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
Photo 1 EF-S18-55mm f/3.5-5.6 USM

Concept of development
The EF-S18-55mm f/3.5-5.6 USM (Photo 1) is a standard zoom lens developed exclusively for the EOS Kiss Digital with the following objectives:

Compactness, light weight and high image quality by designing an optical system optimized for the Advanced Photo System C size imaging element dimensions

Wide zoom range (eqv. to 29-88mm in 135-format)

Silent, high-speed AF

Minimizing ghost and flare prevalent in digital photography

New exterior design clearly identifies as the "EF-S" lens


Feature 1: Compact, high performance optical system
The new optical system developed for the EF-S18-55mm f/3.5-5.6 USM is optimized for CMOS sensor of the Advanced Photo System C size equipped to the EOS Kiss Digital. The EOS Kiss Digital adopts a compact main reflex mirror that moves back slightly as it swings up (refer to Technical Report September 2003 issue). Therefore back-focus (distance from the rear of the lens to the focal plane) of the lens can be made shorter than for the other EF lenses.

In addition, the optical system is more compact because the image circle need only cover the image sensor diagonal. In the EF-S18-55mm f/3.5-5.6 USM, these factors all contribute to the optimization of the optical design, resulting in a compact optical system that provides an extended zoom rage as well as improved image quality (see Fig. 1).
* The "S" in "EF-S" comes from "Small image circle."
Fig. 1 Back Focus and Frame Size Comparison
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).

Fig. 2 EF-S18-55mm f/3.5-5.6 USM Optical System
Fig.2 EF-S18-55mm f/3.5-5.6 USM Optical System
Fig. 3 MTF Characteristic Charts of EF-S18-55mm f/3.5-5.6 USM
Thick lines: 10 lines/mm; thin lines: 30 lines/mm. The darker black lines represent the MTF characteristics at maximum aperture; the lighter lines at f/8. The solid lines trace the radial S (sagittal) curve, while the broken lines trace the tangential M (meridional) curve.
Fig. 3 MTF Characteristic Charts of EF-S18-55mm f/3.5-5.6 USM

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
Fig. 4 Lens Mount Structure
New design for "EF-S" lens
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
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.

Fig. 5 EF55-200mm f/4.5-5.6 II USM Optical System
Fig. 5 EF55-200mm f/4.5-5.6 II USM Optical System
Fig. 6 MTF Characteristic Charts of EF55-200mm f/4.5-5.6 II USM
Fig. 6 MTF Characteristic Charts of EF55-200mm f/4.5-5.6 II USM
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
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:
• Extension Tube EF12 II: ø65 x 12.3mm / 66g / 9,500yen (including case, tax not included)
• Extension Tube EF25 II: ø65 x 27.3mm / 95g / 14,500yen (including case, tax not included)
* The Extension Tube EF12/EF25 cannot be attached to the EF-S18-55mm f/3.5-5.6 USM.


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
Focal Length/
Aperture Ratio		 18-55mm f/3.5-5.6 55-200mm f/4.5-5.6
Picture Size 15.1 x 22.7mm 24 x 36mm
Lens Construction 11 elements in 9 groups 13 elements in 13 groups
Angle of View Diagonal 74°20' -27°50' 43°-12°
Vertical 45°30' -15°40' 25°-7°
Horizontal 64°30' -23°20' 36°-10°
Minimum Focusing Distance 0.28m(at all zoom focal lengths) 1.2m(at all zoom focal lengths)
Maximum Magnification/
Field of View		 0.28x
 0.21x
54mm x 81mm 112mm x 166mm
Minimum Aperture f/22-36 f/22-27
(f/22-29 in cameras with
1/3 stop display)
Filter Size ø58mm ø52mm
Gelatin Filter Holder III: Compatible
(hood cannot be used)		 III: Compatible
(max. of 3 hoods can be used)
IV: Compatible
(hood cannot be used)		 IV: Compatible
(max. of 3 hoods can be used)
Maximum Diameter x Length ø68.5 x 66mm ø70.4 x 97.3mm
Weight 190g 310g
Hood EW-60C ET-54
Lens Case LP814 LP1016
Price Only available in
EOS Kiss Digital Kit		 40,000 yen
(including lenscase,
tax not included)



Table 2 Data when used with the Extension Tube EF12 II / EF25 II
EF-S18-55mm f/3.5-5.6 USM
Settings Focusing distance (mm) Working distance (mm) Magnification (x)
WIDE TELE WIDE TELE WIDE TELE
EF12 ll Near distance 135 215 0.4 79 0.81 0.57
Far distance 139 377 8 244 0.66 0.23
EF25 ll Near distance Incompatible 201 — 50 — 0.92
Far distance 265 117 0.51

EF55-200mm f/4.5-5.6 II USM
Settings Focusing distance (mm) Working distance (mm) Magnification (x)
WIDE TELE WIDE TELE WIDE TELE
EF12 ll Near distance 410 1009 245 802 0.26 0.29
Far distance 429 3470 275 3274 0.22 0.06
EF25 ll Near distance 308 885 129 663 0.5 0.38
Far distance 299 1823 131 1612 0.48 0.14