New system accessories and innovative lenses developed concurrently with the EOS 7
Speedlite 420EX Battery Pack BP-300 EF28-200mm f/3.5-5.6 USM
Continuing from the previous issue, this month's Technical Report provides information on the system accessories and new lenses that have been developed concurrently with the EOS 7.
Photo 1 EOS 7 with Speedlite 420EX	Photo 2 Speedlite 420EX (rear view)
Speedlite 420EX: Overview and characteristics Concept of development Speedlite 420EX (Photo 1) is a shoe-mount flash with E-TTL wireless autoflash developed to best match the requirements of the EOS 7. The purpose of the development is to realize a flash unit "satisfying broader needs with high output, small size, and multiple functions." In the EX series flash system lineup, the 420EX is the successor to the Speedlite 380EX, and has the following improved features. Characteristics [1] High-output autozoom flash with a maximum guide number of 42 The Guide Number of the 420EX is increased to 23-42 (at ISO100 in meters) compared to the 380EX's 21-38. Like the 380EX, the 420EX has a six-position internal autozoom head that couples with lens focal lengths from 24mm to 105mm. The autozoom head is positioned automatically and quickly to suit the lens focal length. The Guide Number at each focal length is shown in Table 1. [2] Compact body With its internal zooming flash head, the volume of flash head is reduced by approximately 30%, resulting in narrowing of the body width by 5mm and the body depth by 4.2mm. Although the height is increased by 9.5mm compared to the 380EX, the overall volume of the unit is decreased by approximately 10%. [3] Compatibility with E-TTL wireless autoflash Like the 380EX, the 420EX is equipped with the following mechanism to support E-TTL wireless autoflash. E-TTL preflash evaluative metering linked to the active focusing point  • Before the main flash is fired for the exposure, the 420EX performs the following series of functions within two milliseconds, based on the flash aperture, which can be set manually or automatically. Fire a weak preflash  • Detect the lighting condition across the entire scene using the 35-zone evaluative metering sensor incorporated in the EOS 7  • After autofocus is determined, instantly analyze and determine whether or not the picture composition has been changed or abnormal reflecting objects exist, as well as whether or not the focusing point and the main subject of the flash exposure coincide Calculate the main flash output optimized for natural rendering of the subject depending upon the specific conditions, and store the value This mechanism has been well accepted as the one that allows users to get natural flash pictures automatically while giving priority to the main subject in the frame. When the 420EX is used with EOS cameras other than the EOS 7, but which are compatible with the E-TTL wireless autoflash system, similar control can be achieved corresponding to the multiple zone evaluative metering system of the specific camera. FE lock Flash Exposure (FE) lock is the flash version of Auto Exposure (AE) lock. With FE lock, the correct flash exposure reading for any part of the subject can be stored. If Custom Function 8-1 of the EOS 7 (C.Fn-8-1) is selected, it is possible to make the FE Lock shooting linked to seven focusing points. High-speed sync (FP Flash) When the flash mode is set to high-speed sync using the switch located on the back of the 420EX, the flash can synchronize with any shutter speed. This is a very powerful function for daylight sync shooting using high shutter speeds. [4] AF-assist beam linked to seven focusing points The 420EX has a built-in AF-assist beam that produces a cross pattern with vertical and horizontal stripes that cover the seven focusing points of the EOS 7. The AF-assist beam is effective from approximately 0.7 ~ 7m at the center focusing point and 0.7~ 5m around the periphery. When the 420EX is mounted on the EOS camera other than the EOS 7, but which supports the E-TTL wireless autoflash and multiple zone evaluative metering systems, the light projection is confined to the horizontal pattern, and is not compatible with the vertical focusing points. [5] Bounce function While the bounce of the 380EX is limited to the vertical direction, the 420EX permits the bounce up to 90 degrees upward, 180 degrees to the left, and 90 degrees to the right. [6] Modeling Flash Since the 420EX is equipped with the modeling flash function similar to that of the 550EX, it is possible to check the flash lighting prior to shooting when the unit is used on a EOS-1V, EOS-3, EOS 7, or EOS D30. [7] Wireless slave setting Using the 420EX as a slave unit, an E-TTL wireless multiple autoflash system can be created together with a master unit (550EX, ST-E2, or MR-14EX) mounted on an EOS camera supporting the E-TTL wireless autoflash system. 420EX and 550EX Speedlites can be set and used together as wireless slave units. [8] Power supply compatible with various size AA batteries Any four size AA batteries (alkaline, Ni-Cd, lithium, or Nickel-hydride) can be used for the power supply of the 420EX. Although the power switch has only two positions, On or Off, the 420EX has a save energy (SE) mechanism that automatically turns the power off when the switch is left on over 90 seconds of non-use. If the SE mode is in effect, pressing the shutter button halfway down cancels the SE mode and turns the 420EX on. These are the major features of the 420EX. Table 1 is a comparison of major specifications of the 420EX and 380EX, while Fig. 1 shows the nomenclature of the 420EX.
Fig. 1 420EX Nomenclature
Table 1 Comparison of the major specifications of 420EX and 380EX Item 420EX 380EX E-TTL autoflash Available Available TTL autoflash Available Available Autozoom range (focal length covered) 24 - 105 24 - 105 Guide No. at normal sync (at ISO 100 in meters) 24mm 23 21 28mm 25 23 35mm 31 28 50mm 34 31 70mm 37 33 105mm 42 38 High-speed sync (FP flash) Available Available Modeling flash Available N/A Manual flash N/A N/A FE lock Available Available FEB N/A N/A Recycling time (sec./size AA alkaline batteries) 0.1 - 7.5 0.1 - 7.5 Flash count (size AA alkaline batteries) 200 - 1400 260 - 1800 Bounce Flash Up (0-90°) Available Available Left (0-180°) Available N/A Right (0-90°) Available N/A Bounce lock Available N/A AF-assist beam Focusing points 7 1 Range at center (m) 0.7 - 7 0.7 - 10 Range at periphery (m) 0.7 - 5 - Wireless slave setting Flash mode E-TTL N/A Slave group ID 3 (A, B, C) N/A No. of channels 4 N/A Power source Four size AA alkaline batteries Four size AA alkaline batteries Dimensions (mm) Width 71.5 75 Height 123 113.5 Depth 99.4 103.5 Weight (g) (excluding batteries) 300 270 Price (Yen, excluding tax) 32,000 27,000 Released Oct. 2000 Sep. 1995
Battery Pack BP-300: Overview and characteristics Overview The Battery Pack BP-300 (see Photo 3) is an external battery pack dedicated to the EOS 7 that enables the camera to be powered by size AA batteries. It has a grip and its own shutter and AE lock buttons for vertical format shots. Characteristics [1] Compatibility with various size AA batteries Four size AA batteries (alkaline, or Ni-Cd) can be used. Table 2 indicates battery life with the BP-300. Please note that size AA lithium batteries cannot be used since their initial voltage is too high, although size AA nickel-hydride batteries can be used without any problem.	Photo 3 EOS 7 with BP-300
Table 2 Battery Life with the BP-300 Battery Type Temperature 0% Flash Use 50% Flash Use 100% Flash Use Size AA alkaline batteries 20°C 115 (125) 30 (34) 15 (17) -20°C 0 (0) 0 (0) 0 (0) Size AA Ni-Cd batteries 20°C 85 (93) 24 (27) 12 (13) -20°C 50 (55) 15 (17) 7 (8)
*The figures above are based on Canon's testing conditions. The numbers in parentheses indicate the number of rolls taken without any use of Eye Control. [2] Compatibility with the camera body's lithium battery By pulling up the spacer (see Fig. 2) located inside the battery compartment, two lithium batteries (CR123A) from the EOS 7 can be installed instead of four size AA batteries. With this arrangement, the BP-300 gives the EOS 7 a vertical grip that is lighter than when the size AA batteries are used.
Fig. 2 BP-300 Nomenclature
[3] Equipped with vertical-grip shutter button [4] Equipped with vertical-grip AE lock button [5] Small and light weight The BP-300 is a compact and lightweight design having a width of 152.4mm, height of 78.5mm and depth of 67.3mm, and weight of 150g. After removing any batteries inside the camera's battery component, the BP-300 can be attached flush to the bottom of the EOS 7 using the camera's tripod socket. [6] Hand strap available The Hand Strap E1 (optional) can be installed to provide a secure grip on the battery pack. The maximum continuous shooting speed of the EOS 7 without the battery pack is approximately 4 frames per second (fps) after in-focus in the One-Shot AF mode, and approximately 3.5 fps in the AI Servo AF mode. When the BP-300 with size AA batteries is mounted on the camera, the speeds are approximately 4 fps after in-focus in One-Shot AF mode, and approximately 3 fps in the AI Servo AF mode. The suggested retail price in Japan is 9,500 yen (excluding tax).
EF28-200mm f/3.5-5.6 USM: Overview and characteristics Overview The EF28-200mm f/3.5-5.8 USM (see Photo 4) is a high magnification zoom lens with a zoom ratio of over 7X. This lens is both light and compact, while zooming all the way from 28mm wide angle to the 200mm telephoto.	Photo 4 EF28-200mm f/3.5-5.6 USM
Characteristics [1] New zoom lens having the zoom ratio of over 7X and covering from 28mm wide angle to 200mm telephoto field With this single lens on the camera, users can enjoy picture taking on various occasions including travel, landscapes, sporting events, portraits and snapshots. [2] Compact design with two aspherical lens elements to obtain high-quality images across the entire zoom range In the optical system comprised of 16 elements in 12 groups, a replica aspherical lens is employed for the fourth element, and a molded glass (GMo) aspherical lens is used for the fourteenth element. With this construction, it produces high-quality images across the entire zoom range while holding the number of lenses elements is kept at a minimum. It also features the five-group design with all five groups moving during zooming. This innovative design makes it possible to hold the overall length of the optical system to a minimum (the linear movement of the front group lens is 50mm) while maintaining the zoom magnification at a high 7x. Thus the lens becomes very compact.
Fig. 3 EF28-200mm f/3.5-5.6 USM Optical Schematic
[3] Minimum focusing distance of 45cm over the entire zoom range Equipped with the inner focusing system, the minimum focusing distance of 45 cm is maintained over the entire zoom range. It also gives close-up shooting with the maximum magnification of 0.28x at the telephoto end. When an extension tube is used along with the lens, as indicated in Table 3, it is possible to obtain the maximum magnification of 0.54x with the EF12 and 1.1x with the EF25.
Table 3 Focusing distance and magnification when used with the EF12 or EF25 Conditions Focusing distance (mm) Working distance (mm) Magnification (x) Picture Field (mm) WIDE TELE WIDE TELE WIDE TELE WIDE TELE EF12 Near distance 175 356 29 160 0.54 0.42 46 x 71 57 x 86 Far distance 193 3456 47 3260 0.43 0.06 58 x 89 374 x 556 EF25 Near distance 164 312 3 101 1.1 0.6 22 x 34 40 x 60 Far distance 170 1807 9 1596 0.94 0.14 26 x 40 169 x 252
[4] Silent, high-speed AF with Micro Ultrasonic Motor (USM) [5] The front of the lens does not rotate while focusing, so operation with circular polarizing filters is enhanced. [6] Only environmentally friendly lead-free glass is used The lens accepts 72mm screw-in filters, the overall diameter is 78.4mm, the overall length varies from 90 to 140mm, and it weighs 500g. In Japan, the suggested retail price of the lens with the carrying case is 72,000 yen (excluding tax). Also available, but separately sold, is the scalloped lens hood, EW-78D. The suggested retail price in Japan is 3,500 yen. [Note] Although the lens does not have the distance scale window, Table 4 provides the depth of field data as a reference.
Warning Since the manual focusing ring on the lens rotates during autofocusing, be sure not to touch it during autofocusing. When focusing manually, always set the switch to the manual focus mode (MF) before rotating the ring. Moreover, when the lens with hood attached is used together with the camera's built-in flash, vignetting may occur. Remove the hood and do not shoot subjects closer than 1 meter. Introduced in this issue are three new products that were developed concurrently with the EOS 7. Please visit a camera store in your neighborhood and check these products as well as the EOS 7.