Canon global

The new VIXIA HF G10 (LEGRIA HF G10) consumer-model video camcorder incorporates the same imaging technologies as professional camcorders, enabling high-quality video capture at a higher level than previous models. Were there many problems getting this technology into a consumer camcorder?

Nakayama

Considering that [general] users are not professional videographers, there were countless issues we wanted to address in a certain way. I think these users generally point their camcorders without thinking about the conditions in which they are shooting, so we wanted to reduce the occurrence of such problems as whiteout and underexposure in scenes that contain both dark and light areas. To address this, it was necessary to expand the camcorder's dynamic range (the range from dark and light that a camcorder can accurately capture).

Koizumi

At the sensor level, the dynamic range in the HD CMOS PRO we developed is 2.8 times that of the previous generation of CMOS sensors. Gradation is also smoother than in the past.

Improvements to photo diodes contribute to an expanded dynamic range and enhanced gradation expression.
This makes possible beautifully reproduced scenes with dramatic contrast

Nakayama

We also added a function that automatically applies the optimal settings for a scene by identifying the type of scene being shot. This feature, called Smart Auto mode, automatically adjusts the camcorder's settings based on such factors as the movement of people if present, the distance to the subject, brightness and color. This is the kind of function that lives up to the expectations of consumer video camcorder users.

Tell us a little more about the newly developed lens. How did you reduce the lens aperture while also achieving the wide-angle functionality and high image quality on par with that offered by cameras used in television broadcasting?

Horiuchi

An ordinary consumer-use camcorder lens is made up of four lens groups, with two of these moving forward and backward to provide zoom functionality. However, attempts to increase the field of view without lowering image quality in this configuration increased the size of the lens, making it too large for use in a consumer video camcorder. In order to make the lens more compact, we utilized a design in which three of the four lens groups move. This made it possible to create a wide-angle lens with high image quality.

Structure of the newly developed lens groups and the previous lens groups

So you went from moving two lens groups to moving three lens groups? That doesn't sound like such a great leap of imagination...

Horiuchi

Admittedly, we had thought of it before. However, moving three groups is technically difficult to achieve. The reason for this is that the third lens group, which was not previously used for zooming, is the image stabilizing shift-lens group used to correct for camera shake. This image stabilizing shift-lens group moves left, right, up and down in real time, and is now used for zoom functions by also moving backward and forward.

Movement and mechanical structure of the shift lens (3-D real-time lens mechanism)
The single lens group moves freely in real time to provide both zoom functionality and image stabilization

I see. So that's how it's done. It must've been difficult to control the mechanical operation of the three lens groups.

Nakayama

Yes, it was. It was very difficult to develop the embedded software used for control. With video, movement while zooming must be smooth, and we faced a series of difficulties because we also had to automatically control the aperture while zooming.

Horiuchi

Actually there were also issues with the mechanism itself. Although we managed to enable the third lens group to smoothly move backward and forward while shifting upward, downward, left and right, we found that the lens sometimes moved too much and went past the appropriate position during image stabilization. We had to do something about it and damper proved to be an effective solution to the problem. We learned that damper might do the trick at just the right time during the lens development process, and found that they provided optimal movement once we tested them. Damper were essential for the practical application of the movement of the three lens groups.