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05-14-2015, 12:31 PM   #16
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Unless I have misunderstood, the description also seems to be suggesting that the system improves low-light sensitivity somehow, utilising polarized light. No idea how that works.

The rest of it seems a bit clearer. The secondary mirror reflects light back to the rear of the primary mirror, and then down to the AF sensor, rather than reflecting it directly to the AF sensor. This allows the secondary mirror to be vertical rather than at an angle, which in turn allows it to be bigger because increasing the size does not extend it towards the shutter. I presume that the concavity of this mirror stops the spreading of light rays so that when they reach the floor of the mirror box they are still within a smallish area, despite the increased size of the mirror.

05-14-2015, 01:08 PM   #17
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And suddenly, Ricoh works a miracle to make pentax af better than either canon or nikon...

if only
05-14-2015, 05:25 PM   #18
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QuoteOriginally posted by Fogel70 Quote
the secondary mirror is concave
Would managing the very angled spead of light this type of uneven mirror reflects cause any issues for the AF sensors? Greater risk of chromatic aberration in light reflected from the far angles of the mirror into the AF sensors, perhaps?

The math is too complicated for me, but this article illustrates why reflective divergence in concave mirrors could cause some headaches for their use in AF.

Last edited by rawr; 05-14-2015 at 05:36 PM.
12-14-2015, 04:20 PM   #19
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Probability this'll be on the FF K-1??

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