If the A5xx had all the features an enthusiast could want, including MLU, dual dials, dof preview etc...
Why would anyone buy the A7xx when it is released?
It used to be that the more you paid for a digital camera, the better image quality (sensor performance) you expected. As technology and manufacturing capabilities advance, better image quality is attainable with cheaper cameras.
If Sony wanted to, they could have made the A5xx cameras everything that any enthusiast could ever want - for only a few dollars more.
They left out the enthusiast level features on purpose, to ensure that enthusiasts spend more money on the more expensive A7xx when it is released, in stead of opting for a cheaper camera that offers the same IQ and performance.
I really really hope I'm right - because that would mean that there is hope that the A7xx will be a real photographer's machine.
True that is
a way of looking at it and they way Sony likely does. I would separate the cameras on
real cost - rear control dial, better build, better OVF (pentaprism), larger buffers, AF/MF button, etc - not by not including what I consider
basic functionality. Even if the A5XX had all the missing features I would still be interested in the A7XX because of the presumably better build, controls, buffer, etc.
This is very much similar to the way Mark Weir of Sony described the A550 to me - a camera that has certain higher-end features, such as 5-7 fps, HDR, new and improved sensor and imaging chain, all in a lower cost body.
One question that nobody here knows the answer to is the extent to which the use of a lower end body may have necessitated the non-inclusion of certain features, or had nothing to do with it. DOF is a largely a mechanical operation on Alpha cameras (as opposed to Canon for which it is an electronic function because of the mount design). Perhaps the lower cost body precluded including the feature in order to hit a certain price point. Dual control dials obviously are a higher-end body feature and more expensive to implement.
On the other hand, some missing features would seem to clearly be camera software or firmware matters, such a program shift and mirror lock-up or pre-fire. Those items, particularly program shift, would seem more easy to include and not have much, if any, added cost. (However, I would note that in reality, the only Sony body with a mirror lock-up feature where the photographer can first raise the mirror, then release the shutter at his or her desired time, is the A900/850. The A750 has mirror pre-fire, with a 2-second delay between the mirror up and the shutter releasing, which is good enough for many purposes, though not all.)
It all comes back to really having no clue why Sony made the feature decisions it did. Having a mirror/shutter mechanism that is capable of working at up to 5 or 7 fps requires a stronger and likely more expensive design than does a 2.5-3 fps mirror/shutter assembly. How much did the new sensor and processing engine cost to develop, and how much of that must be recouped in the sale of this camera? There are plenty of other questions one could ask. How much to develop the improved (slightly) viewfinder, or implement the manual focus live-view? And more.
In the end, folks can speculate all they want, but we don't and can't know the answer to why any camera is designed the way it is unless someone from Sony explains the actual decisions, and this is highly unlikely to ever occur. My own guess is that, for the most part, Sony eliminated features that it believes appeal to a smaller minority of photographers, and particularly not those to whom the product is targeted.
However, this still would not explain the omission of program shift in my mind, because it has been in just about every camera that came before, and because the work-around requires a more extensive understanding of photography (i.e., shooting in A mode or S mode) than the seeming target consumer may have. It could be that it's omission was as much an oversight that nobody caught until it was too late as an intentional product design decision, and that like the dead meter in the Maxxum 7D when flash is used, it's a hard-wired operating characteristic that can't be "fixed" by a firmware upgrade. Remember, that's just a guess.
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Mark Van Bergh
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