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05-27-2015, 10:16 AM - 1 Like   #511
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QuoteOriginally posted by thibs Quote
thanks banep. Do you have full patent references?
Might be interesting to try to decipher it.

Thanks
Patent No.2015-87404 by Ricoh, Japan


Last edited by banep; 05-27-2015 at 10:27 AM.
05-27-2015, 11:12 AM   #512
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Looks like a real SLT !
Plus a real surprise to see lenses btw "mirror" and sensor !

Last edited by Zygonyx; 05-27-2015 at 11:18 AM.
05-27-2015, 11:20 AM   #513
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Something about a concave second mirror that reflects a projection to the AF sensor via the main mirror. Was the lens always there above the AF sensor? Definitely not SLT. It has a OVF.
05-27-2015, 11:36 AM - 1 Like   #514
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QuoteOriginally posted by Zygonyx Quote
Looks like a real SLT !
Except, of course, the quarter wave plate (14) and the sub mirror (15) are all moved out of the optical path along with the main mirror (11) during an exposure.

Here's a link to a machine translation into English, straight from the Japanese Patent Office.

I have only briefly reviewed it, so please forgive any oversimplification or errors, but it appears the primary function of the concave sub mirror is to eliminate the need for a condensing lens at the entrance to the AF module (18). This may indeed allow a larger (wider, relative to the image) AF module to be used in a tighter space, though I'm not sure how they would deal with aberration around the edges.

It appears the quarter wave plate is used to manipulate the polarization of light bouncing around in the AF system, so that less light is lost between the main mirror and the AF module while still permitting good viewfinder brightness.

05-27-2015, 01:53 PM   #515
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Sounds great - in the patent.
Hopefully it works in an actual product.

It's a bit risky jumping right ahead with something so new, in a flagship like the new FF particularly. New tech always has glitches, after being exposed to real world usage.
05-27-2015, 04:15 PM   #516
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Could this really be in the new FF,as it must be already out being tested now, if release is later this fall....maybe in future models,then the new zooms will really kick AF
05-27-2015, 05:11 PM   #517
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QuoteOriginally posted by Shanti Quote
Could this really be in the new FF
The patent was lodged in 2013 in Japan, and mentions a full-size sensor (which is what I believe it has been optimised for).

So it is likely that they were working on it from even before 2013. The patent itself may be a sign that they are confident they have something that actually works.

Hence Ricoh have probably had a few years to refine the technology to manufacturing stage for their new FF. But the Ricoh boffins can only test it so far themselves in the lab. Once it hits the stores and gets into user's hands - and is forced to work with 10000 different types of old and new lenses, 10000 different lighting scenarios etc etc - will be the real test.
05-27-2015, 05:35 PM   #518
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I couldn't access the original patent (server overloaded) but from an earlier (horrible) translation it seems that the purpose of the concave mirror design is to allow spreading AF areas more across the frame, compared to the "crammed around the centre"-design that most FF cameras feature.

05-27-2015, 05:49 PM   #519
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QuoteOriginally posted by D1N0 Quote
Something about a concave second mirror that reflects a projection to the AF sensor via the main mirror. Was the lens always there above the AF sensor? Definitely not SLT. It has a OVF.
Doesn't all AF (D)SLR's work the same way?
The only difference seems to be the design of the second mirror in order for the AF points to cover a larger area of the frame. Hardly a new AF system but just tweaking to suit the format.
But I might have misunderstood something...
05-27-2015, 06:26 PM   #520
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QuoteOriginally posted by Pål Jensen Quote
just tweaking to suit the format.
I think so too. Kind of a cheap way to make the tight bunching of the K-3's 27-point AF array spread across a wider field of view. It saves them money by letting them re-use K-3 AF hardware parts better in the FF.

Only problem is, if they stick with the K-3 AF sensor, you will then have 27 AF points spead too wide on FF, with huge gaps in AF sensor coverage. They need to turn those 27 points into 54 on FF if they want a decent AF point density for FF - like the D750/D810's 51 points or the 5D3's 61.
05-27-2015, 07:10 PM   #521
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Maybe a dumb question,but why can't Ricoh/Pentax AF be as good as Nikon? as everything else is top quality on K3. If they can tweak the Sony sensor to get the most out of it,why is AF so difficult??
05-27-2015, 08:44 PM   #522
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QuoteOriginally posted by Shanti Quote
Maybe a dumb question,but why can't Ricoh/Pentax AF be as good as Nikon? as everything else is top quality on K3. If they can tweak the Sony sensor to get the most out of it,why is AF so difficult??
They can. And they already are. Some tests show the k-3 actually better and more consistent than the Nikon equivalent. For auto focus. Not, however, for tracking which is where the Nikon shines. But for regular focus on a fixed subject the k-3 is about as good as it gets. K-3 is slower to lock focus but more consistently achieved a correct focus. Speed of the auto focus is a combination of the lens, the AF hardware and the logic that drives it. Pentax has elected, either intentionally or because the hardware is not fast enough, to optimize for correct lock rather than fast lock.

Everyone "knows" Pentax is not as good as the other brands yet objective tests show otherwise. Except for tracking. They need to improve that area and they need lenses capable of keeping up. SDM does not make the grade.
05-27-2015, 09:32 PM   #523
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QuoteOriginally posted by jatrax Quote
They can. And they already are.
Very true. After about the K-5 II things really started to change, and the K-3 stepped things up even further.

The intelligent integration of the 86k RGB metering sensor with K-3 AF was a pro grade FF feature that some K-3 competitors (eg D7200) still don't have, and others (eg the 7D2) only introduced after the K-3 arrived. And the implementation of -3EV sensitivity AF in both the K-5 II and K-3 AF was a pioneering DSLR feature that some pro FF Canikons (eg 1Dx, 5D3, D4s, D810) still can't match.

So technologically, Ricoh has certainly been putting effort into AF. Now to evolve the AF software and hardware even further, and work on the lenses.
05-27-2015, 11:48 PM   #524
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QuoteOriginally posted by rawr Quote
Hence Ricoh have probably had a few years to refine the technology to manufacturing stage for their new FF. But the Ricoh boffins can only test it so far themselves in the lab. Once it hits the stores and gets into user's hands - and is forced to work with 10000 different types of old and new lenses, 10000 different lighting scenarios etc etc - will be the real test.
I would be very happy to help with the testing!

All they have to do is ship one to me. Now!
05-28-2015, 12:46 AM   #525
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QuoteOriginally posted by rawr Quote
Only problem is, if they stick with the K-3 AF sensor, you will then have 27 AF points spead too wide on FF, with huge gaps in AF sensor coverage. They need to turn those 27 points into 54 on FF if they want a decent AF point density for FF - like the D750/D810's 51 points or the 5D3's 61.
41 would be more correct if they reuse the K-3 AF sensor... (27 x 1.5 crop)
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