Originally Posted by
arthurking83
a hybrid system using both OVF and an EVF as an overlay is easily possible(or in theory should be) .. as pellicle mirror cameras have been around for a long time.
Sony themselves used the system for a while on some SLT type cameras ... fixed mirror cameras but using evf.
The purpose of the hybrid is to allow an OVF for those times when one is needed(eg. low battery power) or EVF when that's the better option .. not really the more difficult option of both at the same time, although that would be a great option too and possible via a secondary (eg. focus) sensor or something.
The reason I mentions a nearly 10 year or beyond time frame is simply for the uppermost end of the DSLR spectrum. Nikon's historical camera model frequency has repeated yet again and has consistently been consistent from D1 to D2 .. to D5 now. There's no reason to expect any change in that process, and their choices are probably business related more so than any need to advancing technology.
I don't know about Canon, but it's easy to speculate on the top end Nikon being DSLR for at least about 10 years or so. In the impending period of 8-10 years time from now, when the next gen model is due .. it's anyone's guess tho.
*** Actually scratch all that .. my bad. The updating of D(single digit) series cameras is about 4 years or so .. every Olympics .. again my bad .. so 5 years time is reasonable to expect a seachange in DSLR viewfinder tech .. not 8-10 years as I mistakenly first counted(sorry 'bout that).
And I keep reading that mirrorless cameras have a weight saving advantage in that the heavy mirror can be done away with .. and I doubt that the mirror of the D70s weighs in any more than about 50g or so .. and at a guess(until I can pull the old one apart .. which I will) .. the entire unit of stainless steel mount, screw drive AF motor, dioptre, shutter unit many electronic paraphernalia all weigh in at a measly 110g all told. I can feel that most of that weight is at the front of the camera being the lens mount and AF drive motor.
Anyhow, the mirror itself is always best having as low weight as possible and hence made from the lightest(strongest) material available .. as it's weight impacts the camera's operation too.
Like Lance said, size is, or should be a non issue .. mainly for lens compatibility.
Shorter backfocus designs do allow for smaller short focal length lenses tho .. this is proven, but then the issue of corner darkening comes into play too. As the lens gets closer to the sensor plane it gets increasingly harder to evenly light the sensor .. ie. vignetting.
I'm not a fan of all this in camera processing to remove such aberrations, and would prefer to see that done at the source too. I'm not a fan of Sony's(and Olympus') methods on that front.
KISS!
I think a lot has been lost in this thread and some heated replies came about from that loss in translation too.
Steve asked the question .. "Why don't they"
I simply replied with what I thought seemed an appropriate, and hopefully sensible answer, or explanation as to why they don't.
the way I'm seeing it is that the mirrorless systems still have a bit to do to become true replacements for OVFs irrespective of whether some users proclaim them as the bee's knees.
Obviously not according all tho(well, there's at least two of us here and I know of a few more) .. and there's the important point.
As a manufacturer that is very heavily reliant on customer loyalty and repeated business, they can't afford to alienate any of these customers.
(and it totally has me stumped why their customer service levels are non existent too in these hard times for them!)
Change the good(OVF) for good(EVF) and introduce some deficiencies while not really adding to the system significantly .. sounds like a recipe for disaster on a business level.
The EVF needs to be exceptional .. not just good!
So the reason of why not is simple, yet a complex mix of:
no real benefit to the average punter, who doesn't really care or know any different.
no real ROI on the necessary re-engineering effort, bring the cost of some (unknown)sticky point in the EVF chain down and for sure well see them in at the low end DSLR market.
biggest issue is obviously the power requirements. This needs to be addressed urgently for the systems to make it into the high end pro market.
Funny thing is, if they could implement that system of the AF sensor acting as a pseudo EVF system, power needs could be reduced a fair amount.
I'm sure the power needs of the main sensor are mainly to blame for the power hungry nature of EVF cameras.
The smaller, lower res, EVF sensor for an OVF-EVF overlay system ... would use less power than a current EVF system and is optionally turned off and OVF is simply used.
I reckon the question should be more along the lines of .. why would you jump in now? .. when so many more options are available 'in the future'.