The DSLR's AF innovation might be showing on Photokina 2010?

Started Aug 2, 2010 | Discussions
PeterZheng
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The DSLR's AF innovation might be showing on Photokina 2010?
Aug 2, 2010

The DSLR's AF innovation might be showing on Photokina 2010? by PeterZheng

The phase difference detection method has successfully been achieved a built-in way on a DC image sensor, and some the products are already applied on the market.

I think that a hereditary DSLR AF optical path's method will be rewrote, a hereditary way is a sub-mirror added to a master-mirror's backside, that is source from the Pentax's patent (registered in 1973-1979), Pentax ME-F was a first applied example, released 1980 and sold into market 1981. (Today's a master-mirror way is still a faraway origin from the Pentax's patent in 1956. In nowadays, an optical viewfinder is still needed.)

nowadays a prevalent Phase Detection System is like this:

Phase detection is achieved by dividing the incoming light into pairs of images and comparing them. SIR TTL passive phase detection (secondary image registration, through the lens) is often used in film and digital SLR cameras.
http://www.vistaview360.com/photography/autofocus.htm

In the early period, another Phase Detection System was Honeywell's TCL detector module at 1981, the TCL detector's developmental aim was mainly for the weapon system range finder, and that period was the semiconductor technology of confined, its spacing is 200μm between the pixels, so in the camera industry that quickly it was eliminated out, that was just shortly term 1984-1986 within the camera industry, and then the AF system walks to the SIR TTL phase detection method. In currently, the DC image sensor 1-μm spacing pixels, the DSLR image sensor is 4-6 μm spacing pixels.

In FSLR camera, a sub-mirror method is requisite as an AF system, but the DSLR camera uses an image sensor and not the films, so that the AF sensor is possible to take a built-in way within an image sensor, then a sub-mirror method is no longer needed.

cancels a sub-mirror would win the many advancement, and DSLR's cost would obtain reduced, reducing the number of parts, reducing the adjustment items at the production process, the optical path related AF-error would obviously be improved. There is also another important point at the future DSLR, -------- AF points are possibly distributed in a larger space compares to the sub-mirror method. In the live-view mode, the phase difference detection method became an available way, and AF will be no longer slowed over there.

Since 2007 later, related the phase detection range finder method will take a built-in way within an image sensor, Nikon has nearly 20 publication patents, Canon has nearly 25 publication patents, Sony has nearly 15 publication patents, and Panasonic also has a few of patents. However, Pentax is no patent in this one side.

Nikon, Publication JP 2010129783, Date: 2010-06-10
http://patent.astamuse.com/ja/published/JP/No/2010129783/&#35443

Sony, Publication JP 2010-78707 (P2010-78707A) Date: 2010-04-08

http://www.ekouhou.net/%E6%92%AE%E5%83%8F%E7%B4%A0%E5%AD%90%E3%81%8A%E3%82%88%E3%81%B3%E6%92%AE%E5%83%8F%E8%A3%85%E7%BD%AE/disp-A,2010-78707.html

Canon, Publication US2010165176 (A1) Publication date: 2010-07-01

http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=1&f=G&l=50&d=PG01&p=1&S1=20100165176&OS=20100165176&RS=20100165176

And, Nikon is also to continue improving the hereditary phase detection's range finder technology, they are full steam to improve the AF performance, some newer patents get showed. Nikon usually is taking a safer policy.

Looks like that Canon might be shortly outright to give up the traditional components for the phase detection range finder.

The DSLR's AF innovation might be showing on Photokina 2010?

PeterZheng
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Re: The DSLR's AF innovation might be showing on Photokina 2010?
In reply to PeterZheng, Aug 2, 2010

Nikon, Publication JP 2010129783, Date: 2010-06-10

(Unicode UTF-8)
http://patent.astamuse.com/ja/published/JP/No/2010129783/ 詳細

or

(ISO)
http://patent.astamuse.com/ja/published/JP/No/2010129783

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ZorSy
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Re: The DSLR's AF innovation might be showing on Photokina 2010?
In reply to PeterZheng, Aug 2, 2010

Of course with the development of mirror-less systems it is obvious they all have one thing in common - slow contrast detect AF compared to traditional phase detection system used in DSLRs. I can only guess all 3 or 4 links are about the same as the English version and yet again it all boils down to.....

[0011]However, the above-described known art has the following drawbacks.

...... As a result, at the location where the focus detection pixels are disposed the pixel information is lost, or, because it has a large error if used as image information, it is necessary to interpolate from the adjacent image sensing pixels to generate the image signal......

hmm, it would acquire focus quicker than contrast detect system but for full resolution would have too again black-out CMOS/CCD to read out all piixels. Or interpolate "AF" pixels...

Other drawbacks are interesting too. So work is in progress , that is a positive sign.

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TrapperJohn
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Then, there's CDAF
In reply to PeterZheng, Aug 2, 2010

PDAF has been around for a while - arguably dating back to manual PD on the first rangefinders.

CDAF, on the other hand is in its infancy, and has come a long way in just a few years. I've been using a high quality CDAF enabled lens: the Pana/Leica 25 1.4, on a CDAF body, the Olympus EP1. Focus is accurate and remarkably fast, just a bit slower than the same lens on a PDAF E3. And that's just after a few years of development. If you're thinking of CDAF in terms of what cheap P&S's were doing a couple of years ago - think again. It can be very fast.

In the end, the system will be driven by cost. PDAF requires sampling the projected image from two distinct perspectives to get the phase shift. CDAF works on a single image, or any portion of the image, with no additional sensors or mirrors. A lot cheaper to build, especially as there are no complex alignment issues.

So it won't be a matter of which one is the fastest, it will be which one is fast enough for most people, and costs the least.

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Joseph S Wisniewski
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Patents don't imply launch or demo dates...
In reply to PeterZheng, Aug 2, 2010

PeterZheng wrote:

The DSLR's AF innovation might be showing on Photokina 2010?

Or it might not.

But the patents mean nothing, one way or the other.

You make an enormous leap, from Nikon, Canon, and Sony having filed patents (which does not require a specific launch date) to having a very specific date, Photokina, with no logic or sources to connect the two.

I can point you to pages of Nikon, Canon, etc. patents that never reached the market.

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Joseph S Wisniewski
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CDAF not "in its infancy"...
In reply to TrapperJohn, Aug 2, 2010

TrapperJohn wrote:

PDAF has been around for a while - arguably dating back to manual PD on the first rangefinders.

And "manual CDAF" goes back to the first ground glass focusing on cameras, or to the camera obscura.

CDAF, on the other hand is in its infancy,

Well, if you count three decades of camcorders and two decades of point and shoot cameras as "infancy", sure.

and has come a long way in just a few years. I've been using a high quality CDAF enabled lens: the Pana/Leica 25 1.4,

The "CDAF enabled lens" is just an interchangeable version of what P&S camera have had for nearly two decades, fast, direct control of the focus motor, instead of very slow AF protocols devised 25 years ago for four bit processors embedded in the lenses of the day.

on a CDAF body, the Olympus EP1. Focus is accurate and remarkably fast, just a bit slower than the same lens on a PDAF E3.

The scary thing about CDAF is that it's not "just" CDAF, it's also an image recognition problem.

If you can look at a blurry tan colored blob on a blurry green background, you can say "hey, that might be a face". Then you can estimate how big the tan blob is, what focal length the zoom is at, and say "that might be a face at 8 feet, and the lens is currently focused at four feet, let's focus outward a bit".

Image recognition problems improve in speed in direct proportion to processor speed improvements. That's why everything that uses CDAF has been improving so dramatically the last few years.

And that's just after a few years

Decades

of development. If you're thinking of CDAF in terms of what cheap P&S's were doing a couple of years ago - think again. It can be very fast.

In the end, the system will be driven by cost. PDAF requires sampling the projected image from two distinct perspectives to get the phase shift. CDAF works on a single image, or any portion of the image, with no additional sensors or mirrors. A lot cheaper to build, especially as there are no complex alignment issues.

And that's the beauty of the systems that integrate PD AF on the main sensor, like the one that Fuji just launched.

So it won't be a matter of which one is the fastest, it will be which one is fast enough for most people, and costs the least.

Exactly.

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PeterZheng
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Re: a DSLR camera would provide AF of dual mode to be available
In reply to TrapperJohn, Aug 2, 2010

In future, a DSLR camera would provide AF of dual mode to be available, PDAF/CDAF mode is choice by user.

Secondly, CDAF not 'a few years of development'. The FSLR camera optical path method is this, a sub-mirror added to a master-mirror's backside, that is source from the Pentax's patent (registered in 1973-1979), Pentax ME-F was a first applied example, released 1980 and sold into market 1981. Pentax ME-F was applied CDAF way, Canon's T80 was also the CDAF way in 1985, but in same year Minolta has published a very famed α7000, it is PDAF system, as the second PDAF camera of Minolta. After two years, Canon FD mount lenses and cameras got discontinued. (X600 is Minolta's an initial PDAF FSLR camera in 1984).

Also, nearly all the DC cameras were applied CDAF way after 1990.
-

PS. For the patents would be related to the market, the above Pentax ME-F is example.

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