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Author Topic: 'Revolutionary' Dual Pixel AF Explained  (Read 11656 times)

sandymandy

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #15 on: July 26, 2013, 02:38:18 PM »
Am i the only one who prefers shooting with the optical viewfinder, even if live view is tzhe same speed? I think its not long anymore til Canon only releases only mirrorless cameras if the AF speed is the same. And then people like me can pay another 899$ or whatever for an electronic viewfinder :(

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #15 on: July 26, 2013, 02:38:18 PM »

photonius

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #16 on: July 26, 2013, 02:56:28 PM »
The supported lens box has some very disconcerting information.  I'm wondering about 3rd party lenses that should work but will be in contrast-detect just because they aren't "supported".  Also, what's the point of having this function work at f/11 if it doesn't work with teleconverters?  Who has a "supported" bare f/11 lens?

As pointed out, each lens has to be calibrated. based on the report, it seems they did an algorithm that can cover all lenses. However, there is absolutely nothing against have specific look-up tables for lenses that don't fit the normal algorithm. So, in theory there is nothing wrong with Canon providing firmware updates to include additional lenses. This could also include a separate set of algorithms for say the current 103 lenses attached to the 1.4x teleconverter. After all, it's just a matter of testing all lenses, teleconverter combinations, and develop the correct algorithms. Then load it into the camera body, provided the memory is large enough to hold all info.

As to third party lenses. In the case of sigma, they work already by pretending to be Canon lenses. At least in Sigma's case with their new lenses and the dock for updates, they might be able to make it work. I.e. first, they have to choose a lens in the the 103 line-up, then they have to check that the algorithm works. If not select another lens. Amongst the 103, hopefully they find one that with some firmware update works.

3kramd5

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #17 on: July 26, 2013, 02:59:27 PM »
If the entire sensor is capable of phase detect, why are there still discrete autofocus points? What keeps them from using a touch screen to say "focus here"?

I believe they demoed exactly that in some of the 70D promo videos.

Cool - haven't seen them.

The phase detect on the sensor only works with the mirror up, and is seamless across the image. With the mirror down, using the viewfinder, you're still using the "old" phase detect system, which still requires the discrete points.

Ah, yes that makes sense. The ability to (auto)focus anywhere on the frame is pretty revolutionary indeed.

Am i the only one who prefers shooting with the optical viewfinder, even if live view is tzhe same speed?

I've never used a system where your "even if" is true, but if one were available I wouldn't mind EVF. I'd rather hold the camera up to my eye than cantilevered in front of my face. In other words, given the "even if," I'd prefer OVF to back mounted LCD in most cases.
« Last Edit: July 26, 2013, 03:01:54 PM by 3kramd5 »
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unfocused

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #18 on: July 26, 2013, 03:33:06 PM »
Am i the only one who prefers shooting with the optical viewfinder, even if live view is tzhe same speed? I think its not long anymore til Canon only releases only mirrorless cameras if the AF speed is the same. And then people like me can pay another 899$ or whatever for an electronic viewfinder :(

No, you are not the only one. But, I am increasingly thinking I am more of a dinosaur than I realize (But then again, that happens every time I look in the mirror anyway).

I get that Canon is trying to make live view as useful and accurate as an optical viewfinder, but I hope they don't start to compromise optical viewfinder performance. Sorry, but I just don't see how live view can ever compete with the ergonomics of a viewfinder especially with longer lenses and in bright light.

This seems to me to be another sign of the convergence of video and stills and I suspect that stills photographers are just going to have to learn to accept some compromises as video starts to rule the world.
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Joellll

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #19 on: July 26, 2013, 03:41:05 PM »
So let me get this straight....

What the Dual Pixel AF is doing, is that the sensor is actually a two 20mp sensor that is adjacent to each other in a way that it is detecting parallax from the slightest difference between the two pixels?

If that is the case, isn't it actually easier for macro lenses to focus? Since the closer an object is, the parallax effect is more apparent, giving the sensor more difference to detect.

hgraf

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #20 on: July 26, 2013, 03:41:58 PM »
Perhaps 3rd party lenses wont have a problem after all, here is a preview of a 70d with a 18-35 sigma performing splendidly apparently:


3rd party lenses in a way "pretend" to be real Canon lenses in certain areas.

Depending on how much Canon "checks" what kind of lens is attached, and as long as the lens your lens is pretending to be is supported it should work without issue.

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dstppy

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #21 on: July 26, 2013, 04:00:45 PM »
Am i the only one who prefers shooting with the optical viewfinder, even if live view is tzhe same speed? I think its not long anymore til Canon only releases only mirrorless cameras if the AF speed is the same. And then people like me can pay another 899$ or whatever for an electronic viewfinder :(

I think we'll start seeing them, but mirrored cameras are going to be around for a while still.

It's going to have to be FLAWLESS for them to not completely get ravaged if they switch anything mid-prosumer . . . and even still, how much complaining about the 5D3 & 1Dx did we have to listen to?  No, I think we're safe for now.
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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #21 on: July 26, 2013, 04:00:45 PM »

gruhl28

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #22 on: July 26, 2013, 04:14:59 PM »
The supported lens box has some very disconcerting information.  I'm wondering about 3rd party lenses that should work but will be in contrast-detect just because they aren't "supported".  Also, what's the point of having this function work at f/11 if it doesn't work with teleconverters?  Who has a "supported" bare f/11 lens?

I'm concerned about the 100mm f/2.8 Macro (non-IS), which I own. This is a currently sold lens, and the document said that dual pixel would support all current lenses, but the macro is on the list of lenses that are not fully supported. This seems like a contradiction. This is the only high quality current lens that I noticed on the list that is not fully supported.

FYI, I pinged Canon USA about this, and they say that they do not have information yet about which lenses are compatible, despite the fact that Canon Europe has a list up on their website of lenses that are not fully compatible.

jrista

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #23 on: July 26, 2013, 04:24:51 PM »
The supported lens box has some very disconcerting information.  I'm wondering about 3rd party lenses that should work but will be in contrast-detect just because they aren't "supported".  Also, what's the point of having this function work at f/11 if it doesn't work with teleconverters?  Who has a "supported" bare f/11 lens?

If you are shooting a movie, and stop down to f/11, it will still support phase-detect AF. It is the stopped-down (current) aperture that matters in this case, not the maximum aperture.

I can't say why it wouldn't work with a TC, especially if the max aperture was larger than f/11...
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LetTheRightLensIn

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #24 on: July 26, 2013, 04:44:28 PM »
The supported lens box has some very disconcerting information.  I'm wondering about 3rd party lenses that should work but will be in contrast-detect just because they aren't "supported".  Also, what's the point of having this function work at f/11 if it doesn't work with teleconverters?  Who has a "supported" bare f/11 lens?

Oh darn, it doesn't work with TC combos?? So the poor 70-300L+1.4x TC will STILL not be able to focus?? :(
And yeah what gives f/11 other maybe some weird old bizarro tele-tube lens or mirror lens from long ago? Do those things even have AF??

EDIT: oops forgot that for movies you do stopped down shooting as jrista points out so of course f/11 AF would be a commonplace need. In fact even beyond f/11 would be nice.

But I sure hope that for once they don't forget the 70-300L+1.4x TC III combo for AF.
« Last Edit: July 26, 2013, 05:16:52 PM by LetTheRightLensIn »

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #25 on: July 26, 2013, 04:46:44 PM »
The supported lens box has some very disconcerting information.  I'm wondering about 3rd party lenses that should work but will be in contrast-detect just because they aren't "supported".  Also, what's the point of having this function work at f/11 if it doesn't work with teleconverters?  Who has a "supported" bare f/11 lens?

Oh darn, it doesn't work with TC combos?? So the poor 70-300L+1.4x TC will STILL not be able to focus?? :(
And yeah what gives f/11 other maybe some weird old bizarro tele-tube lens or mirror lens from long ago? Do those things even have AF??

LOL. I guess people don't quite get live view AF. The f/11 is for the current, selected, stopped-down aperture, not the maximum aperture. If you are shooting a video, and stop down for DOF, the at-sensor PDAF will continue to work.

Unless there is actually some lens checking going on, I suspect it would work with a lens+TC so long as the selected aperture does not drop below f/11. I can't imagine them tying the dual-pixel AF feature to specific lenses (the PDF did say it would work with some older lenses). I think the listing is jut what they have officially tested.
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LetTheRightLensIn

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #26 on: July 26, 2013, 05:10:24 PM »
The supported lens box has some very disconcerting information.  I'm wondering about 3rd party lenses that should work but will be in contrast-detect just because they aren't "supported".  Also, what's the point of having this function work at f/11 if it doesn't work with teleconverters?  Who has a "supported" bare f/11 lens?


Perhaps 3rd party lenses wont have a problem after all, here is a preview of a 70d with a 18-35 sigma performing splendidly apparently:

Canon 70D Review + Sigma 18-35mm f1.8 lens preview


That does look pretty cool. It sure appears to work vastly better. If they could just fix up low ISO DR, I wouldn't even begin to think of Nikon since they have so much better video, liveview, video af, UI, nicer set of lenses, etc.


LetTheRightLensIn

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #27 on: July 26, 2013, 05:14:28 PM »

I've never used a system where your "even if" is true, but if one were available I wouldn't mind EVF. I'd rather hold the camera up to my eye than cantilevered in front of my face. In other words, given the "even if," I'd prefer OVF to back mounted LCD in most cases.

Once cheap way to get that eye-level viewing back is to just attack a Hoodman type viewer to the LCD.

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #27 on: July 26, 2013, 05:14:28 PM »

LetTheRightLensIn

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #28 on: July 26, 2013, 05:17:51 PM »
The supported lens box has some very disconcerting information.  I'm wondering about 3rd party lenses that should work but will be in contrast-detect just because they aren't "supported".  Also, what's the point of having this function work at f/11 if it doesn't work with teleconverters?  Who has a "supported" bare f/11 lens?

Oh darn, it doesn't work with TC combos?? So the poor 70-300L+1.4x TC will STILL not be able to focus?? :(
And yeah what gives f/11 other maybe some weird old bizarro tele-tube lens or mirror lens from long ago? Do those things even have AF??

LOL. I guess people don't quite get live view AF. The f/11 is for the current, selected, stopped-down aperture, not the maximum aperture. If you are shooting a video, and stop down for DOF, the at-sensor PDAF will continue to work.

Unless there is actually some lens checking going on, I suspect it would work with a lens+TC so long as the selected aperture does not drop below f/11. I can't imagine them tying the dual-pixel AF feature to specific lenses (the PDF did say it would work with some older lenses). I think the listing is jut what they have officially tested.

hah yeah, forgot of course video is stopped down shooting  ;D so yeah f/11 would be a pretty common place thing with any lens in this case

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #29 on: July 26, 2013, 05:24:02 PM »
I'm concerned about the 100mm f/2.8 Macro (non-IS), which I own. This is a currently sold lens, and the document said that dual pixel would support all current lenses, but the macro is on the list of lenses that are not fully supported. This seems like a contradiction. This is the only high quality current lens that I noticed on the list that is not fully supported.

If the lens on that list has USM, it says USM. The 100/2.8 Macro is listed as EF100mm f/2.8 Macro, with no USM mentioned. So it looks like its this 100mm macro which is not fully compatible:

http://www.canon.com/camera-museum/camera/lens/ef/data/macro/ef_100_28macro.html

The current non-L 100mm macro should be fine:

Quote from: Canon
All of Canon’s current range of EF and EF-S lenses are compatible with the Dual Pixel CMOS AF system.
5D II | 24-70 II | 70-200 II | 100L | 40 | Sigma 50/1.4 | 40D | 10-22 | 17-55 | 580 EX II | 1.4x TC II

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Re: 'Revolutionary' Dual Pixel AF Explained
« Reply #29 on: July 26, 2013, 05:24:02 PM »