Some engineering thoughts about Ricoh GXR design.

Started Apr 10, 2013 | Discussions thread
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wayfarers
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Some engineering thoughts about Ricoh GXR design.
Apr 10, 2013

Please accept my apologies, I will not be able to respond to any comments.

Advanced camera bodies are typically carbon fibre reinforced polycarbonated with or without structural metal sub chassis, die cast magnesium chassis, or mix of various technologies. Just about all modern approaches are suitable for the purpose and, when done properly, result in small, robust bodies. In destructive tests polycarbonate bodies (usually referred to by a generic and imprecise term as "plastic") tend to bounce back and when the impact is increased, eventually break (or shutter), while the die cast magnesium boxes take most of impact without bouncing, transferring the energy to the internal components, and tend to crack first before they shutter. This is a very short summary, full of generalizations and omissions, not a proper analysis.

So, you may ask, which design is better for camera bodies? I will not even attempt to answer that, specially that there are many other design approaches which include mix of various techniques, and also use of polycarbonate and press metal sub chassis, for example Fujifilm X-E or Olympus PEN series. The GXR body design is modular, thus the body parts did not have to be machined to very high (and thus increasing cost) tolerances, mainly because the optical elements were separated in the lensors. While very nicely constructed there were some areas which could be improved in future versions, specifically: incorporating environmental body sealing and changing the hand grip design.

The body sealing in this class and design is not unusual, but not given, a few examples both ways:
* Panasonic Lumix DMC-GH3, magnesium alloy body, is weather sealed (dust/splash proof)
* Various Leica models (M8, M9, etc., also so called "Safari" editions) use a two-piece magnesium alloy cast, the top and the base plates are milled from a single block of brass (old fashioned and questionable design decision), but there is no weather sealing. See:
http://www.dpreview.com/previews/leicam9/3
http://www.chuckhawks.com/leicaM9_camera.htm


The grip construction is poor: rubber based external grip covering and a small back cover are simply glued to the body. This with time and exposure to higher temperatures will cause the rubber material to deform, and subsequently to loose cohesion and fall off with time. There are examples of similar errors made by just about every manufacturer (example: many older Nikon metal bodies suffered identical issues). But there are also examples of proper design: a handle should be manufactured as a separate component and rubber or plastic should be fused (not glued) to the handle in a separate manufacturing step, before the handle is mounted to the body.

Apart from the above mechanical design of the GXR body is designed very well. The only potentially mechanically weak point, the bridge connecting the grip area with the thin base platform for the lensors is stiffened by the top and back sections, thus there is absolutely no problem with rigidity, and assembled body is example of good, light and rigid box-like construction.

For the sake of completeness I have also attached a photo which shows mechanical design of the lensor. Interesting thing to notice is that the lens and sensor are separated from the lensor frame/base, thus there is no need for any shimming between the lensor base and the sensor. To assure perfect optical alignment between the lens and the sensor the adjustments were done separately  before placing the lens/sensor sub assembly into the frame. Aligning sensor and lens is almost always an issue with top range cameras - never publicized by manufacturers (but this, of course, is a completely separate topic).

A few photos illustrating my points follow.

GXR body parts

GXR body, front

GXR lensor before mounting lens and sensor assembly

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