New Sensor Tech in EOS 7D Mark II [CR2]

[jrista]

Right.
What would be really cool to see is some sort of hardware level binning process that maintains the integrity of the RAW file.

Half the reason I'm so anxious for super high resolution cameras is that I haven't been terribly impressed with the image quality off my 5D2. That nasty AA filter (which I'm pretty sure is especially bad on the 5D2) effectively cuts resolution in half. When I first saw my pictures on a decent 4MP monitor I was amazed at how little detail loss there was vs. looking at the image zoomed to 100%. My bet is that a good 4K (8MP) monitor is going to display your images with just as much detail as a high quality print... Because the detail actually isn't there in the first place.

One option is just quadrupling resolution and getting rid of the AA filter (which I'm actually fine with), but if they could bin the full per-pixel RGB signal on the sensor it should effectively deal with moire, and we get to keep our current file size, and it should produce an actual 20MP image instead of the blurred out fake we currently end up with.

The last thing I really want to see is the integration of clear microlenses. Even the heavily faded green pixels that we have right now still block a lot of light. Given how advanced interpolation is I doubt that eliminating the colour value for one of the pixels would have a significant impact on image quality.

Sorry, but that (bolded) is such a ludicrous, laughable comment, I'm just flabbergasted. An AA filter DOES NOT cut resolution "in half". That is blowing things SO FAR out of proportion it may be one of the most ludicrous things I've read on these forums. OLPFs, optical low pass filters, are designed to affect high frequencies only, and only around the nyquist limit at that. You lose a TINY amount of resolution...but it doesn't matter, because the "resolution" your losing just contains nonsense anyway. OLPFs blur very high frequency data that nearly or exactly matches the spatial frequency of the sensor's pixels just enough such that they the information doesn't alias. That's it. Aliased information is a REAL loss of information. Technically speaking, OLPFs PRESERVE information...they save information that can be saved, and discard information that cannot be correctly interpreted by the sensor anyway. On top of that, a very light application of unsharp masking can effectively reverse the blurring, and improve the resolution of that high frequency data, without actually bringing back all the nonsense.

Quadrupling resolution and removing the AA filter is only an option if your lenses cannot resolve that much detail. With the resolving power of Canon's current lens lineup at faster apertures, I'm not so sure that cutting pixels into quarters is actually enough to avoid any kind of aliasing. At narrower apertures, like f/8, diffraction already blurs information enough that it can't alias, but that's a really narrow aperture for a lot of work, not everyone uses it. There are very few applications where removal of an AA filter will not cause aliasing of some kind, and pretty much anything artificial is going to have repeating patterns that, depending on distance to camera, can create interference patterns (moire).

This whole "Remove the AA filter" craze is just that...a craze. It's a "thing" Nikon started doing to be different, to get some "wows", and maybe bring in some more customers. Ironically, given that removal of an AA filter is really NOT a good thing...it's worked. Nikon's marketing tactics have sucked in a whole lot of gullibles who don't really know what an AA filter does or how it works, or how to work WITH it, and now we have a whole army of "photographers" who want AA filters removed from all cameras. Personally, I REALLY, TRULY, HONESTLY DO NOT want Canon to remove the AA filter. It is NECESSARY, it PRESERVES preservable data and eliminates useless data, and I LIKE THAT.

And anything that is lost? It's MINIMAL. In the grand scheme of how much resolution you have...you maybe lose a percent or two of really high frequency information...but you really don't have that information anyway because it is similar in frequency to noise...so again, moot.

Given that the filter makes it physically impossible to have a repeating pattern of stripes the same frequency as the pixel grid, so that you cannot have a perfect transition of black pixels to white, I'd say that is cutting resolution in half. That is, compared to some magical thing that accurately reads the full RGB spectrum on each pixel.

You are right about the necessity of the AA filter though.
I was thinking that if the interpolation algorithm only sampled each pixel within a specific cluster of four pixels and not every pixel around it that it would solve the moire problem. Really that would just give you different colour banding instead.
Now, if we added a second layer of microlenses on top of the first to direct light only at individual groups of pixels, that would guarantee the full RGB read on each cluster, and allow hard transitions...

On second thought I guess that sounds a little excessive just to gain the ability to have large pixels with a hard transition instead of twice as many pixels with a row of grey pixels that's half as big. You can bin the smaller pixels with a normal AA filter just the same, we just need a way of doing that without destroying the flexibility of RAW (otherwise I assume people would have been using compressed formats a long time ago).

I think your conflating the CFA with the AA filter. The CFA, color filter array, is what produces the RGBG pixel pattern. That is ENTIRELY different than the AA filter, which does optical blurring only at high spatial frequencies near the spatial frequency of the sensor pixels.

The CFA doesn't cut resolution in half either. It has a minor impact on luminance resolution, it's mostly color resolution that is affected by the CFA. But since we pick up detail primarily due to luminance, a bayer sensor doesn't lose anywhere remotely close to as much resolution as Sigma would have you believe with their Foveon marketing, for example. The luminance resolution, the detail resolution, of a bayer still trounces anything else. It's your color fidelity and color resolution that suffers. Were not as sensitive to color spatial resolution as we are to luminance though, expecially when the luminance is combined. (It's actually a pretty standard practice in astrophotography to generate an artificial luminance channel, blur the RGB channel a bit (which practically eliminates noise and actually improves color fidelity a bit by reducing color noise), process the luminance channel for detail, then combine the L with the blurred RGB. The end result is a highly detailed image that has great color fidelity.)

As for the double layer of microlenses...sure, you could read a full RGBG 2x2 pixel "quad" and have "full color resolution". Problem is, that LITERALLY halves your luminance spatial resolution...so you actually don't gain squat from a resolution standpoint by doing that. Doing that, you would lose significantly more resolution than either the CFA or the AA filter cost you...both of which are trivial in comparison do doing what your asking for. BTW, what your describing is called super-pixel debayering. That, too, is a common option in astrophotography image stacking...instead of basic or AHD debayering, you usually have the option to either super-pixel debayer, or "drizzle" (which, if you have enough subs...such as a couple hundred...is a means of achieving superresolution, and can increase your output image resolution by two to three fold.) You don't even need another microlens layer to do super-pixel debayering...you could use a tool like Iris or maybe even DarkTable/RawThearapy, to do it on any image you want.

Finally, even if you do super-pixel debayering, your not going to ever have "hard edges". Statistically speaking, the chances if a white/black line pattern you wish to photograph perfectly lining up with your pixels, regardless of how large or small they are, is so excessively remote that it is statistically impossible. Not in any real-world situation. You might be able to build some kind of contraption and AI software to eventually achieve it, but that is well beyond the realm of practicality. If you remove the AA filter, use super-pixel debayering, you might have larger pixels with full color fidelity...but your going to have a massive amount of aliasing. Those white and black lines would have some nasty stair-stepped edges, they would just look atrocious.

 

[Radjan]

What do you all think are the chances, that the 7D II will surpass the 5D mark iii/1DX on certain things? Such as IQ, ISO, DR or other things?

I know it's a crop sensor, so it is obviously limited, compared to FF.

And I must say - it's brilliant reading all you folks replies, you all have some serious knowledge about the technology us mere mortals are toying with ;D

 

[Lee Jay]

Further, for everyone else who continues to perpetrate the myth that somehow the two halves of the pixels, which are under not only one microlens, but also under one color filter block, could somehow magically be used to expand dynamic range "for free" are fooling themselves, and anyone who listens to them. Magic lantern either uses two FULL sensor reads (vs. half sensor reads), or they do line interpolation for half the resolution, to achieve their dynamic range. There is no free increase to dynamic range, and DPAF isn't going to somehow allow more dynamic range for free. The problem with the idea of using one half of the AF photodiodes for an ISO 100 read, and the other half for an ISO 800 read, is that is HALF the light! That is not the same as what ML does, which involves the FULL quantity of light, or else half the light AND half the resolution.

Huh? Please explain how reading both halves at the same gain gets you all the light but reading them at different gains gets you only half the light? How different do the gains have to be to cut the light in half? Is 1% enough?

What you said makes no sense to me.

The photodiodes are SPLIT. Each half gets half the light coming through the lens. It doesn't matter what ISO you read them at...if you read "half"...it's half the light. So your reading half the light at ISO 100, and half the light at ISO 800...well, you really aren't gaining anything. The only way to increase dynamic range by any meaningful amount is to either gather MORE light IN TOTAL...or reduce read noise by a significant degree (i.e. drop it from ~35e- to 3e-). Assuming it ever even becomes possible to read the photodiodes for image purposes like that, you might gain an extremely marginal improvement...but overall, there really isn't any point. It isn't the same as what ML is doing. They are either reading alternate lines of the sensor at two different ISOs, then combining them at HALF THE RESOLUTION, or they are doing two full reads of the sensor. Either way, for the given output size, they double the quantity of light. Reading two HALVES of a SPLIT photodiode gets you...ONE full quantity of light.

You're making no sense.

In all these cases, you're getting the same amount of light because you're starting with the same exposure. The point of reading the halves at different ISOs is to reduce read noise without causing clipping. One side ensures you get the highlights on bright pixels tthe other gives you dramatically reduced read noise on dark pixels. When you combine them, you've effectively increased real bit depth/DR.

Of course, if the halves could both be read out at dramatically lower noise that would be even better, but this is one way to achieve that without having an improved read noise behavior. Canon sensors have dramatically reduced read noise at high ISO, the only issue being saturation.

 

[Loswr]

What do you all think are the chances, that the 7D II will surpass the 5D mark iii/1DX on certain things? Such as IQ, ISO, DR or other things?

The 7DII will surpass the 5DIII/1D X in viewfinder magnification, and the 5DIII in frame rate...that's pretty much it.

 

[Loswr]

What you said makes no sense to me.

You're making no sense.

Your first statement is acceptable, your second statement is wrong. The explanation is true and correct, in spite of your apparent inability to comprehend it.

 

[bdunbar79]

Further, for everyone else who continues to perpetrate the myth that somehow the two halves of the pixels, which are under not only one microlens, but also under one color filter block, could somehow magically be used to expand dynamic range "for free" are fooling themselves, and anyone who listens to them. Magic lantern either uses two FULL sensor reads (vs. half sensor reads), or they do line interpolation for half the resolution, to achieve their dynamic range. There is no free increase to dynamic range, and DPAF isn't going to somehow allow more dynamic range for free. The problem with the idea of using one half of the AF photodiodes for an ISO 100 read, and the other half for an ISO 800 read, is that is HALF the light! That is not the same as what ML does, which involves the FULL quantity of light, or else half the light AND half the resolution.

Huh? Please explain how reading both halves at the same gain gets you all the light but reading them at different gains gets you only half the light? How different do the gains have to be to cut the light in half? Is 1% enough?

What you said makes no sense to me.

The photodiodes are SPLIT. Each half gets half the light coming through the lens. It doesn't matter what ISO you read them at...if you read "half"...it's half the light. So your reading half the light at ISO 100, and half the light at ISO 800...well, you really aren't gaining anything. The only way to increase dynamic range by any meaningful amount is to either gather MORE light IN TOTAL...or reduce read noise by a significant degree (i.e. drop it from ~35e- to 3e-). Assuming it ever even becomes possible to read the photodiodes for image purposes like that, you might gain an extremely marginal improvement...but overall, there really isn't any point. It isn't the same as what ML is doing. They are either reading alternate lines of the sensor at two different ISOs, then combining them at HALF THE RESOLUTION, or they are doing two full reads of the sensor. Either way, for the given output size, they double the quantity of light. Reading two HALVES of a SPLIT photodiode gets you...ONE full quantity of light.

You're making no sense.

In all these cases, you're getting the same amount of light because you're starting with the same exposure. The point of reading the halves at different ISOs is to reduce read noise without causing clipping. One side ensures you get the highlights on bright pixels tthe other gives you dramatically reduced read noise on dark pixels. When you combine them, you've effectively increased real bit depth/DR.

Of course, if the halves could both be read out at dramatically lower noise that would be even better, but this is one way to achieve that without having an improved read noise behavior. Canon sensors have dramatically reduced read noise at high ISO, the only issue being saturation.

Nope, nope, and nope. I usually don't get involved in these discussions because I don't need to due to jrista and neuro, but this, nope.

 

[tayassu]

What do you all think are the chances, that the 7D II will surpass the 5D mark iii/1DX on certain things? Such as IQ, ISO, DR or other things?

The 7DII will surpass the 5DIII/1D X in viewfinder magnification, and the 5DIII in frame rate...that's pretty much it.

There also might be several small items with the 7DII like wifi, GPS or a built-in-flash. You can argue about whether you need them, but the 7DII will surpass the other two models on that.

 

[Loswr]

What do you all think are the chances, that the 7D II will surpass the 5D mark iii/1DX on certain things? Such as IQ, ISO, DR or other things?

The 7DII will surpass the 5DIII/1D X in viewfinder magnification, and the 5DIII in frame rate...that's pretty much it.

There also might be several small items with the 7DII like wifi, GPS or a built-in-flash. You can argue about whether you need them, but the 7DII will surpass the other two models on that.

It will be cheaper, too. That's probably the biggest benefit!

 

[Lee Jay]

Further, for everyone else who continues to perpetrate the myth that somehow the two halves of the pixels, which are under not only one microlens, but also under one color filter block, could somehow magically be used to expand dynamic range "for free" are fooling themselves, and anyone who listens to them. Magic lantern either uses two FULL sensor reads (vs. half sensor reads), or they do line interpolation for half the resolution, to achieve their dynamic range. There is no free increase to dynamic range, and DPAF isn't going to somehow allow more dynamic range for free. The problem with the idea of using one half of the AF photodiodes for an ISO 100 read, and the other half for an ISO 800 read, is that is HALF the light! That is not the same as what ML does, which involves the FULL quantity of light, or else half the light AND half the resolution.

Huh? Please explain how reading both halves at the same gain gets you all the light but reading them at different gains gets you only half the light? How different do the gains have to be to cut the light in half? Is 1% enough?

What you said makes no sense to me.

Jrista's right.

Think of it as taking two pictures at the same time. One picture is taken with one side of the pair at high gain, and the other picture is taken with the other side of the pair at low gain. Then the two pictures are combined for greater dynamic range. For the area where the ranges overlap, you are using all the light, but where it does not overlap you only have half of the light...... if you shoot with both halves at the same gain, there is 100% overlap and you use all of the light.

The only way you're going to lose any light is when the high-ISO sampled half is saturated. But that's only when you have too much light in that pixel half, and the other side will still have a lot of light. In other words, this isn't the case where it's a problem.

 

[Marauder]

What do you all think are the chances, that the 7D II will surpass the 5D mark iii/1DX on certain things? Such as IQ, ISO, DR or other things?

The 7DII will surpass the 5DIII/1D X in viewfinder magnification, and the 5DIII in frame rate...that's pretty much it.

There also might be several small items with the 7DII like wifi, GPS or a built-in-flash. You can argue about whether you need them, but the 7DII will surpass the other two models on that.

It will be cheaper, too. That's probably the biggest benefit!

I expect it will also have a touch-screen.

 

[GMCPhotographics]

What do you all think are the chances, that the 7D II will surpass the 5D mark iii/1DX on certain things? Such as IQ, ISO, DR or other things?

The 7DII will surpass the 5DIII/1D X in viewfinder magnification, and the 5DIII in frame rate...that's pretty much it.

There also might be several small items with the 7DII like wifi, GPS or a built-in-flash. You can argue about whether you need them, but the 7DII will surpass the other two models on that.

It will be cheaper, too. That's probably the biggest benefit!

I expect it will also have a touch-screen.

Wowzers....killer new feature..... :-\

 

[Loswr]

What do you all think are the chances, that the 7D II will surpass the 5D mark iii/1DX on certain things? Such as IQ, ISO, DR or other things?

The 7DII will surpass the 5DIII/1D X in viewfinder magnification, and the 5DIII in frame rate...that's pretty much it.

There also might be several small items with the 7DII like wifi, GPS or a built-in-flash. You can argue about whether you need them, but the 7DII will surpass the other two models on that.

It will be cheaper, too. That's probably the biggest benefit!

I expect it will also have a touch-screen.

Wowzers....killer new feature..... :-\

Hey, don't knock it. After all, changing settings with your nose is better than butt-dialing.

 

[wickidwombat]

What do you all think are the chances, that the 7D II will surpass the 5D mark iii/1DX on certain things? Such as IQ, ISO, DR or other things?

The 7DII will surpass the 5DIII/1D X in viewfinder magnification, and the 5DIII in frame rate...that's pretty much it.

There also might be several small items with the 7DII like wifi, GPS or a built-in-flash. You can argue about whether you need them, but the 7DII will surpass the other two models on that.

It will be cheaper, too. That's probably the biggest benefit!

I expect it will also have a touch-screen.

Wowzers....killer new feature..... :-\

Hey, don't knock it. After all, changing settings with your nose is better than butt-dialing.

Hey with a nose the size of mine this is a very real concern :-[

 

[Marauder]

What do you all think are the chances, that the 7D II will surpass the 5D mark iii/1DX on certain things? Such as IQ, ISO, DR or other things?

The 7DII will surpass the 5DIII/1D X in viewfinder magnification, and the 5DIII in frame rate...that's pretty much it.

There also might be several small items with the 7DII like wifi, GPS or a built-in-flash. You can argue about whether you need them, but the 7DII will surpass the other two models on that.

It will be cheaper, too. That's probably the biggest benefit!

I expect it will also have a touch-screen.

Wowzers....killer new feature..... :-\

Hey, don't knock it. After all, changing settings with your nose is better than butt-dialing.

Hey with a nose the size of mine this is a very real concern :-[

Forehead works best! 8)

 

[NancyP]

FWIW, if the photodiode filter arrangement is not the classic Bayer type, but uses some other arrangement (Fuji being the main example), the major software companies, in addition to the DPP in-house software team, will need a bit of time to implement the new filter arrangement into their RAW converters. On the off chance that someone is hoping for a Foveon-ish sensor, the developers will need more than "a bit" of time because the algorithms are a lot different. There's only one non-Sigma RAW developer out there that can use x3f files, Iridient Developer.

 

[Famateur]

This has been another informative thread -- I'm learning a lot. Thanks guys and gals, especially jrista and others on the in-depth tech talk. Very cool stuff.

My guess is that if there's a big improvement in image quality from the sensor, it's probably produced on a new fab. That could also explain the delay in getting the 7DII out the door and perhaps the absence of patents that would point to something totally new.

On the patents things, there is another way they could bring something "totally new" (at least for Canon). They could license or buy a patent from another company. Any thoughts on this? Does Canon take too much pride in their own development to do this? Do they not need to because of the technology they're already working on? Is it still just market dominance that allows them to not need to make a huge leap? (Something tells me that while market dominance might mean they don't need to release a new leap in tech, it doesn't mean they aren't furiously working on developing new tech all the time.)

Anyway, I'm still guessing new fab, but what do you think? Any chance some other company's patent technology shows up in a new killer sensor for the 7DII?

 

[x-vision]

What do you all think are the chances, that the 7D II will surpass the 5D mark iii/1DX on certain things? Such as IQ, ISO, DR or other things?

IMO, the 7DII will at best match the ISO/noise performance of the 5DIII.
And if Canon has finally decided to implement on-chip analog-to-digital conversion (ADC),
DR at low ISO could be better than on the FF cameras.
That's about it, though, in terms of IQ.

Also, just like with the 7D, we might see some features on the 7DII that will later make it
into the higher end cameras.

Overall, it's hard to imagine that the 7DII will offer much more from what you can get
already with the 5DIII today (except for higher frame rate and more pixels per duck).

 

[East Wind Photography]

This has been another informative thread -- I'm learning a lot. Thanks guys and gals, especially jrista and others on the in-depth tech talk. Very cool stuff.

My guess is that if there's a big improvement in image quality from the sensor, it's probably produced on a new fab. That could also explain the delay in getting the 7DII out the door and perhaps the absence of patents that would point to something totally new.

On the patents things, there is another way they could bring something "totally new" (at least for Canon). They could license or buy a patent from another company. Any thoughts on this? Does Canon take too much pride in their own development to do this? Do they not need to because of the technology they're already working on? Is it still just market dominance that allows them to not need to make a huge leap? (Something tells me that while market dominance might mean they don't need to release a new leap in tech, it doesn't mean they aren't furiously working on developing new tech all the time.)

Anyway, I'm still guessing new fab, but what do you think? Any chance some other company's patent technology shows up in a new killer sensor for the 7DII?

Not sure how informative all of the opinions actually are. I would be more interested in the opinion of the guy testing it at the world cup. Short of that, all I want to know is when I can place my pre-order.

 

[Famateur]

Not sure how informative all of the opinions actually are. I would be more interested in the opinion of the guy testing it at the world cup. Short of that, all I want to know is when I can place my pre-order.

Too true regarding predicting what the 7DII will actually have in it.

I just like learning all the info about AA Filters, CFAs, ADCs, read noise, et cetera. Even with conflicting arguments back and forth, the preponderance of info gives me a clearer picture of how works a Bayer-type sensor, even if some of the uber-technical details are up for debate.

 

[LetTheRightLensIn]

Really exciting at this point anything is a bonus! I will be glad to see Canon innovating again!

I'm looking forward to 7d2 technology finding its way to ## and ### series cameras.

I'm personally looking forward to a full-frame (5D) version of the 7D replacement, assuming it's as-rumored.

+1. 7DII...Fall 2014, 5DIV/1DXII Fall of 2015/Spring 2016. That would be 4 years...about right, especially if the technology is truly "revolutionary" I can't see them waiting more than a year (+/-) to get it into their flagship bodies.

No way they hold 5D4 back until 2016!