The EOS 100D is the world's most compact and lightweight digital SLR camera that is equipped with an APS-C size sensor. In this following interview, the development team shares with us stories behind the development scene. Here in [Part 1], behind the scene stories of reducing the size of main components are shared with us. (Based on the interview held in April 2013) （Interviewer: Ryosuke Takahashi/ Photos of interviewees: Takehiro Kato）

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(Back row, from left)
Wataru Yokota, Photo Products Group/ Takashi Watanabe, Camera Development Center/ Tatsuhiro Ohnaka, Photo Products Group/ Masahiro Kobayashi, Photo Products Group/ Hironori Oishi, Design Center
(Front row, from left)
Keisuke Kudo, Camera Development Center/ Tomoaki Tanaka, Camera Development Center/ Masanori Sakai, Camera Development Center/ Hiroaki Nashizawa, Camera Development Center

What is the concept of the EOS 100D?

― With the release of the EOS 700D and the EOS 100D in March 2013, the EOS series now offers a more extensive lineup of models for entry-level users. Can you tell us where the EOS 100D stands in the EOS series?

Kobayashi　The EOS 100D is a new line that we have introduced for entry-level users, which can be characterized by its small size and light weight. While many users tend to shy away from digital SLR cameras because of the "bulky and heavy" body, we hope that the EOS 100D can serve as a gateway for them to enter the world of DSLRs.

Ohnaka Currently, the EOS 1100D is the most introductory model in the EOS series for entry-level users. The EOS 700D and EOS 100D, though both entry-level models too, are positioned on the higher end compared to the EOS 1100D. Both the EOS 700D and EOS 100D are designed for everyday use by families, young users who are not in possession of a digital SLR camera, as well as female users. By offering multiple options, we hope the users can choose one that suits them best according to the aspect they place importance on when looking at the performance of the camera.

― Canon has released the mirrorless EOS M, which also places emphasis on the size and weight. How is the EOS 100D different from the EOS M?

Kobayashi While they both adopt a compact and lightweight design, the EOS 100D has the advantages that only DSLRs equipped with a main mirror and viewfinder can offer. We developed the EOS 100D after giving consideration to the balance between a compact and lightweight design and our users' desire to capture the right moment.

― That was very well explained. I can see that the EOS 700D and EOS 100D share many common features with the EOS 650D. What are the advancements made on the new models?

Ohnaka First of all, we have made improvements to the Creative filter function. When you capture a shot, you can use the touch screen to select a Creative filter effect on the Live View screen, and check the effect in real time. The second point is the lens. We have changed the kit lens for the EOS 700D and EOS 100D to a new lens that is built in with a stepping motor (STM). Thirdly is the Mode Dial. Besides being able to rotate beyond 360°, we have also added new SCN (Special scene) modes, which include HDR Backlight Control, Night Portrait, and Handheld Night Scene. These are some efforts to make it easier for users to capture charming shots of relatively challenging scenes, such as under backlight or at night.

― The EOS 100D does not come with a Vari-angle LCD monitor. What is the main reason for excluding it?

Kobayashi The Vari-angle LCD monitor was very well-received by users of models such as the EOS 650D. However, our ultimate priority in the development of the EOS 100D was the world's smallest and lightest camera, which is why we decided to exclude the Vari-angle LCD monitor.

― Both the EOS 700D and the EOS 100D do not support the Wi-Fi function. Is there a specific reason for this?

Kobayashi Yes. We omitted the Wi-Fi function for the same reason we excluded the Vari-angle LCD monitor. However, Canon sees the Wi-Fi function as an important feature, so it is likely that it will be included in our future entry-level models.

― One distinct difference between the EOS 700D and the EOS 100D is the continuous shooting speed. Can you tell us the differences in their mechanism?

Sakai The motor used to drive the shutter is different. We adopted a smaller motor for the EOS 100D, so we set the continuous shooting speed at about 4 shots per second. Meanwhile, the EOS 700D adopts the same motor as the EOS 650D, which supports continuous shooting at a speed of approximately 5 shots per second.

― For the image sensors used for the EOS 700D and the EOS 100D, can I say that their basic performance is the same except for the area of the image plane AF?

Nashizawa They are basically the same. In strict terms, however, the pixel count of the AF sensors that are embedded in the image sensor is different, and this contributes to a difference in the RAW data before an image is developed. That being said, you can no longer tell such a difference after the images are processed, so you can say that their performance is effectively identical.

Repeated efforts to achieve a compact design

― Can you describe the technical background that led to the realization of the world's smallest and lightest design for the EOS 100D?

Sakai First and foremost is the efforts to adjust the layout of the components that are built into the camera. Each of them was mounted with the space between them slightly reduced. Another contributing factor is the smaller shutter unit. On the EOS 100D, we have adopted a newly-developed shutter unit, which combines the use of an electronic and a mechanical shutter to perform exposure. Doing so allows us to produce a slimmer shutter unit, while at the same time helps to reduce the height of the camera.

― Were changes made to the conventional CMOS sensor in order to achieve a more compact design?

Sakai In the past, the terminals used to protrude from the perimeter of the CMOS sensor, but they have been moved to the rear of the package on the EOS 100D. With the height and thickness of the terminals reduced, we were able to realize a smaller CMOS sensor unit design.

― Is this technology also adopted by other models?

Sakai No. This is a new technology that is also not found on the EOS 1100D. Miniaturization of the main board is possible when the CMOS sensor unit is downsized, and this is an indispensable technology for realizing a more compact design. Also, the size of the main board is reduced by increasing the board density. Other finer details include omission of the battery grip from the EOS 100D at the design phase. Otherwise, we would inevitably have to move the SD card slot to the side of the body, which in turn imposes limits on the miniaturization process, as the area of the card slot and the width of the slot cover need to be taken into consideration. By adopting a design without a battery grip, we were therefore able to place the SD card slot inside the battery compartment.

― I see. That was very well thought out.

Tanaka Another effort to downsize the body is the use of the compact LP-E12 battery, which is also employed for the EOS M. This decision resulted in a battery capacity that is about 20% lower than that of the EOS 700D, but the size of the battery is also smaller by about 30%. Also, to avoid reducing the maximum number of shots on the EOS 100D as much as possible, we re-examined aspects such as the power circuit to achieve a power-saving design.

Sakai To add on, the Self Cleaning Sensor Unit has also been made slimmer. Doing so allows us to shift the position of the main mirror to the rear end of the camera, and is therefore another effective way to reduce the height of the camera.

― Silent shooting modes are available on the EOS 100D. What is the mechanism that makes silent operation possible?

Sakai On the past entry-level models, shutter charge was performed by the motor's movement in the forward direction, while the reverse movement was used to pop up the flash. On the EOS 100D, the reverse movement of the motor is also utilized to drive the shutter unit, and a different drive source is employed to pop up the flash. With the shutter unit now also driven by the reverse movement, there is no need to pass through the area in the cam mechanism that generates the loudest noise.

― So the key point here is the cam movement and control of the motor's rotational direction, am I right?

Sakai Yes, you are correct. The shutter movement during silent shooting is identical to the mirror movement of the EOS 6D, which comes with a dual motor system. The technical challenge, therefore, lies in reproducing this movement with a single motor.

― Is there any difference in AF speed between the conventional Hybrid CMOS AF and the Hybrid CMOS AF II of the EOS 100D?

Kudo By making improvements to the AF drive control, the AF speed became faster than that of the conventional models. Also, as the faster speed is not attributable to the Hybrid CMOS AF II sensor, the same approach may be adopted to enhance the speed of Hybrid CMOS AF sensors in future. How fast the speed increases varies with the lens used, shooting condition, and condition of the subject. For the following conditions of measurement, AF speed increases by about 1.3 times at the center, and about 1.6 times at the peripheral areas (measurement results are relative to that of the EOS 650D; lens used: EF-S18-135mm f/3.5-5.6 IS STM; focal length: 135mm; focus start position: infinity; focusing distance: approx.. 0.5m to 4m).

― My next question is about the viewfinder. Despite the more compact design of the body, the viewfinder magnification is higher. Can you tell us how this spec was made possible?

Sakai The reason is actually very simple. Since the camera body has a slimmer design, we were able to place the eyepiece unit further to the front compared to other models. Doing so shortens the distance to the focusing screen, which explains why the viewfinder magnification is higher. Conversely, if we had included a Vari-angle LCD monitor, the thicker camera body is likely to lead to a deterioration in the viewfinder magnification due to the longer distance to the focusing screen.

― In other words, the magnification increased simply because you are viewing from a closer distance, is that correct?

Sakai Yes, exactly. The logic behind is very straightforward. Also, we devised ways to adjust the layout of the AE sensor so that it can be built into the EOS 100D without being bent. Doing so reduces the height of the unit, as well as the overall height of the camera body.