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[Part 2] Technology Behind the “Ultra-High Resolution”

With the release of the EOS 5DS and EOS 5DS R just around the corner, I have conducted an interview with the development team to understand more about the new technologies introduced on this 50-megapixel ultra-high-resolution camera as well as the challenges involved in its development. (Reported by Ryosuke Takahashi / Photos of interviewees by Takehiro Kato)

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(Back row, left to right)
Kunihiro Shirai: ICP Design Dept. / Hiroyasu Morita: ICP Design Dept.
(Front row, left to right)
Mineo Uchida: ICP Design Dept. / Toshifumi Urakami: ICP Design Dept. / Kisyoshi Tachibana: ICP 2 Products Planning Dept.

Newly-developed mirror vibration control system

- What were the enhancements made to the AF system in response to the larger pixel count?

Urakami The AF system on the EOS 5D Mark III is basically inherited on the EOS 5DS series, but their subject tracking performance by EOS iTR AF is enhanced with the use of a 150,000-pixel RGB+IR metering sensor.

- What was the reason for not changing the AF sensor? Was it because the performance of the system on the EOS 5D Mark III was good enough?

Urakami Yes, you are right. The EOS 5D Mark III and the EOS 5DS series share exactly the same principles of forming an image on the focal plane. It can handle any number of pixels as long as the level of accuracy is maintained. The existing AF sensor is perfectly fine since it has a sufficiently high level of detection performance.

- The maximum resolution of about 50 megapixels and the continuous shooting speed of about 5 fps are simply remarkable. Are there any efforts that are worth special mention?

Morita While this is also applicable to cameras other than the EOS 5DS series, it is necessary to ensure that the firmware allows for the smooth operation of the series of systems from data loading by the image sensor to data processing by the image processor and data recording after converting the file format. It is the first time for the firmware to handle a data size as huge as 50-megapixels, and we have put in a lot of effort into the various firmware processes, including the transfer of data between the two DIGIC 6 processors.

- What changes were made to the existing firmware following the upgrade of the pixel count to about 50 megapixels?

Morita The huge amount of data has a significant impact on the firmware. In order to ensure speedy and smooth data processing under such conditions, advanced and complex processes are needed, such as parallel processing while switching between the memory spaces. As there is limited space in the built-in memory of the camera, it is important to consider how this space can be utilised most effectively.

- How is the mirror vibration control system different from the existing ones?

Urakami One of our goals was to minimise vibrations within the camera when we first started on the development of the EOS 5DS series. To do so, it is necessary to reduce both the "inertial forces of the components for moving the mirror" and the "collision energy during mirror lockup". After many trials, we finally got the hint from the mirror control system on the EOS 7D Mark II, which drives the mirror directly using the motor in order to achieve a continuous shooting speed of about 10 fps using the limited power supply. A part of this mechanism has been incorporated into the EOS 5DS series. However, since it would not be possible to include all the components in the mirror unit of the EOS 7D Mark II for enabling high-speed continuous shooting, what we did was to optimise and simplify the entire system for the EOS 5DS series. This led us to the development of a new system that operates the mirror using only a cam for flipping up the mirror and a small cam for flipping it down. Adopting a smaller cam would naturally mean a lighter weight, which helps to reduce the inertial force that is generated by the movement of the mirror components.

- Am I right to say that both the existing and new vibration control systems make use of cams, but differ fundamentally in the way the cams are used?

Urakami Yes. It is really simple, unlike the movement of the EOS 7D Mark II. That being said, the movement of the motor is reflected in the movement of the mirror, which makes speedy control easy. Particularly, the shock impact when the mirror flips up and hits the stopper has been reduced on the two models of the EOS 5DS series. For existing systems that flip up the mirror using the force of a spring, the mirror would hit hard against the stopper. With the new system, the energy during collision can be reduced to an even lower level by controlling the speed of the mirror.

- Wouldn't it consume a lot of battery power if the mirror is driven only by the motor?

Urakami A system that combines the use of a spring would require the mirror to be charged while suppressing the force of the spring, during which a heavy load is being imposed. As this is not required on the new system, it is possible to reduce power consumption even when the mirror is driven only by the motor. Operation is not subject to unnecessary load, so we adopted the same motor that is used on the EOS three-digit and four-digit models.

Mirror Vibration Control System

  1. Down Cam Gear
  2. Up Cam Gear
  3. Mirror-driving Motor
  4. Sub Mirror Bound Suppression Mechanism
  5. Main Mirror
  6. Down Spring
  7. Down Cam Gear
  8. Up Cam Gear
  9. Main Mirror Balancer
  10. Mirror-driving Motor

While the basic concept is identical to that of the EOS 7D Mark II, the vertical motor for driving the mirror has been miniaturised. Also, a cam gear specially dedicated to flipping down the mirror has been omitted. Now both the mirror up and down movements are driven directly by the motor.

Thoroughgoing anti-shake measures

- Generally, it is said that camera shake becomes more prominent with a higher pixel count. Is it possible to eliminate all shake-related issues simply by raising the shutter speed?

Urakami Yes, raising the shutter speed helps to solve the problem, but it is not possible to obtain a fast shutter speed in some scenes. For example, the shutter speed naturally decreases when you are photographing a nightscape. This is why we have introduced different measures, which include the development of a new mirror system.

- Is there an easy-to-understand way to determine the shutter speed based on the focal length?

Urakami This is my personal view, but a rule that would be rather useful is to increase the shutter speed by about one stop from "1/focal length". That being said, it is still ideal to set the camera on a tripod, since it would not be possible to eliminate camera shake fully if you are taking a handheld shot.

- What are the advantages of the new user-selectable shutter release time lag setting?

Urakami This system was proposed by our mechanical design team. Various efforts were required to suppress camera shake on the EOS 5DS series. However, some factors are not determinable by us, such as the strength of the tripod that users are using, and the focal length of the lens. We have therefore come up with another way to suppress camera shake during a slow shutter speed, which is to allow for manual setting of the shutter release time lag. By lengthening the time interval up till the shutter is released, you can capture a shot after the shock impact from mirror lockup is diffused, which we believe will come in handy when the tripod strength is not sufficient or for lenses with a long focal length.

- What efforts were devoted to the body structure and material when addressing camera shake?

Urakami Glass fibre is employed for the material of the camera body, and we have increased the proportion to enhance its robustness. At the same time, we have also adopted a thick stainless steel material for the base chassis, and modified the structure of the tripod mount. We strengthened the tripod mount by designing it as a separate component through ingot casting.

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New noteworthy features

- I realised that a new "Fine Detail" Picture Style has been added when I looked at the features in greater detail. How is it different from the existing Picture Style effects?

Shirai As the name suggests, this Picture Style places emphasis on the details. Sharpness is more refined compared to the standard level. The standard sharpness setting has a thick outline, which seems to give the image a high apparent resolution at first glance. However, this also makes it difficult to sharpen the details of the subject. Meanwhile, the "Fine Detail" Picture Style makes it easy to produce sharpness up to the details of the subject, while stressing the outline at the same time. With this new addition, it is now possible to reproduce the texture of the subject in greater detail. Contrast is slightly subdued compared to the standard setting, so it will be easier to express the gradation of highlight tones. The colour tendency uses the standard setting as a basis, so you can obtain data as it is with no adjustments made.

- Can you provide a simple explanation for the entry-level users on the [Fineness], [Strength], and [Threshold] parameters in the sharpness setting?

Shirai From the perspective of image processing, [Strength] is a parameter for adjusting the sharpness range. Raising the [Strength] level widens the range, thus enhancing the contrast of the entire image. In other words, this is a rather powerful parameter that is able to add more contrast to our first impression of the image. The [Fineness] parameter is one that directly determines the fineness of the sharpening effect. Lowering the [Fineness] level refines the sharpness, while raising it enhances the edges with thicker outlines. You should therefore raise the level if you want to emphasise the outline, and lower it if you want more delicate expression of the subject.

- So now we are left with the most confusing [Threshold].

Shirai [Threshold] is for determining the area for edge enhancement. That is to say, how much of the image is to be regarded as the edge when sharpening is applied. The lower the [Threshold] level, the smaller will be the area for edge enhancement, and sharpness will be applied to finer details for more delicate expression. However, note that during high ISO speed shooting, noise components will be regarded as the edge when the [Threshold] level is lowered excessively, and this may cause noise to seem more prominent as a result.

- Can you tell us how we can make good use of the Crop Shooting feature?

Tachibana This feature allows you to enjoy a pseudo-telephoto effect, while it also expands the relative size of the AF area at the same time. We have received many requests in the past to expand the AF area outward, but this was a challenging task due to the structure of the phase-difference AF. With the relative expansion in the size of the AF area using the Crop Shooting feature, framing is now made more versatile. Favourable feedback has also been obtained from professional photographers who have taken trial shots using this feature. Of course, since there are sufficient pixels, you can create a pseudo-telephoto effect while maintaining the image quality.

Viewfinder Coverage Display

While the basic layout and performance of the AF sensor are basically the same as those of the EOS 5D Mark III, using the 1.3x or 1.6x Crop mode helps to expand the relative size of the AF area. In the 1.6x Crop mode, the AF points are able to cover almost the entire area in the horizontal direction. Also, AF performance does not vary when the Crop feature is used.

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Different details at a closer look

- What does the Customizable Quick Control feature do?

Tachibana This feature was included in response to our users' feedback. There were voices such as settings they wanted were not available, or some items were not necessary to them, so we made the Quick Control Screen customisable to meet the needs of different users.

- Compared to the EOS 5D Mark III, what advancements were made to the movie feature?

Morita Advancements were rather normal compared to before, such as the introduction of the Movie Servo AF. The most noteworthy evolution would be the Time Lapse Movie function, which carries out image development within the camera after capturing a series of still shots, and saves the resized data as a movie file in the ALL-I format.

- What is the biggest reason for inheriting the design of the EOS 5D Mark III?

Urakami The biggest reason is to let everyone know that they belong to the same family as the EOS 5D Mark III. They would no longer resemble the EOS 5D series if we made too drastic changes. At the same time, however, we also aim to convey the message that "ultra-high resolution = special and top-class" through the robust design around the pentaprism area on the EOS 5DS series. Other details that differ include the slightly larger Canon logo mark, so the EOS 5DS series is not exactly identical to the EOS 5D Mark III. Not only so, an electroformed Mode Dial is employed instead of a colour-painted one. We hope that these details will give a more elegant feel to the camera and add to the joy of owning it.

- Lastly, please give a message to the users.

Tachibana The EOS 5DS series is the first in the EOS series to exceed 50-megapixels. New features and efforts have been incorporated for you to make full use of the high pixel count and enjoy the strong resolving power. They are not just models that come with a new image sensor compared to the EOS 5D Mark III. Please look forward to its release with great excitement.

- Thank you very much for your time today.

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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