EOS 7D Mark II & Photokina
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Re: EOS 7D Mark II & Photokina
I'm not really sure what your trying to say. A pizza is a pizza. If it's 15" in diameter, it's ~177" in area. If you slice it up into six slices, each slice is 29.5" in area. If you slice it up into eight slices, each slice is 22" in area. However, if you eat all six larger slices, or eat all eight smaller slices, you still ate 177" total area worth of "pizza." Larger slices don't mean you get more pizza...it's still the same total amount of food regardless of how small you slice it!
sfunglee said:jrista said:Lee Jay said:
HAHA! That's a PERFECT analogy!Sweet. Gotta use that one in the future.
By logically 15" pizza are larger by 6 slices, but the 15" pizza thicker pizza into 8 slices will be different...
In another word, weight per pizza of 1/8 is heavier than 1/6... hrmmm it mean a possible for crop 24mp excel FF 21mp in term of more fine pixel? Sorry i'm no too good into pixel stuffs
I'm not really sure what your trying to say. A pizza is a pizza. If it's 15" in diameter, it's ~177" in area. If you slice it up into six slices, each slice is 29.5" in area. If you slice it up into eight slices, each slice is 22" in area. However, if you eat all six larger slices, or eat all eight smaller slices, you still ate 177" total area worth of "pizza." Larger slices don't mean you get more pizza...it's still the same total amount of food regardless of how small you slice it!
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Re: EOS 7D Mark II & Photokina
Not me.... I just ate a plate of spaghetti so that when the sensor talk got all the way down to string theory, I would be ready....neuroanatomist said:
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Re: EOS 7D Mark II & Photokina
Err... I think you forget to consider the noise factor... if the noise for every pixel is the same, the larger pixel (more signal) will have better Signal-to-Noise ratio... that's mean more pixels equal more noise and since the total signal for the both sensor is the same, the sensor with less pixels will have better Signal-to-Noise ratio. Also, since smaller pixels hold less charge, the chance of blowing highlights is higher than a larger pixel sensor.
As a result, sensors with larger pixel have better dynamic range than sensors with smaller pixel even if the total sensor size is the same.
Have a nice day.
Hi,jrista said:NancyP said:
This is still wrong. Bigger pixels mean more charge per pixel...but it's still the same TOTAL CHARGE for the WHOLE SENSOR!
Same for sensors. You can have two APS-C sensors with 10µm and 5µm pixels. One has four times as many pixels as the other. The sensors are 22.3x14.9mm in size. The big pixel sensor is 2230x1490 pixels, the small pixel sensor is 4460x2980 pixels. One has pixels with four times the area as the other. The 10µm pixels gather 100ke- charge FWC, the 5µm pixels gather 25ke- charge FWC. The bigger pixels are better, right? They gather more light than smaller pixels. They mean less noise, right? Nope. Let's calculate the total charge in the sensor for a fully saturated sensor
(2230*1490) * 100000 = 332,270,000,000e-
(4460*2980) * 25000 = 332,270,000,000e-
Hmm. Something MUST be wrong, because these two sensors gathered the same amount of light! If your subject fills the same absolute area of the sensor, then either sensor is going to gather the same total amount of light. The only difference is that one divides the subject into smaller buckets. Each bucket gets less light, but the subject as a whole is resolved at the sensor with the exact same amount of light in total.
Oh, but I purposely used pixels that had a nice, neat little ratio between them. It doesn't work that way in real life, right? Let's prove the point. Let's take the 5D III and 6D, both full frame sensors. Their total charge capacities are:
5D III: (5760px*3840px) * 67531e-/px = 1,493,677,670,400e-
6D: (5472px*3648px) * 76606e-/px = 1,529,197,940,736e-
The 5D III has 49% Q.E., the 6D has 50% Q.E. Dividing the above by 49% and 50% respectively gives us:
1,493,677,670,400/49 = 30,483,217,763.27
1,529,197,940,736/50 = 30,583,958,814.72
Dividing those numbers gives us:
30,483,217,763.27/30,583,958,814.72 = 0.99670608203273169699921873489352
The 5D III and 6D are within 99.7% of each other as far as total charge goes. That means the difference in light gathering capacity is 0.3%...well within margin of error. Differences in technology, cherry picking the best sensors (as in the 1D X/D4 lines), using better companion electronics (again as in 1D X/D4), etc. can create larger discrepancies, but in general, differences in pixel size, until were talking about very small pixels where fill factor becomes an issue, are largely meaningless. It's sensor area that matters first and foremost, then quantum efficiency...then pixel size/fill factor.
The 7D II could employ some new technology to improve Q.E. They could use better materials (i.e. black silicon), control current better, maybe even switch from using a standard RGGB CFA to using something like color splitting, etc. and maybe double Q.E. That would allow them to realize a REAL one-stop improvement in noise performance at high ISO. I think it's doubtful that's happened...if the 20.2mp sensor rumor is true. In all likelihood, Canon has made some minor evolutionary improvements, maybe improved Q.E. a few percent, maybe found a way to recover some die area for photodiodes, improved the efficiency of their circuitry, etc. I don't expect the differences to be huge.
The 70D has 45% Q.E. The 7D II might have around 49% Q.E., and they may better utilize the sensor die area for photodiodes. We might see a boost from ~26ke- FWC to maybe ~30ke- FWC. That is not going to change things much...and accounting for the differences in quantum efficiency, the two sensors are still going to come within a fraction of a percent of each other as far as total light gathering capacity goes.
Err... I think you forget to consider the noise factor... if the noise for every pixel is the same, the larger pixel (more signal) will have better Signal-to-Noise ratio... that's mean more pixels equal more noise and since the total signal for the both sensor is the same, the sensor with less pixels will have better Signal-to-Noise ratio. Also, since smaller pixels hold less charge, the chance of blowing highlights is higher than a larger pixel sensor.
As a result, sensors with larger pixel have better dynamic range than sensors with smaller pixel even if the total sensor size is the same.
Have a nice day.
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Re: EOS 7D Mark II & Photokina
Nope. I haven't forgotten noise or SNR. The 5µm pixels will have twice the noise. However, a 2x2 matrix of 5µm pixels equal one 10µm pixel in terms of area. Average those four pixels together, and you reduce noise by SQRT(4), which is? Yup. A factor of two. The 10µm pixels have four times the area, which again, reduces noise by SQRT(4), or a factor of two. There is more noise per pixel, however the noise per absolute area of the subject is the same. The sensor with smaller pixels has twice the image dimensions. Downsample the 4460x2980 pixel image to 2230x1490...and there will be no difference in noise.
The only difference you WILL see? The downsampled image is SHARPER! 8)
Have a nice day.
weixing said:
Nope. I haven't forgotten noise or SNR. The 5µm pixels will have twice the noise. However, a 2x2 matrix of 5µm pixels equal one 10µm pixel in terms of area. Average those four pixels together, and you reduce noise by SQRT(4), which is? Yup. A factor of two. The 10µm pixels have four times the area, which again, reduces noise by SQRT(4), or a factor of two. There is more noise per pixel, however the noise per absolute area of the subject is the same. The sensor with smaller pixels has twice the image dimensions. Downsample the 4460x2980 pixel image to 2230x1490...and there will be no difference in noise.
The only difference you WILL see? The downsampled image is SHARPER! 8)
Have a nice day.
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Re: EOS 7D Mark II & Photokina
I realize if it has the 70D sensor that this will disappoint many. But if they keep the price down I'm fine with it. The 70D is a clear improvement in noise/DR over the original 7D, and 65 cross AF points at 10 fps is awesome. I don't think they can coast 5 years on this sensor, but as long as they don't price it into the stratosphere there is nothing that can touch it for action and sports right now outside of the top end 1DX / D4.
Now if they try to charge an arm and a leg for it, I'll just stick to my current 7D for sports/action. If they want to charge more then $2k (street price...we all know MRP is artificially high) then they have to have something "revolutionary" IMHO. Those rumors have been squashed. So we'll see what the price ends up being.
Jaydeep said:
I realize if it has the 70D sensor that this will disappoint many. But if they keep the price down I'm fine with it. The 70D is a clear improvement in noise/DR over the original 7D, and 65 cross AF points at 10 fps is awesome. I don't think they can coast 5 years on this sensor, but as long as they don't price it into the stratosphere there is nothing that can touch it for action and sports right now outside of the top end 1DX / D4.
Now if they try to charge an arm and a leg for it, I'll just stick to my current 7D for sports/action. If they want to charge more then $2k (street price...we all know MRP is artificially high) then they have to have something "revolutionary" IMHO. Those rumors have been squashed. So we'll see what the price ends up being.
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Re: EOS 7D Mark II & Photokina
But for the same focal plane exposure, the smaller pixels also receive less light because, well, they're smaller. So total sensor DR does not necessarily have to suffer for higher resolution sensors.
If all else is held the same, yes. In reality, this doesn't generally always turn out to be true. For one, sometimes manufacturers are able to decrease per-pixel read noise with the smaller pixels of the higher resolution (but same size) sensor. For a sensor of n times higher resolution, all you have to do is decrease per-pixel read noise by a factor of sqrt(n) to achieve equivalent normalized noise performance.
This may be why the Sony A7R has just as much DR as the A7S, and normalized noise performance is similar. But, admittedly, I'm just guessing here.
The point is, there are a number of variables here one must consider. It's not always straightforward. For example, the A7S with its 12MP has demonstrably lower DR in RAW than the A7R with 3x as many pixels. Probably resulting from increased downstream read noise of the architecture.
No, jrista, the noise per absolute area is not the same. It's pretty close, but it's still worse. It'll only be the same if the n-times higher resolution sensor has its pixel-level read noise reduced by a factor of sqrt(n) compared to the lower resolution sensor. Let's take the case of a 10µm x 10µm pixel, vs. this pixel divided up into four 5µm x 5µm pixels. Let's do some math:
For a 10µm pixel that receives 200 photons, QE=50%:
For the four 5µm pixels that also receive a total of 200 photons, or 50 photons each, QE=50%:
Point is, SNR of 9.8 > SNR of 9.3. This is generally a bit academic of a difference, which is why high resolution sensors generally do so well. But for extremely high ISOs, where you have so little signal to begin with, it can make a difference. Or when the higher resolution sensor has many, many more pixels.
The take-home point is that when you average the smaller pixels of a n-times higher resolution sensor, you completely equalize shot-noise performance per-area. But not read noise performance. Why? Simply b/c you have n times as many read events.
weixing said:
But for the same focal plane exposure, the smaller pixels also receive less light because, well, they're smaller. So total sensor DR does not necessarily have to suffer for higher resolution sensors.
weixing said:
If all else is held the same, yes. In reality, this doesn't generally always turn out to be true. For one, sometimes manufacturers are able to decrease per-pixel read noise with the smaller pixels of the higher resolution (but same size) sensor. For a sensor of n times higher resolution, all you have to do is decrease per-pixel read noise by a factor of sqrt(n) to achieve equivalent normalized noise performance.
This may be why the Sony A7R has just as much DR as the A7S, and normalized noise performance is similar. But, admittedly, I'm just guessing here.
The point is, there are a number of variables here one must consider. It's not always straightforward. For example, the A7S with its 12MP has demonstrably lower DR in RAW than the A7R with 3x as many pixels. Probably resulting from increased downstream read noise of the architecture.
jrista said:
No, jrista, the noise per absolute area is not the same. It's pretty close, but it's still worse. It'll only be the same if the n-times higher resolution sensor has its pixel-level read noise reduced by a factor of sqrt(n) compared to the lower resolution sensor. Let's take the case of a 10µm x 10µm pixel, vs. this pixel divided up into four 5µm x 5µm pixels. Let's do some math:
For a 10µm pixel that receives 200 photons, QE=50%:
- Signal = 100 (50% of 200 = 100 electrons)
- Read noise=2
- Shot noise = sqrt(100) = 10
- Total noise = sqrt (10^2 + 2^2) = 10.198 [yes, this is an approximation, but it'll suffice]
- Per-pixel SNR = 100/10.198 = 9.806
For the four 5µm pixels that also receive a total of 200 photons, or 50 photons each, QE=50%:
- Signal = 25 (50% of 50 = 25 electrons)
- Read noise = 2
- Shot noise = sqrt(25) = 5
- Total noise = sqrt (5^2 + 2^2) = 5.385
- Per-pixel SNR = 25/5.385 = 4.6424
- After averaging those 4 pixels, SNR increases by sqrt(4)=2, so SNR for that area is now 9.285
- Another way of determining the SNR of the four averaged pixels is to calculate out the noise: total noise after averaging will be sqrt(4*sqrt(29)^2) = sqrt(116) which you can already tell is going to be more than sqrt(104), the total noise of the 10µm pixel. But let's continue: sqrt(116) = 10.77. Adding together the signal of the 4 pixels gives you a signal of 100. So SNR = 100/10.77 = 9.285.
Point is, SNR of 9.8 > SNR of 9.3. This is generally a bit academic of a difference, which is why high resolution sensors generally do so well. But for extremely high ISOs, where you have so little signal to begin with, it can make a difference. Or when the higher resolution sensor has many, many more pixels.
The take-home point is that when you average the smaller pixels of a n-times higher resolution sensor, you completely equalize shot-noise performance per-area. But not read noise performance. Why? Simply b/c you have n times as many read events.
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Re: EOS 7D Mark II & Photokina
How? If it is 12MP then it's getting to be not the ton more reach than a 5D3 is. It's not the crop factor that matters, it's the photosite density. All teh crop factor does is limit your FOV with each lens.
Canon1 said:
How? If it is 12MP then it's getting to be not the ton more reach than a 5D3 is. It's not the crop factor that matters, it's the photosite density. All teh crop factor does is limit your FOV with each lens.
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Re: EOS 7D Mark II & Photokina
If they really did manage to pull of one the rumors where they claim it does DPAF so quickly that it after phase AF it can do quick final DPAF check and adjustment so fast that it wouldn't hurt reaction time (which seems hard to believe), but if they could, man it would have the best AF bar none and it would be an AF revolution.
raptor3x said:
If they really did manage to pull of one the rumors where they claim it does DPAF so quickly that it after phase AF it can do quick final DPAF check and adjustment so fast that it wouldn't hurt reaction time (which seems hard to believe), but if they could, man it would have the best AF bar none and it would be an AF revolution.
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Re: EOS 7D Mark II & Photokina
That is really asking a lot, to do that it would basically have to be very nearly the 100% ideal sensor to simply match the 5D3 for SNR. It's a totally unrealistic ask. If you mean for DR then sure, it could do 3 stops better low ISO and 1.5 high ISO than the 5D3 for sure, but for SNR you are just not asking something it is remotely realistic.
You have to understand how crazy good the SNR of the current top cams are at high iso already. There isn't all that much room left to improve without breaking very basic laws of physics.
Maui5150 said:
That is really asking a lot, to do that it would basically have to be very nearly the 100% ideal sensor to simply match the 5D3 for SNR. It's a totally unrealistic ask. If you mean for DR then sure, it could do 3 stops better low ISO and 1.5 high ISO than the 5D3 for sure, but for SNR you are just not asking something it is remotely realistic.
You have to understand how crazy good the SNR of the current top cams are at high iso already. There isn't all that much room left to improve without breaking very basic laws of physics.
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Re: EOS 7D Mark II & Photokina
It does if you were told "don't eat more than two slices!!!!" ;D.
Lee Jay said:
It does if you were told "don't eat more than two slices!!!!" ;D.
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Re: EOS 7D Mark II & Photokina
Really, so these new APS-C cams are doing like like say capturing more photons than exist in a scene???
Keith_Reeder said:
Really, so these new APS-C cams are doing like like say capturing more photons than exist in a scene???
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Re: EOS 7D Mark II & Photokina
At extremes of pixel size it can matter a bit for SNR. For lots of tech if you go wayyyyyyy high and compare to vastly lower you can get a bit of an actual penalty with the tech Canon is using now, but for anything like say 12MP vs 24MP I mean it's not even worth thinking about (and the more MP can even maybe help the DR a trace, plus the more MP the tighter the 'grain' which pleases the eye more which would make up for more than any little difference). So you might get a bit better DR and a bit worse SNR for typical modern tech and the way it works out, but for it to matter to the point you'd really care, especially for SNR you need quite a difference.
Keith_Reeder said:
At extremes of pixel size it can matter a bit for SNR. For lots of tech if you go wayyyyyyy high and compare to vastly lower you can get a bit of an actual penalty with the tech Canon is using now, but for anything like say 12MP vs 24MP I mean it's not even worth thinking about (and the more MP can even maybe help the DR a trace, plus the more MP the tighter the 'grain' which pleases the eye more which would make up for more than any little difference). So you might get a bit better DR and a bit worse SNR for typical modern tech and the way it works out, but for it to matter to the point you'd really care, especially for SNR you need quite a difference.
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Re: EOS 7D Mark II & Photokina
so?
lots of those of those quotes are simply about not imagining better tech, which is far different than going up against limits of basic physics and some are ridiculously flat out misinterpretations of basic physics that were well known by anyone who actually knew physics then
roguewave said:neuroanatomist said:
I don't disagree with you about sensors, but still, be careful betting all your money on it...
"Heavier than air flying machines are impossible."
-- Lord Kelvin, president, Royal Society, 1895
"The resistance of air increases as the square of the speed and works as the cube [of speed].... It is clear that with our present devices there is no hope of aircraft competing for racing speed with either our locomotives or automobiles."
-- William H. Pickering, Director, Harvard College Observatory, 1910
"Even considering the improvements possible...the gas turbine could hardly be considered a feasible application to airplanes because of the difficulties of complying with the stringent weight requirements."
-- U. S. National Academy Of Science, 1940
"Professor Goddard...does not know the relation of action to re-action, and the need to have something better than a vacuum against which to react....he only seems to lack the knowledge ladled out daily in high schools."
-- 1920 New York Times editorial on Robert Goddard's rocket work.
"The energy produced by the breaking down of the atom is a very poor kind of thing. Anyone who expects a source of power from the transformations of these atoms is talking moonshine."
-- Ernest Rutherford, 1930
"This foolish idea of shooting at the moon is an example of the absurd length to which vicious specialization will carry scientists. To escape the Earth's gravitation a projectile needs a velocity of 7 miles per second. The thermal energy at this speed is 15,180 calories [per gram]. Hence the proposition appears to be basically impossible"
-- A. W. Bickerton, 1926
"Fooling around with alternating currents is just a waste of time. Nobody will use it, ever."
-- Thomas Edison
so?
lots of those of those quotes are simply about not imagining better tech, which is far different than going up against limits of basic physics and some are ridiculously flat out misinterpretations of basic physics that were well known by anyone who actually knew physics then
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Re: EOS 7D Mark II & Photokina
I think the 6D is already something like at leat 2 stops better DR at high ISO than the 7D and Exmor is like 3 stops so certainly at least 3 stops low ISO and 2 stops high ISO without even having to do anything revolutionary.
digitalride said:
I think the 6D is already something like at leat 2 stops better DR at high ISO than the 7D and Exmor is like 3 stops so certainly at least 3 stops low ISO and 2 stops high ISO without even having to do anything revolutionary.
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Re: EOS 7D Mark II & Photokina
you really should compare using the normalized chart:
http://www.dxomark.com/Cameras/Compare/Side-by-side/Canon-EOS-70D-versus-Canon-EOS-5D___895_176
that said it still doesn't quite match the 5D, much less outdo it
neuroanatomist said:Keith_Reeder said:
Keith_Reeder said:
Yes, even DxO gets how far we've come, that a new APS-C sensor like that in the 70D is waaay better in terms of high ISO noise than an old FF sensor like that in the original 5D.
:
you really should compare using the normalized chart:
http://www.dxomark.com/Cameras/Compare/Side-by-side/Canon-EOS-70D-versus-Canon-EOS-5D___895_176
that said it still doesn't quite match the 5D, much less outdo it
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Re: EOS 7D Mark II & Photokina
Add me to the list of people hoping it's a 24MP - not because I want that number (though it would be a nice bump!) but because of 20.2 indicating it's a derivative of the 70D sensor. I really like using my 70D but it's the big jump in sensor tech I want Canon to do and even if you aren't directly interested in the 7D II at least it shows what they have done will feature in future bodies.
Add me to the list of people hoping it's a 24MP - not because I want that number (though it would be a nice bump!) but because of 20.2 indicating it's a derivative of the 70D sensor. I really like using my 70D but it's the big jump in sensor tech I want Canon to do and even if you aren't directly interested in the 7D II at least it shows what they have done will feature in future bodies.
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Re: EOS 7D Mark II & Photokina
The problem with the basic laws of physics is that our understanding of them has always been incomplete. They still are.
The problem with the basic laws of physics is that our understanding of them has always been incomplete. They still are.
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