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EOS 80D Interview with Developers (Part 2): Optical Viewfinder & Metering Sensor

The EOS 80D boasts of many technological advancements. In part 2 of this interview series which conveys the passion of the developers, we asked them about advantages offered by the different technologies such as the 100% optical viewfinder coverage realized amid the EOS 80D’s mid-sized body, and the new metering sensor. (Interviewer: Ryosuke Takahashi    Group photo: Takehiro Kato)

(Back row from left) Kohei Furuya (ICP R&D Center 2)/ Koji Ikeda (ICP Development Center 2)/ Terutake Kadohara (ICP R&D Center 2)/ Takashi Ichinomiya (ICP R&D Center 2)/ Yuichiro Sugimoto (ICP Division 1)
(Front row from left) Takashi Kishi (ICP Development Center 2)/ Masahiro Kobayashi (ICP Division 2)/ Nobuyuki Inoue (ICP Development Center 2)/ Koji Sato (ICP Development Center 1)/ Yutaka Watanabe (ICP Development Center 1)


Advantages of having approx. 100% optical viewfinder coverage 

- Could you tell us about the technical background to achieving approximately 100% coverage of the optical viewfinder, and also about its advantages to users?

Inoue: The greatest advantage of having approximately 100% coverage is that it allows you to perform accurate framing using the viewfinder. As for the technical background, precise adjustments were needed in order to achieve 100% coverage. In the past, we were unable to achieve 100% coverage for the body size of this class of cameras because it was difficult to secure the space needed for adjustment. To resolve the issue, we have developed a new adjustment mechanism for the EOS 80D.

Internal Structure of the EOS 80D

A: Pentaprism
B: Built-in flash
C: Main mirror
D: Secondary mirror
E: AF sensor
F: Shutter
G: Image sensor
H: Vari-Angle LCD monitor
I: Metering sensor


- So it is impossible to achieve about 100% coverage by just enlarging the pentaprism?

Inoue: While it is also necessary to have a larger pentaprism, it is technically more difficult to adjust the viewfinder display to match the size of the image pixels. What is evolutionary about the EOS 80D, therefore, is the achievement of about 100% coverage while occupying minimal space even after these considerations are taken into account.

A: Pentaprism
B: Light Guide for Translucent LCD Illumination
C: Translucent LCD (PN-LCD)
D: Focusing Screen
E: Information Display LCD Prism
F: LCD for Displaying Information outside the Viewfinder’s Field of View
G: RGB+IR Metering Sensor
H: Eyepiece Lens


In addition to the use of a large glass pentaprism, mounting accuracy has also been enhanced to achieve approximately 100% viewfinder coverage. A transparent LCD is also used for displaying a wider variety of information.


New mirror drive system is quieter and reduces camera vibrations

- What technical efforts made high-speed continuous shooting possible?

Inoue: The maximum continuous shooting speed is about 7 fps, which is equivalent to that of the EOS 70D. However, the EOS 80D has evolved in terms of the mirror drive and bound control system. Optimising mirror drive helps to achieve quiet operation with very little shock impact during high-speed continuous shooting at about 7 fps. Where technology is concerned, we have renewed the mirror drive mechanism with the development of a new mirror drive system that is directly connected to the motor during upward and downward movements. Not only so, unlike the conventional system where operation is linked to the movement of the main mirror, in the EOS 80D the secondary mirror is also driven directly by the new mechanism.

A: Bound Prevention Mechanism for Main Mirror
B: Secondary Mirror Drive Mechanism
C: Drive Motor Unit


- What are the advantages of driving the secondary mirror directly?

Inoue: Direct drive allows us to stop the movement of the secondary mirror for the AF mechanism quickly, and this helps to enhance the precision in various aspects. The newly-developed motor comes with a built-in rotation sensor for accurate control of the drive, hence more silent operation and less camera vibrations.

- In what way does the camera reduce operation sound and vibrations?

Inoue: We slow down the speed immediately before the mirror is flipped up as well as right before the main mirror is subject to mirror shock when it is flipped down. We further reduce the speed just before the secondary mirror is subject to shock.

- Are the main mirror and secondary mirror driven by different motors?

Inoue: No. They are driven by a single motor. To be more specific, the motor drives the secondary mirror, while the main mirror moves in tandem with the secondary mirror.

- This is the opposite of the conventional method.

Inoue: Yes. There is no precedent for such a mechanism.


New metering sensor also detects near-infrared (IR) light

- Can you tell us more about the 7,560-pixel RGB+IR metering sensor?

Ichinomiya: The EOS 80D is capable of determining the colour distribution within an image by measuring the RGB colours with a metering sensor. One of the advantages for the user is that it allows for optimal auto-exposure (AE) control for human faces by utilizing skin tone detection. Also, accurate AF control is possible with the AF points for the 45-point automatic selection AF positioned over the area of the skin tone.

7,560-pixel RGB+IR Metering Sensor on the EOS 80D

- The performance of AE sensors in the past was indicated by the number of metering zones. Is zone-based metering no longer relevant?

Ichinomiya: As before, the image is divided into multiple zones for measuring the brightness and calculating the exposure. On top of this, the EOS 80D is able to control the exposure precisely according to the colour of the subject. This is partly attributable to the IR sensor, which is also sensitive to near-infrared (IR) light that is not visible to our eyes.

- From the user’s perspective, what are the advantages of being able detect IR light?

Ichinomya: There are mainly two advantages. First of all, the accuracy for detecting scenes such as outdoor greenery and sunset has improved. In addition to green, red and other visible light, these scenes also contain a substantial amount of infrared light. Detecting infrared light enables greenery and sunset scenes to be reproduced vividly. The second advantage is the minute AF differences that occur due to different light sources. Such subtle AF differences can be corrected through the detection of IR light rays.

- How has the EOS Scene Detection System changed with the introduction of the new metering sensor?

Furuya: Basically, as we have explained regarding the 7,560-pixel RGB+IR metering sensor, the advantages include higher accuracy for detecting greenery and sunset scenes, as well as greater AE and AF precision by detecting colours equivalent to the skin tone. While there are existing features for detecting sunset and greenery, the new metering sensor offers a higher level of accuracy.


Advancements and improvements that make shooting easier

- What are the characteristics of “Auto White Balance (White priority)”? 

Furuya: The existing Auto white balance setting retains a slightly warm tone when you photograph under a tungsten light bulb. This setting is also available on the EOS 80D, except that it has been renamed as “Ambience priority”. Meanwhile, the new “White priority” option reduces the effect of tungsten light to reproduce white colour in a whiter tone.

Auto White Balance (Ambience Priority)


Auto White Balance (White Priority)


- What types of scene is the “White priority” option effective for?

Furuya: It comes in handy when you want to reproduce the colour of the bridal gown in a whiter tone at a wedding, or if you want to eliminate the reddish tone and obtain a crisp white colour when photographing in a restaurant or shop.

- A Creative filter mode has been newly added to the Mode Dial. Can you tell us the intention of doing so?

Kobayashi: The Creative filter feature is also available on the EOS 70D, but on the EOS 80D, this is integrated into a new Creative filter mode along with the HDR effect to enable easier access to the Creative filter options. It was necessary to select the feature from the menu in the past, but now you can make a selection from the Quick Control screen on the EOS 80D simply by turning the Mode Dial.

A new Creative filter mode has been added to the Mode Dial of the EOS 80D.


- It is possible to adjust the dynamic range when you enter the HDR mode from the shooting menu. However, with the Creative filter mode, it seems like the dynamic range cannot be adjusted. What parameters are available in this case?

Furuya: The HDR mode of the Creative filter mode is intended for users to enjoy the feature with greater ease, so we fixed dynamic range adjustment at “Auto”.

- A new distortion correction option has been added to the lens aberration correction feature. How many lenses does the correction feature support, and could you tell us more about its characteristics?

Furuya: By default, the EOS 80D comes with correction data for 30 lenses. If the data for the lens you are using is not included, you can register it using EOS Utility. The camera is capable of storing data for up to 40 lenses. For lenses that come with built-in lens aberration correction data, correction is possible without the need to register the lens using EOS Utility.

- How does using the “Fine Detail” Picture Style affect the resulting image?

Furuya: The Picture Style feature on the EOS 80D comes with detailed options such as “Fineness” and “Threshold” for adjusting the sharpness. When “Fine Detail” is chosen, these sharpness options are automatically set to “1”. You can use it to express the fine outline or texture of the subject. Contrast is set to a level lower than the “Standard” setting, which makes it easier to bring out the texture and gradation. You can make use of this Picture Style option if you want to take a step further to produce a painting-like texture.



Ryosuke Takahashi

Born in Aichi in 1960, Takahashi started his freelance career in 1987 after working with an advertising photo studio and a publishing house. Photographing for major magazines, he has travelled to many parts of the world from his bases in Japan and China. Takahashi is a member of the Japan Professional Photographers Society (JPS).


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