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As has been mentioned strength is not the concern with modern plastics, especially where you a fibre re-enforced element (Carbon Fibre is a lovely material). For bodies and housings it can be a great material and people often knock cameras or lenses with a high proportion of plastic, but if the correct materials are chosen and it is well designed it can be a great material. But for the lens mount, I am not so convinced. It is all to do with how it fails under over stress conditions. Also you need to look at how its dimensional stability is over time. Many plastics creep, ie it will be fine at first but over time it starts to relax its strength so the mount may loosen. All plastics I have designed will have had elements of heat expansion or distortion or shrinkage, it depends what your materials are as to how serious it is. If it is a polymer you get the glass transition point where you get a step change in how big the thermal expansion rate is and also a change in its physical responses to stress, it is more flexible above it, and stronger but brittle below that point.
If you also look at the modern designs of high strength composite construction you will see they tend to use metal at the interface points because of the materials behaviour when you go past its maximum stress point (it takes being compressed much better). Take a look at advanced road bikes and you will see metal bonded in for the wheel mounts and also you will see sacrificial bolt on elements for gear hangers which are designed to break before the main element will. The way you can alter its properties by altering the weave is great and adds to what can be achieved. And if you look at road bikes metal frames are on the way back, kick off a long debate on merits of materials and impact on ride and life etc.
Thinking of lens mounts for camera/lens if it is a low cost item, with little chance of economic repair costs, then plastic is fine, it is past of the cost V's life equation. If it moves onto a more expensive item you would want a replaceable mount that is designed to sacrificially fail before the more expensive part of the assembly (for example if you drop it then it is better for the mount to sheer than the lens to break in half). That could be metal or plastic, but a soft metal component attached to plastic body is often a good item. With lens mounts people can miss-align them so it can be better to have a material that will gently bend on the engaging end than one that suffers a fatigue failure.
In my personal view there are a few good reasons to have a plastic body and a few good reasons to have a metal lens mount, but if designed well a plastic mount could be ok. One more reason, customers tend to see it as a low cost solution if it is a polymer solution but brand it as Carbon Fire and they will love it. In a word perception is also important. And those sort of perceptions are important in camera sales to many people.
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It would be all good if you did not drown the idea in so much words. You are not the only one with engineering experience here and claiming such must probably know that plastics yes, do creep under load (as soft metals do), but it takes time and sustained load above creep point. Otherwise we deal with elastic deformation. I think this is not a know-how for SONY engineers. There is considerable experience in industry with plastic in lenses bodies- and mount failure is not an issue with them. Here I would like to remind you that in any load bearing joint the pressure is essentially the same on both of mating surfaces. Yes, professional grade lens and camera bodies have (and will have) metal mounts - but this is a token to these devices being large investment which is supposed to last longer than the reason would probably allow. Resale value, you know. And what is an amateur camera living cycle? Maybe till next two models are out ( i.e 3-5 years).
We often see metal hubs incorporated in say, bicycle wheels - that's right, but those hubs are ball bearings and made of metal with hardness many times more than any plastic would ever possibly achieve. Not to mention that metal to plastic adhesion surfaces is a favourite place for failures under alternating dynamic loads that vehicles are subjected to.
But, to be honest, I have some ambiguous attitude to plastics due to poorly matching lids on kitchen jars Here the emotion may clash with knowledge. And I may honestly say - I would prefer metal in lens mounts. Maybe irrational, but that's what I like. So just say that - it'll do.
Further on the SLT discussion.
With the development of on sensor phase-detect autofocus as per the NEX6 and the current ethos for making things small, I can't see any logic in retaining the 'A' mount in the long term - other than to keep customers from stomping off elsewhere. That's really rather annoying as there are currently some nice prices available on lower end SLTs and they look quite attractive for using legacy lenses (i.e. my old Carl Zeiss Jena stuff), so if there is a reason / strategy for keeping the A mount long-term the SLTs would be a nice proposition.
Incidentally, I was under the impression that the reduction in size by getting rid of the mirror-box means that a shorter distance between the back of the lens and the sensor is possible and that facilitates the design of less bulky (and heavy) wide-angle lenses.
Giving up to some wild fantasies, nothing inhibits SONY from making a mirrorless camera in ... SLT body. It seems to be the way their eternal competitor PANNY is going now. And create A-s (see EF-s) lenses that will sink deeper in the body - so the whole package gets shorter. Legacy lenses will work of course.
I think secretly, Canikon have been envious of Sony's SLT technology, they seem to be stuck in a time warp, don't get me wrong, both Nikon and Canon are excellent systems to buy into but are very conservative companies for anything radical. I guess Canikon work on the assumption, if it aint broke don't fix it.
SLT on the other hand has given Sony a new direction to take which can only be mirrorless eventually, mainly to save space and make smaller bodies. Sony's NEX is doing OK and can look after itself, but its the future of the A mount. I think it will continue.
Sony have opened up more in house A mount lens production and there are new lenses rumoured. I don't think these are the actions of a company about to drop one of its lines. Sony are a massive electronics giant like Panasonic, and can afford to put sticking plaster over some of their ailing products with out having to drop them. One thing has always been a bit unclear, just who is the Sony A mount SLT been in competition with, DSLR's or the M/4/3 lot, or both or none.
I think the Sony SLT system is great, and it works for me although I do understand those who don't like it. Inferior image quality because of the SLT is a myth and quite often better than the some of the competition. I love Canikon and Pentax and have great respect for them but Sony gets my full support and I hope they come out and surprise us all again with new radical designs.
Quote: I think secretly, Canikon have been envious of Sony's SLT technology, they seem to be stuck in a time warp, don't get me wrong, both Nikon and Canon are excellent systems to buy into but are very conservative companies for anything radical. I guess Canikon work on the assumption, if it aint broke don't fix it.
That's a fair assumption, but consider this:
For SONY all photo camera business is rather a sideline than main source of profit. Being huge corporation they may afford toying with something relatively small. For Canon and NIkon camera business is a prime, so they thread more carefully, however it does not mean they are blind to tendencies. Nikon 1, EOS M and EOS100D are definitely into competition ( however fairly bleak at the moment) with MFTs and M4/3s. Should Canon and Nikon get a taste of it - we will see a bit later.
Quote: For SONY all photo camera business is rather a sideline than main source of profit. Being huge corporation they may afford toying with something relatively small. For Canon and NIkon camera business is a prime, so they thread more carefully, however it does not mean they are blind to tendencies. Nikon 1, EOS M and EOS100D are definitely into competition ( however fairly bleak at the moment) with MFTs and M4/3s. Should Canon and Nikon get a taste of it - we will see a bit later.
Sony have been losing money for years in most of their divisions - though not quite as much as Olympus - but they've returned to profit this year. And I don't think Sony would regard their camera/sensor divisions as a "sideline" - probably more as sensible diversification. Canon and Nikon have been profitable for years but it's interesting to note that profits from both of their digital camera divisions have been declining pretty steeply recently. In the case of Canon it's down to falling profits on DSLRs and in the case of Nikon it's because the Nikon 1 mirrorless cameras haven't been well received.
Both Nikon and Canon have deliberately chosen to design their mirrorless cameras so that they don't compete with their DSLRs. They may come to regret this. The lesson of history is that the manufacturers who have the courage to take a risk and make their "land grab" early tend to reap the big rewards. Micro 4/3 has a big start on all the other mirrorless cameras and I reckon it'll clean up.
Your probably right on most counts, breaking into the CSC market is a big risk for those following Panasonic, Olympus and Sony. M/4/3 is currently the CSC market leader and I cannot see them being challenged much by Canon or Nikon and certainly not Pentax who are really struggling with that format.
People who buy into Canon and Nikon are probably buying the name [because of their reputation] rather than the cameras are the best on the market.
The EOS 100D is a weird departure from the DSLR standards and it has not done that well so far, but lets wait and see. I certainly did not like holding it compared to other EOS D cameras.
Agree about Sony, I don't think they worry too much about loss making lines, but they do strive for prestige in the market place, no matter how small the product is and they are getting there with their cameras, but, that could equally apply to Panasonic and Samsung. Now there's a camera that does not get the recognition it deserves. In a way the NX-20 is the best of both worlds. DSLR shape and sensible size, EVF, CSC system, APS-C format and superb lenses and IQ better than some high end DSLR's, all at excellent prices. Trouble is, some people would rather have a well known name round their neck rather than the name of a company more famous for its 'flat screens'.
The world of digital cameras is not standing still and developments are coming thick and fast, some times its hard to keep up with whats new to the point of being bewildering.
With the development of on sensor phase-detect autofocus as per the NEX6 and the current ethos for making things small, I can't see any logic in retaining the 'A' mount in the long term - other than to keep customers from stomping off elsewhere.
The logic is that Sony inherited a big user base when it bought Minolta. They lost a proportion of it when they dropped DSLRs for SLTs but it's a still a big user base and they now have all the development in place, plus a good lens range. NEX is a good system but it's up against m4/3 and will probably lose.
Of course a NEX camera can be simply turned into an SLT by buying the Sony adaptor (which includes the pellicle mirror and PDAF sensor) - or alternatively the simple adaptor that allows use of the in-camera focusing system. So when the NEX system has put PDAF into the camera sensor you can just buy the simple adaptor and use the A-Mount lenses with no loss of functionality. The only thing missing would be the in-camera IS - the NEX bodies are too small for this - which is particularly problematic because IS is mainly required for long lenses and the NEX system doesn't have any. However, something like the new A3000 could incorporate in-body IS. So Sony could just market E-Mount cameras in two forms - the small ones, for those who like this, and the slightly larger DSLR-like ones with IS for those who want to use long Alpha lenses.
If I had to move over to NEX for whatever reason, I would much prefer the A3000, because I like DSLR shaped bodies and I prefer them up at the eye rather than a NEX 7 for example.
My be the A3000 is a sign of things to come. Hmm, I think if A mount went I would go with it.
Being not a big fan of SONY I missed on this one - A3000. It looks like Sony tries to make things right after all (from my point of view of course). I wonder how many customers will be lured off Panasonic G (5,6) cameras those become ridiculously overpriced. And it is what Canon should have done instead of producing an IXUS with EOS sensor in it and EF(M) mount on. Bravo! Now all they need to do is to bring the sensor with phase detection focusing, better screen and EVF, and put A mount on - and they have the line of cameras that will satisfy if not all then many. It looks like my wild fantasy (see above) goes in step with SONY reality.
Quote: Now all they need to do is to bring the sensor with phase detection focusing, better screen and EVF, and put A mount on - and they have the line of cameras that will satisfy if not all then many.
The E-Mount can already be converted to the A-Mount by the simple addition of the Sony adaptor, which effectively just moves the lens a bit further away from the sensor. Sony already have PDAF sensors (in NEX-6, A99) and the screens and the latest EVFs are as good as they need to be IMO. All they need to do now is to put IS into the E-Mount camera body (for larger cameras like the A3000) and they have all the Alpha functionality in an E-Mount camera.
This is the way that Olympus have approached their "professional" m4/3 cameras such as the EM5 and the new EM1. You can put a 4/3 adaptor on them, add a 4/3 lens and you're effectively using a 4/3 DSLR (without the mirror). The only fly in the ointment for Sony E-Mount is that their E-Mount cameras don't have IS built in, but this would be a very simple matter to rectify.
The Sony A3000 is such a low spec, its almost a joke, only the low price saves it. I can't help thinking that it was put out on the market to test the water and possibly a sign of better things to come.
I think most M/4/3 cameras such as the Panny G5/GH3/G6 are going to stay expensive just like Olympus are. If you are not into this smaller format any of the current DSLR's from Canon, Nikon, Pentax and Sony SLT's are going to give you most of what you want. It is possible that Sony might do what Olympus did with their OM-D E-M5 and now EM-1 where an adaptor is available for the older 4/3 lenses, this idea could be adopted for fitting an A Mount lens onto an E Mount body, thus making the body smaller. I'm not hugely impressed so far with the Sony NEX lenses but being able to use an A mount lens would be a great incentive to stick with the brand.
I think Sony A mount will be mirrorless by next year and they will have cracked the on sensor metering and focussing. I also hope that IBIS is retained.
Quote: The Sony A3000 is such a low spec, its almost a joke, only the low price saves it. I can't help thinking that it was put out on the market to test the water and possibly a sign of better things to come.
Although A3000 does not look too attractive to a demanding enthusiast, this camera may surprise. The only thing that SONY have possibly done wrong with it was the low-res EVF (some superzooms have better) - but this would not be too hard to fix with the next release. Yet, quality sensor and decent optics at competitive low price may attract more than a few casual users. Also, as I have mentioned above, it may be the start of future line that may include higher class cameras - like Canon does with their EOS####D,EOS###D,EOS##D and EOS#D. You get the idea - the less the number, the higher specifications. It would not be too unusual to have two types of mounts for different levels - "professional" Canon series don't take EF-s lens for example.
I wonder though what makes some photographers so uncomfortable with honed to perfection DSLR type ergonomics?
Yes, it might be the start of a new line up, entry, middle and pro or high end enthusiasts.
I'm sure Sony are trying to consolidate their range into recognised catigories with the appropriate status and price for each model.
I have always liked holding and using DSLR bodies compared to smaller range finder type compact bodies, but then I'm old school having been brought up on 35 mm SLR's.
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