Re: Why didn't Pentax....

[Peter J. Alling]

The dust "hanging" in the light path between the sensor and the lens 
would be considerably more of a problem than dust on the lens.  The 
closer to the focal plain it gets the bigger the problem is.  The only 
advantage to this I see is that the glass would be easier to clean and 
less fragile than the anti-aliasing filter or the sensor.

Steve Jolly wrote:
Peter J. Alling wrote:
The semi silvered mirror would collect dust, and they're fairly fragile.

Thinking about it, dust on the semi-silvered mirror would be far less 
of a problem than dust on the sensor for the same reason that dusty 
lenses are rarely something to get worked up about - the dust isn't at 
the focal plane.  Which makes me wonder if DSLR manufacturers couldn't 
all-but-eliminate the problem of sensor dust by putting in a piece of 
flat multi-coated glass (maybe even ED glass) between the mirror and 
the sensor's anti-aliasing filter.  You could even make it as easy to 
change as a focussing screen. :-)

S


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During a war you get to drive tanks through the sides of buildings 
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