|The first Technical Report of 2004 introduces the EF-S18-55mm
f/3.5-5.6 USM, a standard zoom lens dedicated to the EOS Kiss Digital released
concurrently in September 2003, and the compact, lightweight EF55-200mm f/4.5-5.6
II USM zoom lens.
Also provided is information on the Extension Tubes EF12 II / EF 25 II, close-up accessories redesigned for use with the EF-S18-55mm f/3.5-5.6 USM.
|Compact, lightweight and high image quality standard zoom lens exclusively for the EOS Kiss Digital|
|EF-S18-55mm f/3.5-5.6 USM|
|Photo 1 EF-S18-55mm f/3.5-5.6 USM|
|Fig. 1 Back Focus and Frame Size Comparison|
|Wide zoom range of 29-88mm
A zoom range equivalent to the angle of view of a 29-88mm lens in the 135-format is achieved while minimizing the total lens length and the number of optical elements used. The lens consist of 4 lens groups, all of which move (see Fig. 2). By using a molded plastic (PMo) aspherical element, it provides excellent correction for aberrations that arise during zooming, resulting in superior image quality (see Fig. 3).
Minimum focusing distance of 0.28 meters
The minimum focusing distance of 0.28m through the entire zoom range was achieved by increasing the power of the focusing lens group. It also gives a maximum magnification of 0.28x at 55mm telephoto (54mm x 81mm field of view).
Lens coating optimized for use with digital SLR cameras
The EF-S18-55mm f/3.5-5.6 USM features lens shape and coatings optimized for its use with a digital SLR camera. As a result, the lens successfully realizes both appropriate color balance and minimization of the ghost and flare attributable to surface reflections from the imaging element.
Circular aperture for attractive out-of-focus effects
The lens uses an EMD (electromagnetic diaphragm) with an aperture that remains virtually circular from wide open to about two stops down, providing attractive out-of-focus effects (boke).
Feature 2: Mechanical construction exclusively for the EOS Kiss Digital
Rubber ring to prevent scratching
Because of the short back focus, the rear of the lens protrudes further than other EF lenses. Therefore this lens can only be mounted on the EOS Kiss Digital. (The actual mount interface remains the same as that of other EF lenses.)
A rubber ring is installed on the rear of the lens to prevent damage to the inside of the camera if the user attempts to mount the lens on an EOS SLR camera other than the EOS Kiss Digital (see Fig 4).
|Fig. 4 Lens Mount Structure|
|New design for "EF-S"
To heighten the appeal of the "EF-S" lens as distinct from other EF lenses, the exterior design incorporates several innovations such as a zoom ring with two-tone coloring of black and gray metallic finish, an "EF-S" logo on the fixed lens barrel and a white rectangular lens mounting index.
Feature 3: Silent, high speed AF
The ultra small micro USM II and AF drive control optimized for the EOS Kiss Digital contribute to high speed AF performance.
Feature 4: Environmentally friendly lead-free glasses
In consideration of the environment, the optical system contains only lead-free glasses.
Compact, lightweight zoom lens with high-speed AF and digital compatibility
|EF55-200mm f/4.5-5.6 II USM|
|Photo 2 EF55-200mm f/4.5-5.6 II USM|
|Concept of development
The EF55-200mm f/4.5-5.6 II USM (Photo 2) is a compact and lightweight telephoto zoom lens with a wide zoom range from standard 55mm to telephoto 200mm.
While retaining the optical system and mechanical construction of the EF55-200mm f/4.5-5.6 USM, the EF55-200mm f/4.5-5.6 II USM is a totally new and attractive product, equipped with higher-speed AF, optimized lens coating for digital cameras and complete renovation of exterior appearance.
It was developed under the following concepts:
Higher-speed AF than its predecessors
Minimizing of ghost and flare prevalent in digital photography
Feature 1: Higher-speed AF
Like the EF55-200mm f/4.5-5.6 USM, the EF55-200mm f/4.5-5.6 II USM also has an autofocus system using front focusing and micro USM drive. Moreover, an AF drive pattern that best matches the EOS Kiss Digital, high speed CPU and a new AF algorithm that has been developed for the best AF drive in the existing shooting conditions are incorporated to achieve even faster AF speed than previous models.
Feature 2: Optimized coatings considering use with digital SLR cameras
Although the EF55-200mm f/4.5-5.6 II USM employs the same optical system (see Fig. 5) as the EF55-200mm f/4.5-5.6 USM, it features optimized lens coatings to minimize ghost and flare with digital SLR cameras. Furthermore, the lens provides appropriate color balance for both film and digital cameras.
The effective angle of view is equivalent to a focal length range of 88mm to 320mm in 135 format when the lens is used with EOS cameras that have imaging element dimensions of the Advanced Photo System C size.
|Feature 3: Environmentally
friendly lead-free glasses
As the successor to the EF-55-200mm f/4.5-5.6 USM, giving careful consideration to the environment, the optical system of the EF-55-200mm f/4.5-5.6 II USM contains only lead-free glasses.
|Close-up accessories compatible with EF-S18-55mm f/3.5-5.6 USM|
|Extension Tube EF12 II / EF25 II|
|Photo 3 Extension Tube EF12 II / EF25 II|
|The Extension Tubes EF12 II / EF25 II (Photo 3) are close-up
photography accessories for EF lenses that are mounted on the rear of the lenses.
While inheriting the basic specifications such as tube length from the EF12/EF25,
the EF12 II / EF25 II have a larger inside diameter than previous models so that
it can be attached to the EF-S18-55mm f/3.5-5.6 USM that protrudes at the rear.
Since attachment alignment is different with the EF-S18-55mm f/3.5-5.6 USM than with other EF lenses, the Extension Tubes EF12 II / EF25 II have two different mounting indexes at the front of their body: a red round index for EF lenses and a white square index for the EF-S18-55mm f/3.5-5.6 USM.
Maximum diameter, total length, weight and price of the Extension Tube EF12 II / EF25 II are as follows:
|* The Extension Tube EF12/EF25 cannot be attached to the EF-S18-55mm
This issue of the Technical Report introduces two zoom lenses concurrently released with the EOS Kiss Digital, and accessories for close-up shooting.
Table 1 Major Specifications
EF-S18-55mm f/3.5-5.6 USM
EF55-200mm f/4.5-5.6 II USM