Monday, September 21, 2009

Pentax K-7 Designer's Notes: Toshihiro Hamamura, Development Dept. Product Designer

Here is the first of the "designer's notes" from Pentax's team that built the K-7. These notes come from Pentax Japan and are reproduced here as translated by Pentax. It's interesting that among the details they doted over was the return to a trapezoid style for the pentaprism housing, which is a nod to the rich history of Pentax's SLR cameras.

Toshihiro Hamamura
In charge of K-7 product design
Pentax Imaging System Division Design Group, Development Department


The goal is a camera body that is the perfect partner for exclusive Limited-series lenses

At first glance, the Pentax K-7’s body may look quite different from that of previous K-series models. Unlike the delicately contoured, streamlined design employed from the K10D to the K-m, it makes use of more straight lines and shape-angled edges. However, the K-7 is not a sudden, accidental metamorphosis from previous K-series models: it is the proud successor of a Pentax legacy that dates back to the peak days of film photography.

At the beginning of the development of the K-7, the camera body designers assigned to the project team were given two formidable goals to achieve. First was to design a camera body that would make it the perfect partner for top-of-the-line Limited-series lenses — invaluable assets for Pentax. Second, to downsize the camera body to the dimensions of the *ist-D (as the K20D was felt by many to be too cumbersome). In short, these goals were set to make the K-7 the flagship model of Pentax’s digital camera lineup.

The *ist-D certainly was a good standard for size, because it was — and is — one of the smallest digital cameras ever sold. The times have changed since it was released, however. The body designers had to pack many more components — including a large three-inch LCD panel, in-body shake-reduction unit and new aperture-control mechanism — into the same dimensions. If the body designers had made a conventional approach to the design of the K-7 chassis, it was obvious even at the pre-design stage that everything wouldn’t fit into the space available.

Collaboration between design and engineering teams

The K-7 design team began a collaboration with the mechanical engineering team, even before the actual design process began. This included the sharing of 3D CAD data, and joint efforts to devise the most space-efficient layout and placement of all the components. Simply packing everything into the available space was not good enough; this might have a negative affect on the camera’s appearance or operability. The designers knew that good camera design had to start with a well-conceived chassis, before they could then begin adding on other parts and housings.

Protoypes using 3D CAD

One of the fruits of this collaboration was a shortening of the forward protrusion of the built-in flash storage compartment. In previous models, the flash discharge unit was positioned in the very front, meaning that the storage compartment also had to protrude considerably toward the front end. After reviewing and revising the positioning and layout of all internal parts, they were able to reduce this protrusion. Another stroke of luck was that one of the mechanical engineers designing the unit was relatively new to SLR design. So, unlike more experienced engineers, he was freer to use his imagination rather than be bound by conventional ideas.

Making conclusions based solely on design plans often means poor results. Because K-7 designers modeled the camera using three-dimensional CAD technology at every stage from the start of work, mock-ups were available from the initial stages.

Simple is best

The most important design goal for the K-7 was a camera body that would be a perfect partner for Limited-series lenses. In other words, the camera body had to have a design simple enough to make the Limited-series lens mounted on it stand out.

The pentaprism unit — a focal point of the camera body — was traditionally polyhedron-shaped, symbolizing the glass pentaprism it housed and demonstrating the camera’s role as a precision instrument. The K-7 shares the same characteristics as the LX, Pentax’s flagship camera in the film photography era: both have been designed to be compact and lightweight, and feature sturdy, water resistant bodies. Out of respect for this renowned masterpiece, the trapezoid motif over the Pentax logo mark was revived.

This trapezoid was also used in other models in the past, including the MZ-5, MZ-S and *ist-D. The cameras carrying this shape had varied product concepts — some were compact, lightweight models developed by returning to PENTAX’s starting point as an SLR pioneer, while others were epoch-making models born out of bold challenges. They were all, however, the first models of new lineups and marked a deviation from the past. Although designed simple and plain, the trapezoid plane featured in the K-7 symbolizes the fact that this new camera belongs to the same category as those predecessors and shares the same Pentax identity and legacy with them.

Looking at the K-7 from the side, the ridge line of this pentaprism unit is simple and straight, without any obstructing indents or folds. Stair-step indents can in fact make the body appear smaller, but this visual approach was rejected with the K-7 because it could spoil the simplicity of design. The main body was trimmed down to the point where the chassis was nearly exposed in some sections. All these features make the K-7’s optical finder, with 100% field of view, appear prominent, and give the body a prestigious and dignified look, despite the compact dimensions.

A touch of analog in digital design

Fine tuning the grip with clay mockups

Clay Model 3D Mockup

Many cameras in recent years have been designed using only three-dimensional CAD technology. For the K-7, however, there was one section that could not be designed using digital tools only: the grip. Despite today’s state-of-the-art computer technology, camera body designers cannot stick their hand into the CAD screen and actually touch the product or feel its weight. And, in fact, when the designers first picked up a mock-up constructed using only three-dimensionally digital data, the feeling was rather uncomfortable. They then added modeling clay to the grip section of the mock-up and redesigned it. When a designer is familiar with the hand-modeling process, it is in fact much faster and easier to reshape by hand, rather than revise the computer data. Once they were satisfied with what they were feeling, the mock-up was laser-scanned and the 3D measurement data was fed back into the CAD system. Because of this, the K-7’s grip was designed to be as comfortable and easy to hold as a K10D grip with a special rubber replacement grip (installed as an after-service by a Pentax service center).

“This is actually a problem for us, because we can no longer expect much profit from the grip replacement service!” joked one of the designers — but the fact is that the K-7’s grip is designed to be just that good.

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