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06-01-2012, 04:45 AM   #16
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QuoteOriginally posted by Anvh Quote
Sounds like you're saying that all composite materials have thermal expansion problems, thank god they don't make aircrafts out of them... oh wait...

No camera body would break due to expansion problems. A camera body itself (not the electronics, the battery, or lens and/or pentaprism elements) could easily take minus 50 fahrenheit or more than 150++ fehrenheit. Now if it were a physical part; or one subjected to extreme stress (such as a moving vehicle of sorts); then it's a whole diferent story.

On a side note Pentax once made an Efina T; which everyone wrongly thought was titanium; it wasn't. Nikon has a soon to be released F4 coming out soon; yet by the end onf the year there will in fact be a (real) titanium version of it. They even make titanium notebooks. Even stranger, HP has one with most of it's outter shell made of glass

06-01-2012, 05:47 AM   #17
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QuoteOriginally posted by Anvh Quote
Sounds like you're saying that all composite materials have thermal expansion problems, thank god they don't make aircrafts out of them... oh wait...

Yes they do (and never the whole plane, just small parts), and all the expansions have been very well calculated.
A stainless chassis and bidy would make a very heavy camera, that's why parts are made out of poly carbonate. It is alot easier just to use one material, as bonding two different materials is very, very difficult. As I just wrote, stainless tseel would make a heavy camera. just polycarbonate would make a very light one, but very fragile. Yes it has fantastic weight to strenght ratio, but it is very fragile to some forces. And that is where magnesium (or titanium) comes in play. fantastic weight to strenght ratio, but it has some drawbacks. mainly it is very expensive. Which is because magnesium is just expensive. and second it is very expensive to work with. it has to be machines with expensive (oil)metalworkingfluids. waterbased fluids will just ruin the magnesium. And there must be taken extra precausions with heat/fire. As when magnesium starts to burn, well good luck with trying to extinguish that.
06-01-2012, 05:52 AM   #18
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Magnesium is never used on its own, it's too volatile of a material, it is usually combined with aluminium. This makes for a relatively light and robust chaise with the ability to injection mould the frame (quick and inexpensive). most laptop chaises are magnesium alloy these days. Stainless steel/polycarb in my understanding would be slightly heavier, but allot stronger in it core strength. My guess is that the chaise is polycarb with a SS core for torsion strength.

IMO this is going backwards in technologies. SS/Polycarb was the chaise of devices and laptop in the 90's and early new millennium. now you will find that most things are Magnesium Alloy. And as mentioned above it is the better choice because of it ability to disperse heat quickly.
06-01-2012, 05:59 AM   #19
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A major consideration for cameras is maintaining the lens and image plane in correct relationship. Stiffness of the body components and accuracy of manufacture are key elements. I expect polycarbonate requires the reinforcement of stainless components largely for stiffness and strength, just as the composite aircraft use reinforcements like carbon fiber for the same reason.
Magnesium is a very easy metal to die-cast and machine to precise dimensions, usually at lower tooling and piece cost than aluminum. (Which is a major reason it was used for the engine and transmission cases of the original air-cooled VW Beetle.) Although magnesium is softer and not as stiff as (heavier) aluminum for die castings (which is why VW went to aluminum cases for the later Bus engines), it's properties are a good fit for a camera body chassis. Magnesium die-casting wasn't used much in the USA, so it sounds exotic here; but it's a logical choice for high-end camera bodies.

06-01-2012, 07:53 AM   #20
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QuoteOriginally posted by Macario Quote
Yes they do (and never the whole plane, just small parts), and all the expansions have been very well calculated.
Sorry for you i work with aircrafts.
Look up Glass Laminate Aluminium Reinforced Epoxy and see how much the Airbuss 380 use it and as fr as i know most modern aircraft use glare for their skin.
For fun look up the B787, that one is 80% made out of composities, the whole fusalage of the 787 is one piece of carbon reinforced plastic




I kinow they use 50% here and that is correct for mass, 80% is volume.

Last edited by Anvh; 06-01-2012 at 07:59 AM.
06-01-2012, 10:53 AM   #21
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QuoteOriginally posted by Anvh Quote
Sorry for you i work with aircrafts.
Look up Glass Laminate Aluminium Reinforced Epoxy and see how much the Airbuss 380 use it and as fr as i know most modern aircraft use glare for their skin.
For fun look up the B787, that one is 80% made out of composities, the whole fusalage of the 787 is one piece of carbon reinforced plastic




I kinow they use 50% here and that is correct for mass, 80% is volume.
You are right when looking at it like this. But I never looked at Glare as a comosite as such, as it still needs aluminum as reinforcement (never worked with planes, but used to supply the boeing and airbus. SO also no a bit of it). As the aluminum still ment work for us ( we would have been out of buisness if it would be full carbon/plastic composites).
But would't it be cool to have pentax camera made out of glare. The adds would be so cool: Pentax, the pictures you take with it will make you fly
06-01-2012, 10:27 PM   #22
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Thanks for the replies. I included some pics of the K30 vs. K-5 body for comparison in case anyone didn't see it before. However, is the picture of the K-5 body inaccurate?

I just found this photo, which includes a picture of a K-5 made with transparent plastic, right next to a k-5 metal body:
PENTAX K-5 (K5) | Flickr - Photo Sharing!

However, in the picture you can see right through the transparent plastic, and it just has plastic in locations where the k-5 looks like it should be metal. So is the K-5 metal body picture just a mockup?

Anyways, it sounds like the purpose of a magnesium alloy chassis allows the construction of a camera in such a way that it would be either heavier, not possible, or more difficult to construct with a stainless steel/polycarbonate chassis. Once constructed though, the magnesium chassis doesn't give any additional benefit to the photographer. Would that be an accurate assessment?
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06-02-2012, 10:28 AM   #23
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QuoteOriginally posted by Macario Quote
You are right when looking at it like this. But I never looked at Glare as a comosite as such, as it still needs aluminum as reinforcement (never worked with planes, but used to supply the boeing and airbus. SO also no a bit of it). As the aluminum still ment work for us ( we would have been out of buisness if it would be full carbon/plastic composites).
But would't it be cool to have pentax camera made out of glare. The adds would be so cool: Pentax, the pictures you take with it will make you fly
well the B787 is going full carbon almost so your days might have been numbered

I doubt they will benefit from glare, they dont need the strength but carbon might be nice.

06-02-2012, 10:32 AM   #24
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QuoteOriginally posted by sahale Quote
Thanks for the replies. I included some pics of the K30 vs. K-5 body for comparison in case anyone didn't see it before. However, is the picture of the K-5 body inaccurate?

I just found this photo, which includes a picture of a K-5 made with transparent plastic, right next to a k-5 metal body:
PENTAX K-5 (K5) | Flickr - Photo Sharing!

However, in the picture you can see right through the transparent plastic, and it just has plastic in locations where the k-5 looks like it should be metal. So is the K-5 metal body picture just a mockup?

Anyways, it sounds like the purpose of a magnesium alloy chassis allows the construction of a camera in such a way that it would be either heavier, not possible, or more difficult to construct with a stainless steel/polycarbonate chassis. Once constructed though, the magnesium chassis doesn't give any additional benefit to the photographer. Would that be an accurate assessment?
That clear plastic is just "show off" model for display, nothing more.

As for magnesium vs plastic, the magnesium might provide EMI shield which plastic won't, how much use it would have...?
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