panasonic 100-300 mm vs Panasonic 100-400 mm (Le roi est mort. Vive le roi!)
Panasonic 100-300 mm delivers beautiful pictures.
Panasonic Leica 100-400 mm, fantastically beautiful shots.
Until recently, if you wanted to have a compact micro-43 super-telephoto zoom lens, then the Panasonic 100-300 mm was the only choice. With a shop price of around 500 euros, the 100-300 mm offers a lot of value for the money, but for both build and image quality, the Panasonic 100-300 mm has to acknowledge its superior in the new Panasonic 100-400 mm. In my eyes, the additional price of 1000 euros is worth the effort of having to scrape together some extra savings. First of all, the 100-400 mm is visibly sharper at the longest focal lengths, while the longest focal length is also 400 mm instead of 300 mm. For both video and photography with a tripod, the built-in image stabilization of the 100-400 mm significantly increases the chance that you come home with successful (video) shots if you use a longer focal length. For video recordings with very long focal lengths, you see the smallest vibration, even if you work from a tripod. Then optical image stabilization is a better and time-saving option. Software image stabilization for video (especially with 4K) eats up a great deal of time. It is especially for the longest focal length that you buy a super-telephoto. The zoom ring of the 100-400 mm will not be bothered as easily by “creeping” (the focal length changing when you hold the lens vertically). Extra sealing against dust and splashwater is an important plus point for the nature photographer who does not only work in nice weather. In short, you get what you pay for.
Conclusion Panasonic Leica 100-400 mm with Panasonic GX8/GH4
Pros
- Fantastic image quality: best super-telephoto zoom for micro-43
- Very compact: easy to take along
- Can be used without a tripod thanks to image stabilization and low weight (less than a kilo!)
- Extra-well sealed against dust and splashwater
- Very well suited for close-ups, thanks to a shortest focal length of 130 cm
- Integrated, retractable lens hood
- Handy tripod collar
Cons
- Price matches the quality
- 400mm f/6.3 is less well suited to action photography
TL/DR (Too long, didn’t read): Panasonic Leica 100-400 mm is a super-telephoto zoom, for which there aren’t enough superlatives
With the arrival of the Panasonic 100-400 mm, the lens selection of compact and high-quality Panasonic lenses is practically complete. With the Panasonic 7-14 mm f/4, Panasonic 12-35 mm f/2.8, Panasonic 35-100 mm f/2.8 and the Panasonic 100-400 mm in a photo bag, you are armed to the teeth without having to lose an arm and a leg. If you are accustomed to an SLR with a 24-70 mm f/2.8 and a 70-200 mm f/2.8, then that combination is more expensive, heavier and about the same size as a Panasonic G7 or GX8 with all four Panasonic lenses. The image quality of micro-43 is surprisingly high. The resolution (in lp/mm) of the Panasonic 100-400 mm is so high that a 24-megapixel camera with a larger sensor takes pictures that aren’t any sharper. You will not be bothered by vignetting and distortion. Thanks to the built-in image stabilization, you have a quiet viewfinder image when you shoot by hand, are less likely to get a motion-blurred shot in low light and get quiet video recordings. The robust construction and the extra sealing against dust and splashwater make this super-telephoto zoom perfectly suited for use under the most extreme conditions. Micro-43 users had to wait a long time for this lens, but it is worth the wait. This is an absolute winner.
