LEICA DG Lens Story - The Quest for Changing Photography
LEICA DG VARIO-ELMAR 100-400mm / F4.0-6.3 ASPH. / POWER O.I.S.
1. Development background
A desire to bring the world of ultrazoom to more people.
How would you like to get closer to wild birds, animals and sports action, to reveal the details of distant subjects that elude the naked eye, to just zoom in, fill the viewfinder screen, and take the shot? An ultrazoom lens opens a new world of photographic pleasure. But we also know that the field of vision through the viewfinder is much narrower than you normally see, so framing can be a real challenge. We know you want an ultrazoom that you can easily take with you. Our expert development team wanted to let you experience the delight, amazement, and beauty that only ultrazoom can bring. This desire gave birth to an exciting new lens..
[Technical Notes #1]
Covering the same field of view as the human eye, the Four Thirds standard lens has a focal length of 25 mm.*1 Zoomed to 400mm,*2 the image in the viewfinder is 16 times larger than you can see unaided. At the same time, the area you see in the viewfinder is 256 times smaller. To zero in on such a tiny target area, you need to work on your technique. With a conventional (DSLR) ultrazoom, perseverance is needed to acquire the skills and build the muscles you need to use such a hefty lens.
*1 35mm camera equivalent: 50mm
*2 35mm camera equivalent: 800mm
F5.7, 1/4000 sec, ISO 400
©Daniel J. Cox
2. Development aims
Opening up the world of ultrazoom lenses
An ultrazoom lens comes into its own out of doors. Ideally, all lenses should be compact and lightweight. The longer the focal length, however, the longer the lens has to be. Its outer diameter also increases.
It becomes more challenging as well to ensure optimal image quality by correcting optical aberration*1, and more lens elements are needed to obtain the best performance. Elements with ED lens*2, which is dense and heavy, are required. These elements are of large diameter and inevitably add to the weight and bulk of a lens. Our challenge was to make an ultrazoom lens that you can easily take with you and shoot hand-held. Determined to upset conventional wisdom about ultrazoom lenses, we closely focused on size and weight.
[Technical Notes #2]
For a full-size 35mm format camera body, 400mm lenses are at least 30 cm long and weigh as much as 4 kg. Along with the camera body, tripod, and other essentials, the burden is considerable.
3. Image quality goals
Without compromise. Leica DG lens’s expressive power.
The potential of any interchangeable lens is shaped by its expressive power. In designing this lens, the greatest challenge was to come up with a configuration that was able to deliver in a suitably compact form with superb image quality, corner to corner, right across the frame. To achieve this, the lens has a full-length variable zoom structure that employs 20 elements arranged in 13 groups. In the front group are two UED lenses*2 that capture incoming light from the subject side and ensure excellent imaging performance over the entire zoom range. To minimize chromatic aberration, four ED lenses are placed at key points.
In addition, to achieve consistent high-resolution through the entire range from infinity to close up, at the bottom end of the optical system an ED* aspheric lens focuses light onto the sensor. This means that with a maximum magnification ratio of 0.25 (0.5 in 35mm camera equivalent), you can even shoot macro.
F5.1, 1/2500 sec, ISO 640
©Daniel J. Cox
4. Specification goals
4.1. Eminently portable ultrazoom lens
This lens is designed for camera bodies that conform to the Micro Four Thirds standard. In this system, the image sensors have half the diagonal distance and a quarter of the surface area of sensors in 'full frame' 35mm SLR cameras. When mirrorless technology arrived, the reduction of the flange back distance greatly benefitted fisheye, ultrawide- and wide-angle lens users. Along with wider apertures and a smaller size, lenses with shorter focal lengths soon showed dramatic improvements in performance. While the same benefits did not transfer to telephoto lenses, smaller sensor size (imaging area) favored overall lens size reduction and wider apertures. In designing this ultrazoom, we successfully cut the weight to 985 grams, about a quarter of the weight of a 35 mm format 400mm lens. Along with size reduction, we also achieved the first 800 mm* ultrazoom lens designed for Micro Four Thirds camera bodies — the longest interchangeable telephoto lens currently available for this standard. Since this smaller, lighter lens is so easy to handle, it will naturally be often used outdoors. To let you confidently shoot in challenging conditions we included dust sealing and splash-proofing. Because it is such a long zoom, we added a zoom-ring lock mechanism and a 90° rotating tripod collar for shooting in portrait and landscape orientation. To maximize your mobility and ease of shooting, we did all we could to make this ultrazoom agile.
* 35mm camera equivalent.
4.2. Ultrazoom lens for 4K Photo
From still image capture to videography, mirrorless technology has been applied to a wide range of photographic tools. Evolving as an epoch-making new way to cut special moments from the stream of time, 4K Photo helps you achieve the mission of photography. Wild birds and animals, sports action and other subjects you shoot with a 100–400mm lens are likely to be in motion. Using 4K Photo you are more likely than ever to capture that "decisive moment."
F6.3, 1/2000 sec, ISO 800
©Daniel J. Cox
[Technical Notes #3]
Using a long telephoto lens, it can be hard to target the subject in the viewfinder. With an ultrazoom lens, however, you can zoom in from a wider angle and more easily locate the subject you want to shoot.
5. Unique technologies behind the products
5.1. Anti-shake technology
Effective hand-shake compensation lets you enjoy hand-held shooting that much more. This is especially true with telephoto lenses: the longer the focal length, the easier it is for slight motion to blur the image. The fuzzing effect can also make movies hard to watch. This ultrazoom lens consequently comes with high-performance gyro sensors and ball-bearing rollers for optimal shake correction. These are controlled by Power O.I.S., a highly capable system that detects and corrects both high and low frequency shake.
The lens can also be used on camera bodies with built-in Dual I.S.2 shake correction. As a compensation system that works in tandem inside the camera and in the lens, Dual I.S.2 provides a superior level of shake correction.
5.2. Inner focus and zoom tracking control
This lens uses inner focusing*3 for zoom tracking control. Focus is achieved by moving focusing lens groups inside the lens barrel. A special feature of the ultrazoom lens is the use of a single lens group for focusing. In addition, the actuator used for controlling focus is a quiet linear motor that has excellent starting characteristics and powerful acceleration. This ultrazoom lens embodies a number of exclusive technologies. For example, to make zooming more of a pleasure, we consolidated control technologies that accurately gauge ongoing changes in the zoom and focus positions, and process system data at high speed.
[Tech term]
*1 Optical Aberration
Aberration is a type of lens distortion that occurs when light of different colors is refracted differently by the glass lens elements.This is one reason why lenses often consist of pairs of lenses grouped together. To neutralize the effect of aberration, so that all visible colors focus in the same place, the two lens elements in the pair are made of different kinds of glass, with different optical properties.
*2 UED/ED (Ultra Extra-Low Dispersion) lens
With lenses made of only conventional, general-purpose optical glass, the longer the focal length, or the wider the angle of view, the harder it is to correct for chromatic aberration, so the more likely it is that images will suffer from reduced contrast and color blurring. UED/ED lenses overcome this problem, by inhibiting the kind of chromatic dispersion observed in prisms. They work by effectively correcting for both axial chromatic aberration at the telephoto end and chromatic aberration of magnification at the wide-angle end.
*3 Inner Focus System
Using a stepping motor, focusing is achieved by moving internal lens groups. Because the total weight of the focus lenses greatly affects autofocus speed and the need to move the whole lens assembly is eliminated, inner focus is an essential AF lens technology.