South & Southeast Asia
South & Southeast Asia
When Canon users are asked how we can improve older products, many say they’d like us to add IS. EF16-35mm f/2.8L III USM does not feature IS, but to tap the potential of RF L lenses in offering image quality with IS, we worked to design a comparable lens with five stops of image stabilization under CIPA standards.
The trickiest aspect of incorporating IS is positioning this unit. Opinions were divided among our optical and mechanical engineers. The optical engineers wanted to incorporate IS on the image sensor side for higher image quality, and the mechanical engineers wanted it on the subject side to keep the lens compact. Each team argued to support their position. IS on the sensor side does improve stabilization accuracy, but faint electromagnetic waves from the IS unit may cause noise in images. Positioning an IS unit on the subject side makes the drive lens sluggish. Neither team emerged as the winner, and we decided to keep the unit in the current position, in group 4. The design process came to a close with each team arguing over 0.1 mm here or 0.1 g there, but we ended up creating a solid product.
In other details, we focused on how the lens and camera work together. Some photographers assume that landscape shots require a tripod, but we wanted to change this thinking, if only a little. To reduce the need for a tripod and enable shooting from many angles without worrying about camera shake, we kept in contact with the camera team nearly every week working on coordinated IS, as performed both by the lens and the camera. Working out the specifications took many online meetings, and after prototypes were ready, we met several times in person to refine this system.
Another key point in lens development was focusing precision. Merely having precise focusing was not enough. Since the EF era, more users than ever have been recording movies, so there was a need to develop a lens group capable of smooth, fast focusing for movies. To ensure smooth focusing, it was a priority to make the lens lighter. This lens, like EF16-35mm f/2.8L III USM, uses the three elements in the second groups to focus, but the lens configuration of that lens was too heavy to use without some changes. It would require a sophisticated mechanical structure. Instead, we revised the lens configuration of RF15-35mm f/2.8L IS USM to enable a smaller lens diameter for the second lens group, which reduced the weight.
Now that the focusing group was controlled directly, we succeeded in developing a fast, smooth focusing group.