Released as the successor model of the EOS 60D, the EOS 70D is equipped with a new, revolutionary technology, "Dual Pixel CMOS AF." The following is an interview with the development team on the user benefits of the EOS 70D. Here in [Part 1], the Developers share with us the superb basic performance of this new model. (Based on the interview held in August 2013) (Interviewer: Ryosuke Takahashi/ Photos by: Takehiro Kato)

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(Back row, from left)
Shinichiro Yano, Camera Development Center/ Yohei Yamanaka, Camera Development Center/ Hideaki Ohshima, Camera Development Center/ Atsushi Watanabe, Photo Products Group
(Front row, from left)
Kazuhiko Miyahara, Design Center/ Futoshi Hirai, Camera Development Center/ Hiroshi Miyanari, Camera Development Center/ Saori Yasukawa, Photo Products Group

User Friendly AF area selection modes provide new AF shooting experience for all levels

― First of all, please tell me more about the basic concept of the EOS 70D and the target user group.

Yasukawa The EOS 70D is a high-quality digital SLR that is equipped with both an overwhelmingly high level of basic performance as well as an extensive range of advanced features. Besides the users of the EOS 50D and EOS 60D, which are its predecessor models, the EOS 70D is also intended for users who are seeking to upgrade from their current compact digital cameras or entry-level DSLRs.

― Where is the EOS 70D positioned in the EOS series?

Yasukawa The same position as that occupied by the EOS 60D, or, more specifically, between the EOS 700D and the EOS 7D.

― Which functions of the EOS 70D do you think are the main features? How would using these features change the view of the users toward photography?

Yasukawa First and foremost is the Dual Pixel CMOS AF, which has been introduced on the EOS series for the first time. By using this feature, focusing can now be performed equally quickly during Live View shooting as well as viewfinder shooting. Users can also make active use of it for scenes that could not be captured easily using the Live View function in the past. The second point is the significant enhancement in the basic performance. The EOS 70D comes with features such as the DIGIC 5+ image processor, an APS-C size CMOS sensor with a resolution of about 20.2 megapixels, a built-in wireless LAN feature that is available for the first time on APS-C format cameras, as well as the HDR mode and multiple-exposure feature. By making effective use of these features, users will be able to further enhance their expressive ability.

Watanabe In addition to improvements made to the basic shooting functions, we have also reinforced the AF performance of the Live View function on the EOS 70D. Although we have been making stable progress on the Live View function in the past, the introduction of the Dual Pixel CMOS AF has helped to make a giant step forward in the basic EOS concept, which is "Speed, Comfort, Quality." We will talk about the details later, but if I were to describe the feature of the Dual Pixel CMOS AF in short, I would say that it offers "hunting-free AF" even during Live View shooting.

― I see. We will go into the details of the Dual Pixel CMOS AF later. Meanwhile, can you tell me more about the features and performance of the AF sensor used for viewfinder shooting?

Hirai The EOS 70D is built in with a 19-point all cross-type AF sensor, the same sensor that is also employed for the EOS 7D. However, we have made modifications to accommodate the sensor unit into the body of the EOS 70D.

― There are three types of AF area selection modes on the EOS 70D. Is there any special reason for not including the [AF point expansion] and [Spot AF], which are available on the EOS 7D?

Hirai There was debate on this issue when we were determining the specifications of the EOS 70D. The EOS 7D is a higher-end model that works best for genres such as sports and portrait shots. In order to capture the right moments in these scenes, we have included five AF area selection modes on the EOS 7D. The EOS 70D, on the other hand, is also designed for those who are beginners of digital SLR cameras. To enable easier use of the camera, we decided to narrow down the AF area selection modes to the three main types.

― There is a button beside the shutter button. What is it used for?

Yasukawa That is the "AF area selection mode button." Pressing it allows you to select the AF area selection mode, a simpler operation compared to that on the EOS 7D. Also, the currently selected AF area selection mode can be viewed through the viewfinder.

― Are the performance and characteristics of AI Servo AF the same as those of the EOS 7D? Please also describe the details of the advancements made.

Yano The EOS 70D uses AI Servo AF II, which is also employed for the higher-end models. With this function, the EOS 70D is capable of tracking the subject with greater accuracy and stability compared to the EOS 7D.

― Is the basic technology of the Intelligent Viewfinder on the EOS 70D the same as that on the EOS 7D?

Hirai The transparent LCD employed for the viewfinder display makes use of the same technology as that of the EOS 7D, and it can be made opaque by applying a voltage. For shooting at dark locations, a red LED light is illuminated to improve the visibility. Information that is newly added in the viewfinder display includes the AF area selection mode, which has been mentioned earlier. A simpler display of the electronic level compared to the conventional design has also been newly added. The electronic level is a convenient tool for checking the horizontality of the camera while looking through the viewfinder. Of course, you can also choose whether to display or hide it in the menu.

― In what increments does the electronic level measure and display the tilt?

Hirai The electronic level is able to measure tilt in 1° increments. While the tilt is displayed in the rear LCD monitor in 1° increments, one of the three following types of displays is used when it is displayed as an icon in the viewfinder: [Horizontal], [Tilt 1°], or [Tilt 2° or higher]. When displayed using the AF points in the viewfinder, the level is able to indicate tilt in 1° increments up to 6° in the horizontal orientation, and up to 4° in the vertical orientation.

Hirai For the conventional method that makes use of AF points, the electronic level does not function when focusing is in progress. With the EOS 70D, however, we have added a new icon display mode, which allows users to check for camera tilt while focusing.

EOS 70D given the cutting edge technologies developed for the higher-end models

― Is the optical viewfinder newly designed? What is its coverage and magnification?

Hirai Yes, the optical system of the viewfinder adopts a brand new design. While the viewfinder coverage of the EOS 60D was about 96%, we have raised it to about 98% on the EOS 70D. As for the magnification and eyepoint, we have also paid attention to prevent the specs from deteriorating due to the wider coverage. We were therefore able to achieve a magnification of about 0.95x (-1m^-1 with 50mm lens at infinity) and an eyepoint of approximately 22mm (from eyepiece lens center at -1m^-1).

― What were the technical factors that contributed to the enhancement of the viewfinder coverage?

Hirai By changing the pentaprism and making modifications to the eyepiece lens, we succeeded in achieving a coverage of about 98%. No new technologies were employed in this case. We decided to adopt a spec of about 98% upon considering the need to make the camera lighter and more compact, as well as the balance between the viewfinder image quality and the camera size.

― The EOS 70D is the first APS-C format model in the EOS lineup to exceed a resolution of 20 megapixels. Not only so, it also supports continuous shooting up to about 7fps. Please tell me more about the technical background to achieving both a high pixel count and high continuous shooting performance.

Hirai From the viewpoint of mechanical design, it would be impossible to achieve a spec of about 7fps if we had adopted the same technologies as those for the EOS 60D. We were aware of issues such as the large power consumption and the movement of the drive units at the design stage. To overcome these obstacles, we utilized the technologies employed for the EOS 5D Mark III in the design of the components for the EOS 70D so as to enhance the mirror drive efficiency and reduce the burden on the mirror. Based on such a design, we tried to minimize the power consumed while moving the mechanical unit at about 7fps.

― From the electronic device's point of view, what are the factors that contributed most to realizing the spec of about 7fps?

Yamanaka Compared to the DIGIC 4 image processor used on the EOS 60D, the DIGIC 5+ of the EOS 70D is much more powerful in its processing capability. Other factors include the higher read speed of the CMOS sensor as well as the higher speed of processing the corresponding signals by the front-end device. By enhancing the speed of the entire system while ensuring that no bottleneck is created, we were able to achieve a spec of about 7fps.

―  How many channels are used to read from the image sensor?

Miyanari Eight channels. In addition to increasing the number of effective pixels from about 18 megapixels on the EOS 60D to about 20.2 megapixels on the EOS 70D, the continuous shooting speed is now faster too. Coupled with the use of the Dual Pixel CMOS AF, the amount of information read from the image sensor is massive. Nonetheless, we succeeded in achieving this spec by brushing up the existing technologies.

―  What is the durability of the shutter unit? Please also describe the features of the unit.

Hirai The durability of the shutter unit is about 100,000 cycles, the same as that of the EOS 60D. We have also optimized the layout of the gear and cam, thereby reducing the width of the shutter unit by about 5mm. This effort, too, contributed to the more compact size of the camera. Taking into consideration the maximum continuous shooting speed of about 7fps, we have also improved the durability of the different components, such as by changing the material used for the shutter vane.

―  Does the shutter unit employ a two-motor system?

Hirai Yes. The EOS 70D also employs a two-motor system, which makes use of two independent motors for operating the mirror and the shutter separately. The motor used for the shutter is the same as that used on the EOS 60D, but we have enhanced the gear efficiency for it to support the maximum speed of about 7fps. We have also added a silent shooting mode. During normal shooting, the motor is turned in a fixed direction, and the mirror is flipped up by the force of the spring, and flipped down by the driving force of the motor. While this method is suitable for moving the mirror instantaneously, it causes the mirror to generate a hitting sound. In the silent mode, however, the motor turns slowly in the reverse direction, and since the mirror is also flipped up using the drive power of the motor, mirror hitting sound is reduced. Additionally, the mirror is also made to flip down at a slower speed than during normal shooting so as to achieve more silent operation in general.

―  The approach of reversing the motor rotation is also employed on the EOS 100D. Do they share the same technologies?

Hirai The EOS 100D has only one motor, but you can assume that the way of controlling the mirror is basically the same.