August 21, 2014, 05:01:39 AM

Author Topic: 1d IV vs. 7D II  (Read 16343 times)

jrista

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Re: 1d IV vs. 7D II
« Reply #105 on: April 22, 2014, 01:23:54 PM »
On the basis of better IQ and lesser noise at high ISO, there's a good chance the 7D II will be at least as good as the 1D IV. In there last few years, there have been great strides made in sensor technology. Let's hope the camera that finally comes to market doesn't have too many, hence smaller, pixels to negate that virtue.
On the other hand, the reliability and durability of the 7d II will likely not come close to the 1D IV (nor any others in the 1D family) unless it's sold at a price point above the 5D III. Since it's being billed as a prosumer camera, we can  be pretty certain THAT's not going to happen.


There have been strides in sensor technology, however pixel size still dominates the determination of how much noise you have. Smaller pixels will always have more noise, that's a simple matter of physics. We have improved READ noise with better sensor technology, but read noise is only a small contribution to total noise (especially at high ISO)...photon shot noise is the primary source of noise in images. The larger pixels of the 1D IV will always win out against smaller pixels of APS-C sensors. The only way the 7D II could do better is if it had larger pixels than the 1D IV, however that would make it something like a 10mp sensor...highly unlikely.


This statement is not true, a smaller pixel generates less noise but also have a lower FWC due the psycial size.
http://theory.uchicago.edu/~ejm/pix/20d/tests/noise/noise-p3.html


A smaller pixel generates less read noise, correct. For example, the 7D has 8e- read noise, vs. the 1D X's 35e- read noise. But read noise is a tiny, tiny, tiny contributor to overall noise. The lower FWC means TOTAL noise (including photon shot noise) is higher, because your maximum signal (as dictated by that lower FWC) is lower.

The overall sensor area is what dictates total noise in the image, and in that respect it doesn't really matter what the pixel size is. Smaller sensors have more noise than larger sensors due to their smaller total area/less total light gathered.
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Re: 1d IV vs. 7D II
« Reply #105 on: April 22, 2014, 01:23:54 PM »

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Re: 1d IV vs. 7D II
« Reply #106 on: April 22, 2014, 04:53:13 PM »

You dont get it, do you?


Oh yes, I get it, but you obviously didn't. I am calling you out and asking for actual images of yours that support your theory. And now note you arlimiting the comparison to focal length limited situations, which isn't particularly valid most of the time for most people.

Read my posts again and look forposts where I did not clearly said the example is  for reach limited situations.

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Re: 1d IV vs. 7D II
« Reply #107 on: April 22, 2014, 05:00:24 PM »

You dont get it, do you?



Oh yes, I get it, but you obviously didn't. I am calling you out and asking for actual images of yours that support your theory. And now note you arlimiting the comparison to focal length limited situations, which isn't particularly valid most of the time for most people.


Read my posts again and look forposts where I did not clearly said the example is  for reach limited situations.


Read my posts again and show me an example of what you believe you are seeing, that the 7D outperforms the 1D MkIV in focal length limited situations, because the crops of yours I have seen support completely the opposite.

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Re: 1d IV vs. 7D II
« Reply #108 on: April 22, 2014, 05:27:08 PM »
Sounds like you are shooting jpg only.  ;)
To compensate for the higher amont of pixels on the subject you need to put a extra tc on the lens on 1d4.
This will cancel out the one stop iso advantage 1d4 has vs 7d.
Also the af will be slower due 1 stop slower lens (with tc).
If You are in a reach limited situation with the 500mm + tc's and the two bodys, what combination would you use?
1d4 + 2x tc or 7d+1.4tc?

Assuming the shot is worth taking, 1D4 + 2x.  No question.  The result will be much better.  Even at a higher ISO the 1D4 will give a more manageable picture.  Literally every professional bird/nature photographer would agree.  The disadvantages of the smaller sensor outweigh the small advantage of crop reach.  Note how everyone who can afford it has moved up to the full frame 1DX and the 5DmkIII has become a viable wildlife camera.  Crop reach is largely illusory and only a legitimate factor in a tiny fraction of shooting situations.  Most of the time if the crop would make the difference, you are too far away to take a decent pic anyway.

So you are serious claiming that a 1d4 + 500mmf4 is mk1 +2x tc will outperform 7d+ same lens + 1.4x tc?
Have you ever tested the 500mm with a 2x tc?
And are you serious claiming the af will be better too?
You must be joking!

The 7d combo will win regarding details and AF speed. Noise will be equal.
Maybe you would stick with 1d4 +1.4 tc. In this case the 1d4 af will be better.  7d will have better details but more noise. However, you can easily pp the more detailed image from 7d and then downsample to show same subject size at 1d4. Again, the 7d will win. At least for isos up to somewhere betwen 1600 and 3200.

This is simply untrue in any real world application.  I've used both cameras extensively and the 7D was a major source of frustration comparatively, particularly and most noticeably when dealing with noise in post. 

The thing is, your own portfolio (which is very nice btw!) demonstrates this difference.  The shots you've taken with the 1d4 are much cleaner and more detailed compared with the shots you've taken with the 7D which generally show quite a bit more noise, even in those downsampled images.  I could clearly pick them out before looking at the technical details at the bottom.  The only ones that I guessed wrong were the black backed gull (which I thought was 1D4) and the Guillemot (which I thought was 7D).  For the rest it was easy to see the difference in quality.

If you really can see what camera was used for all these images without looking at the exif, I must say Im impressed!
But remember, all the 7d images was taken in reach limited situations, while the 1d4 was not.
I have both cameras and takes the one that suits the situation best. If cropping is necessary and the light is good, the 7d easily wins. And im quite sure it will win against 5d3 too, in those situations.

You said spot af is the only thing you miss from 7d. What about a quick way of change shooting setup from BIF mode to static mode? If you are a birder and dont miss that, I doubt you seriously have used these bodys. Or maybe you can give me a good tip ;)

I always have my 1D4 in servo mode and I switch between 45pt and center point with the joystick.  With the 7D I had to switch between servo and one shot constantly because the 7D would bounce when using servo on a stationary subject.  This isn't an issue with the 1 series AF.  My two big complaints with the 7D, an otherwise great camera, are with noise and the almost-excellent-but-fatally-flawed AF system.

I think there is a reason why they changed menus more to 7d style than 1d4 style both in 5d3 and 1dx.
Using your method, I have to click 3 different buttons in a total of 5 clicks to change mode. (Both af points and select predefined bif shutter/ev comp setting) On 7d I only need one click.

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Re: 1d IV vs. 7D II
« Reply #109 on: April 22, 2014, 06:11:34 PM »
So you are serious claiming that a 1d4 + 500mmf4 is mk1 +2x tc will outperform 7d+ same lens + 1.4x tc?

Yes, that's what I'm saying.  I thought it was pretty clear.

I have used the 500 with a 2x TC.  It works pretty well.  Also, you get more reach with the 500 + 2x on the 1d4 than you get with the 500 + 1.4x on the 7D by about 180mm equiv. meaning you will have to crop less, meaning less noise and better IQ.  I didn't make any statements about the AF in that comparison.

Quote
I think there is a reason why they changed menus more to 7d style than 1d4 style both in 5d3 and 1dx.
Using your method, I have to click 3 different buttons in a total of 5 clicks to change mode. (Both af points and select predefined bif shutter/ev comp setting) On 7d I only need one click.

My method requires pushing the AF select button and then clicking the stick to toggle 45pt or center point.  Its just about the easiest and fastest thing in the world.  Maybe I'm misunderstanding what you mean by predefined BIF settings.  I don't use custom profiles (I shoot manual  8)), is that what you are talking about?

Anyway, no point in continuing to argue about this.  If you like the 7D better, that's awesome, have at it.  You take some nice pics, keep it up in what ever way works best for you.

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Re: 1d IV vs. 7D II
« Reply #110 on: April 23, 2014, 03:29:17 AM »
I thought this topic was going to be ideal because I have a chance of getting a mint 1dmk 1v with no more than 7500 clicks. I will trade my 7d against this camera. I am no longer prepared to wait for the fabled 7dmk11.
Given the number of pages posted here on the merits of full frame v crop ( I already have the 5dmk111 and love it) could anybody confirm whether the 1dmk iv will be better than the 7d in terms of overall image quality.

I know build quality will be improved and noise as well as autofocus will be better. I will be using this body with either the 300f2.8mk11 or 70-200f2.8mk11 + extenders.

Guys and girls a simple reply would be appreciated without going into the theorem of Pythagoras. I get lost with some of the technical stuff you all come up with.
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Re: 1d IV vs. 7D II
« Reply #111 on: April 23, 2014, 04:55:35 AM »
could anybody confirm whether the 1dmk iv will be better than the 7d in terms of overall image quality.

Guys and girls a simple reply would be appreciated without going into the theorem of Pythagoras. I get lost with some of the technical stuff you all come up with.

Simple answer is, yes.
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Re: 1d IV vs. 7D II
« Reply #111 on: April 23, 2014, 04:55:35 AM »

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Re: 1d IV vs. 7D II
« Reply #112 on: April 23, 2014, 05:17:46 AM »


There have been strides in sensor technology, however pixel size still dominates the determination of how much noise you have. Smaller pixels will always have more noise, that's a simple matter of physics. We have improved READ noise with better sensor technology, but read noise is only a small contribution to total noise (especially at high ISO)...photon shot noise is the primary source of noise in images. The larger pixels of the 1D IV will always win out against smaller pixels of APS-C sensors. The only way the 7D II could do better is if it had larger pixels than the 1D IV, however that would make it something like a 10mp sensor...highly unlikely.

A smaller pixel generates less read noise, correct. For example, the 7D has 8e- read noise, vs. the 1D X's 35e- read noise. But read noise is a tiny, tiny, tiny contributor to overall noise. The lower FWC means TOTAL noise (including photon shot noise) is higher, because your maximum signal (as dictated by that lower FWC) is lower.

The overall sensor area is what dictates total noise in the image, and in that respect it doesn't really matter what the pixel size is. Smaller sensors have more noise than larger sensors due to their smaller total area/less total light gathered.

Jrista, I'm a little confused by your two statements - which seem at odds with each other, unless I misunderstand them. 

My understanding is noise is determined by the total light gathered by the system, and that is a function of the sensor's area and its quantum efficiency.  That would mean changing the 7D sensor for one which is the same size but has a smaller number of much larger pixels (which otherwise performed the same) wouldn't help with noise, because you wouldn't change the total light gathered by the system.  Larger pixels would presumably have a larger FWC, which might enable more subtle colour/brightness gradation (and perhaps increase dynamic range?), but wouldn't actually reduce noise.

Am I missing something?
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Re: 1d IV vs. 7D II
« Reply #113 on: April 23, 2014, 06:24:02 AM »
I thought this topic was going to be ideal because I have a chance of getting a mint 1dmk 1v with no more than 7500 clicks. I will trade my 7d against this camera. I am no longer prepared to wait for the fabled 7dmk11.
Given the number of pages posted here on the merits of full frame v crop ( I already have the 5dmk111 and love it) could anybody confirm whether the 1dmk iv will be better than the 7d in terms of overall image quality.

I know build quality will be improved and noise as well as autofocus will be better. I will be using this body with either the 300f2.8mk11 or 70-200f2.8mk11 + extenders.

Guys and girls a simple reply would be appreciated without going into the theorem of Pythagoras. I get lost with some of the technical stuff you all come up with.

I think the answers will be exaxt the same if you compare (IQ) between your 7D vs 5D3:

My experience:
When no cropping is needed: 1D4 gives best IQ
If you need to crop  1D4 more than 7D FOV (using the same lens) and use lower iso than iso 2000: 7D gives (slightly) better IQ.



jrista

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Re: 1d IV vs. 7D II
« Reply #114 on: April 23, 2014, 10:33:15 AM »


There have been strides in sensor technology, however pixel size still dominates the determination of how much noise you have. Smaller pixels will always have more noise, that's a simple matter of physics. We have improved READ noise with better sensor technology, but read noise is only a small contribution to total noise (especially at high ISO)...photon shot noise is the primary source of noise in images. The larger pixels of the 1D IV will always win out against smaller pixels of APS-C sensors. The only way the 7D II could do better is if it had larger pixels than the 1D IV, however that would make it something like a 10mp sensor...highly unlikely.

A smaller pixel generates less read noise, correct. For example, the 7D has 8e- read noise, vs. the 1D X's 35e- read noise. But read noise is a tiny, tiny, tiny contributor to overall noise. The lower FWC means TOTAL noise (including photon shot noise) is higher, because your maximum signal (as dictated by that lower FWC) is lower.

The overall sensor area is what dictates total noise in the image, and in that respect it doesn't really matter what the pixel size is. Smaller sensors have more noise than larger sensors due to their smaller total area/less total light gathered.

Jrista, I'm a little confused by your two statements - which seem at odds with each other, unless I misunderstand them. 

My understanding is noise is determined by the total light gathered by the system, and that is a function of the sensor's area and its quantum efficiency.  That would mean changing the 7D sensor for one which is the same size but has a smaller number of much larger pixels (which otherwise performed the same) wouldn't help with noise, because you wouldn't change the total light gathered by the system.  Larger pixels would presumably have a larger FWC, which might enable more subtle colour/brightness gradation (and perhaps increase dynamic range?), but wouldn't actually reduce noise.

Am I missing something?

That is essentially correct. Pixel size doesn't matter much because you can always downsample, which is effectively the same as either binning or having larger pixels. Let's say you have a 32mp APS-C and a 8mp APS-C. Both sensors have a Q.E. of 50%. Neither sensor has an AA filter. These two sensors are a factor of four difference in pixel size...you can fit four of the 32mp sized pixels into one 8mp sized pixel. If you take the 32mp image and downsample it to 8mp (8000x4000 pixels downsampled to 4000x2000 pixels), the results are the same. The per-pixel noise of the 32mp image is higher, however once downsampled, basic averaging effectively nullifies the increase in noise, and largely nullifies the increase in detail, resulting in nearly the same detail and exactly the same noise as the 8mp sensor. The detail will be slightly higher as you started out with a finer level of detail, and the multi-sampling process of downsampling means that while you are concurrently averaging out noise, you are also compounding the quality of detail in each pixel.

Now, let's say the 8mp camera has 40% Q.E. and the 32mp camera has 80% Q.E. Now the 32mp camera only has noise that is 50% worse than the 8mp, rather than twice as bad. If you downsample the 32mp image to the same dimensions as the 8mp image, the downsampled 32mp image will have less noise and will show the same advantage in detail. It is highly unlikely we will ever see a consumer-grade sensor with 80% Q.E. I've only seen those levels in Grade 1 scientific sensors (the kinds of sensors you find in astrophotography cameras or the stuff they ship up to the Hubble.) We may see sensors with 65% Q.E. or so, however that is only about a half-stop improvement over the ~50% most current sensors have now.

Now, let's say we have two sensors of differing size. Let's say we have a 16mp mp FF sensor, and an 8mp 24x16mm sensor (exactly half the area of the FF sensor, slightly larger than APS-C). Both cameras have exactly the same pixel size. If you frame your subject in one vertical half of the FF sensor with the camera oriented vertically, and crop out the other half, you will have identical results to the 8mp APS-C sensor. If you frame the same subject horizontally using the full area of the FF sensor, you are putting twice as much sensor area on the subject. You have gathered double the amount of light with the FF sensor as you are with the APS-C sensor...and it has nothing to do with pixel size. If you downsample the FF image to the same dimensions as the APS-C image, your going to trounce it in both noise levels and detail levels.

The total amount of light gathered is really what matters. Assuming the same sensor size, then the actual pixel size does not really matter all that much. There are things that may result in improved performance of one sensor with one pixels size or another. Improved quantum efficiency is one way. There are also caveats with pixel size. If you want more pixels, that also means more wiring. In FSI sensors, the increased wiring with smaller pixels means there is even less total light sensitive area than with larger pixels. Theoretically, assuming an identical fabrication process is used, our 8mp camera from above will actually have more total photodiode (light sensitive) area than the 32mp sensor. If they both have the same Q.E. then the 8mp sensor will actually perform slightly better due to the slightly greater total photodiode area. This would be the only way I think a 7D II could perform as well as or better (highly unlikely) than the 1D IV. By reducing pixel count significantly, one can increase the total amount of light-sensitive sensor area. I'm not exactly sure where the cutoff point would be...however you would have to pretty drastically reduce the wiring area of the 7D II. You would probably also need to use a process shrink (500nm to 180nm). Another way to do it would be to move to a BSI design. (This all assumes that there is enough wiring in the 1D IV sensor that total light sensitive area is still not greater than the area of an APS-C sensor...if it is, then actually there wouldn't be any way the 7D II could actually perform better.)

In this respect, you are indeed correct about color fidelity and dynamic range...larger pixels do have an edge here. However you are still going to find that greater total sensor area still has a greater impact on those aspects of IQ than larger pixels do in the long run (for example, the D800 has phenomenal color fidelity, however it's pixel size is only marginally larger than the 7D, which has pretty terrible color fidelity in the grand scheme of things...the greater total light gathering capacity, benefited by both higher Q.E. and being FF, of the D800 is it's real edge here.)

Other technology may be employed to increase the total light sensitivity of a sensor pixel. Currently sensors are effectively two dimensional...the only thing that really matters for total charge capacity is the area of the photodiode. Foveon-type sensors stack photodiodes, resulting in an increase in total charge capacity for each pixel. The same technique could theoretically be employed for monochrome and bayer sensors. Blue pixels would be least sensitive, as silicon will filter out most of the bluer wavelengths before they penetrate deeply. Green and red pixels would be most sensitive, allowing for two or three, maybe even four layers of photodiodes. Such technology could be employed in higher megapixel sensors to increase FWC and sensitivity. There is nothing that says the same techniques couldn't be employed with larger pixel sensors, though.
« Last Edit: April 23, 2014, 10:39:35 AM by jrista »
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jrista

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Re: 1d IV vs. 7D II
« Reply #115 on: April 23, 2014, 10:46:43 AM »
I thought this topic was going to be ideal because I have a chance of getting a mint 1dmk 1v with no more than 7500 clicks. I will trade my 7d against this camera. I am no longer prepared to wait for the fabled 7dmk11.
Given the number of pages posted here on the merits of full frame v crop ( I already have the 5dmk111 and love it) could anybody confirm whether the 1dmk iv will be better than the 7d in terms of overall image quality.

I know build quality will be improved and noise as well as autofocus will be better. I will be using this body with either the 300f2.8mk11 or 70-200f2.8mk11 + extenders.

Guys and girls a simple reply would be appreciated without going into the theorem of Pythagoras. I get lost with some of the technical stuff you all come up with.

So long as you compose your shots the same with the 1D IV as you would with the 7D II (i.e. the subject is framed the same), then yes, the 1D IV should perform better in pretty much every case. The only time a smaller sensor is better is when you are reach-limited, in which case your subject would be reproduced at the sensor the same size with both cameras. You'll get the same amount of light on the subject, as far as sensor area goes, however with the smaller pixels that are usually used with APS-C sensors, you'll generally get more detail.

If the 7D II hits the street with a strong AA filter, or a less than ideal full well capacity, then it is unlikely it would even perform as well as the 1D IV in reach-limited scenarios. (The 7D has a 20187e- FWC, where as the 70D has a 26726e- FWC DESPITE having smaller pixels...so it is likely that the 7D II will also have a better FWC.) I think it is most likely that the 7D II will hit with a slightly weak AA filter, as that's been the trend, I think it will also have improved Q.E., so I think it will have an FWC between 26ke- and 28ke-. For what it is, it should perform quite well...but regardless of how well, if your filling your frame with the subject, the 1D IV is still going to outperform it.
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Re: 1d IV vs. 7D II
« Reply #116 on: April 23, 2014, 02:55:01 PM »
If the 7D II hits the street with a strong AA filter, or a less than ideal full well capacity, then it is unlikely it would even perform as well as the 1D IV in reach-limited scenarios. (The 7D has a 20187e- FWC, where as the 70D has a 26726e- FWC DESPITE having smaller pixels...so it is likely that the 7D II will also have a better FWC.) I think it is most likely that the 7D II will hit with a slightly weak AA filter, as that's been the trend, I think it will also have improved Q.E., so I think it will have an FWC between 26ke- and 28ke-. For what it is, it should perform quite well...but regardless of how well, if your filling your frame with the subject, the 1D IV is still going to outperform it.

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Re: 1d IV vs. 7D II
« Reply #117 on: April 23, 2014, 03:50:35 PM »
So long as you compose your shots the same with the 1D IV as you would with the 7D II (i.e. the subject is framed the same), then yes, the 1D IV should perform better in pretty much every case.

Not to stir things up and certainly not to question Jon in any way, but...

I think in fairness it should be noted that we are talking about the margins here. Yes, the 1D IV should perform better in pretty much every case, but whether that "better" performance is visible or of any practical value is another question.

I now own both a 5DIII and a 7D and I want to rationalize the 5D purchase as much as anyone. Yet, if I am honest about it, there are very few circumstances where the differences are even noticeable. Yeah, it saved my rear when I had to shoot existing light in a dimly lit theater and had no choice but to use obscenely high ISOs. I am also not talking about the other feature differences or the depth of field differences between full frame and crop. 

But, strictly in terms of the quality of images coming out of both cameras; for anyone shooting at ISO 400 or so and printing rather than pixel-peeping, the differences are insignificant even at large print sizes.

On these pages, Jon and others have provided a very good reality check about the upper limits of sensor performance. I think it's also good to provide a reality check about the very narrow parameters we are talking about when it comes to visible differences in sensor performance.
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Re: 1d IV vs. 7D II
« Reply #117 on: April 23, 2014, 03:50:35 PM »

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Re: 1d IV vs. 7D II
« Reply #118 on: April 23, 2014, 10:00:03 PM »


There have been strides in sensor technology, however pixel size still dominates the determination of how much noise you have. Smaller pixels will always have more noise, that's a simple matter of physics. We have improved READ noise with better sensor technology, but read noise is only a small contribution to total noise (especially at high ISO)...photon shot noise is the primary source of noise in images. The larger pixels of the 1D IV will always win out against smaller pixels of APS-C sensors. The only way the 7D II could do better is if it had larger pixels than the 1D IV, however that would make it something like a 10mp sensor...highly unlikely.

A smaller pixel generates less read noise, correct. For example, the 7D has 8e- read noise, vs. the 1D X's 35e- read noise. But read noise is a tiny, tiny, tiny contributor to overall noise. The lower FWC means TOTAL noise (including photon shot noise) is higher, because your maximum signal (as dictated by that lower FWC) is lower.

The overall sensor area is what dictates total noise in the image, and in that respect it doesn't really matter what the pixel size is. Smaller sensors have more noise than larger sensors due to their smaller total area/less total light gathered.

Jrista, I'm a little confused by your two statements - which seem at odds with each other, unless I misunderstand them. 

My understanding is noise is determined by the total light gathered by the system, and that is a function of the sensor's area and its quantum efficiency.  That would mean changing the 7D sensor for one which is the same size but has a smaller number of much larger pixels (which otherwise performed the same) wouldn't help with noise, because you wouldn't change the total light gathered by the system.  Larger pixels would presumably have a larger FWC, which might enable more subtle colour/brightness gradation (and perhaps increase dynamic range?), but wouldn't actually reduce noise.

Am I missing something?

That is essentially correct. Pixel size doesn't matter much because you can always downsample, which is effectively the same as either binning or having larger pixels. Let's say you have a 32mp APS-C and a 8mp APS-C. Both sensors have a Q.E. of 50%. Neither sensor has an AA filter. These two sensors are a factor of four difference in pixel size...you can fit four of the 32mp sized pixels into one 8mp sized pixel. If you take the 32mp image and downsample it to 8mp (8000x4000 pixels downsampled to 4000x2000 pixels), the results are the same. The per-pixel noise of the 32mp image is higher, however once downsampled, basic averaging effectively nullifies the increase in noise, and largely nullifies the increase in detail, resulting in nearly the same detail and exactly the same noise as the 8mp sensor. The detail will be slightly higher as you started out with a finer level of detail, and the multi-sampling process of downsampling means that while you are concurrently averaging out noise, you are also compounding the quality of detail in each pixel.

Now, let's say the 8mp camera has 40% Q.E. and the 32mp camera has 80% Q.E. Now the 32mp camera only has noise that is 50% worse than the 8mp, rather than twice as bad. If you downsample the 32mp image to the same dimensions as the 8mp image, the downsampled 32mp image will have less noise and will show the same advantage in detail. It is highly unlikely we will ever see a consumer-grade sensor with 80% Q.E. I've only seen those levels in Grade 1 scientific sensors (the kinds of sensors you find in astrophotography cameras or the stuff they ship up to the Hubble.) We may see sensors with 65% Q.E. or so, however that is only about a half-stop improvement over the ~50% most current sensors have now.

Now, let's say we have two sensors of differing size. Let's say we have a 16mp mp FF sensor, and an 8mp 24x16mm sensor (exactly half the area of the FF sensor, slightly larger than APS-C). Both cameras have exactly the same pixel size. If you frame your subject in one vertical half of the FF sensor with the camera oriented vertically, and crop out the other half, you will have identical results to the 8mp APS-C sensor. If you frame the same subject horizontally using the full area of the FF sensor, you are putting twice as much sensor area on the subject. You have gathered double the amount of light with the FF sensor as you are with the APS-C sensor...and it has nothing to do with pixel size. If you downsample the FF image to the same dimensions as the APS-C image, your going to trounce it in both noise levels and detail levels.

The total amount of light gathered is really what matters. Assuming the same sensor size, then the actual pixel size does not really matter all that much. There are things that may result in improved performance of one sensor with one pixels size or another. Improved quantum efficiency is one way. There are also caveats with pixel size. If you want more pixels, that also means more wiring. In FSI sensors, the increased wiring with smaller pixels means there is even less total light sensitive area than with larger pixels. Theoretically, assuming an identical fabrication process is used, our 8mp camera from above will actually have more total photodiode (light sensitive) area than the 32mp sensor. If they both have the same Q.E. then the 8mp sensor will actually perform slightly better due to the slightly greater total photodiode area. This would be the only way I think a 7D II could perform as well as or better (highly unlikely) than the 1D IV. By reducing pixel count significantly, one can increase the total amount of light-sensitive sensor area. I'm not exactly sure where the cutoff point would be...however you would have to pretty drastically reduce the wiring area of the 7D II. You would probably also need to use a process shrink (500nm to 180nm). Another way to do it would be to move to a BSI design. (This all assumes that there is enough wiring in the 1D IV sensor that total light sensitive area is still not greater than the area of an APS-C sensor...if it is, then actually there wouldn't be any way the 7D II could actually perform better.)

In this respect, you are indeed correct about color fidelity and dynamic range...larger pixels do have an edge here. However you are still going to find that greater total sensor area still has a greater impact on those aspects of IQ than larger pixels do in the long run (for example, the D800 has phenomenal color fidelity, however it's pixel size is only marginally larger than the 7D, which has pretty terrible color fidelity in the grand scheme of things...the greater total light gathering capacity, benefited by both higher Q.E. and being FF, of the D800 is it's real edge here.)

Other technology may be employed to increase the total light sensitivity of a sensor pixel. Currently sensors are effectively two dimensional...the only thing that really matters for total charge capacity is the area of the photodiode. Foveon-type sensors stack photodiodes, resulting in an increase in total charge capacity for each pixel. The same technique could theoretically be employed for monochrome and bayer sensors. Blue pixels would be least sensitive, as silicon will filter out most of the bluer wavelengths before they penetrate deeply. Green and red pixels would be most sensitive, allowing for two or three, maybe even four layers of photodiodes. Such technology could be employed in higher megapixel sensors to increase FWC and sensitivity. There is nothing that says the same techniques couldn't be employed with larger pixel sensors, though.

thanks for the explanatation jrista!
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Re: 1d IV vs. 7D II
« Reply #119 on: April 23, 2014, 10:10:45 PM »


There have been strides in sensor technology, however pixel size still dominates the determination of how much noise you have. Smaller pixels will always have more noise, that's a simple matter of physics. We have improved READ noise with better sensor technology, but read noise is only a small contribution to total noise (especially at high ISO)...photon shot noise is the primary source of noise in images. The larger pixels of the 1D IV will always win out against smaller pixels of APS-C sensors. The only way the 7D II could do better is if it had larger pixels than the 1D IV, however that would make it something like a 10mp sensor...highly unlikely.

A smaller pixel generates less read noise, correct. For example, the 7D has 8e- read noise, vs. the 1D X's 35e- read noise. But read noise is a tiny, tiny, tiny contributor to overall noise. The lower FWC means TOTAL noise (including photon shot noise) is higher, because your maximum signal (as dictated by that lower FWC) is lower.

The overall sensor area is what dictates total noise in the image, and in that respect it doesn't really matter what the pixel size is. Smaller sensors have more noise than larger sensors due to their smaller total area/less total light gathered.

Jrista, I'm a little confused by your two statements - which seem at odds with each other, unless I misunderstand them. 

My understanding is noise is determined by the total light gathered by the system, and that is a function of the sensor's area and its quantum efficiency.  That would mean changing the 7D sensor for one which is the same size but has a smaller number of much larger pixels (which otherwise performed the same) wouldn't help with noise, because you wouldn't change the total light gathered by the system.  Larger pixels would presumably have a larger FWC, which might enable more subtle colour/brightness gradation (and perhaps increase dynamic range?), but wouldn't actually reduce noise.

Am I missing something?

That is essentially correct. Pixel size doesn't matter much because you can always downsample, which is effectively the same as either binning or having larger pixels. Let's say you have a 32mp APS-C and a 8mp APS-C. Both sensors have a Q.E. of 50%. Neither sensor has an AA filter. These two sensors are a factor of four difference in pixel size...you can fit four of the 32mp sized pixels into one 8mp sized pixel. If you take the 32mp image and downsample it to 8mp (8000x4000 pixels downsampled to 4000x2000 pixels), the results are the same. The per-pixel noise of the 32mp image is higher, however once downsampled, basic averaging effectively nullifies the increase in noise, and largely nullifies the increase in detail, resulting in nearly the same detail and exactly the same noise as the 8mp sensor. The detail will be slightly higher as you started out with a finer level of detail, and the multi-sampling process of downsampling means that while you are concurrently averaging out noise, you are also compounding the quality of detail in each pixel.

Now, let's say the 8mp camera has 40% Q.E. and the 32mp camera has 80% Q.E. Now the 32mp camera only has noise that is 50% worse than the 8mp, rather than twice as bad. If you downsample the 32mp image to the same dimensions as the 8mp image, the downsampled 32mp image will have less noise and will show the same advantage in detail. It is highly unlikely we will ever see a consumer-grade sensor with 80% Q.E. I've only seen those levels in Grade 1 scientific sensors (the kinds of sensors you find in astrophotography cameras or the stuff they ship up to the Hubble.) We may see sensors with 65% Q.E. or so, however that is only about a half-stop improvement over the ~50% most current sensors have now.

Now, let's say we have two sensors of differing size. Let's say we have a 16mp mp FF sensor, and an 8mp 24x16mm sensor (exactly half the area of the FF sensor, slightly larger than APS-C). Both cameras have exactly the same pixel size. If you frame your subject in one vertical half of the FF sensor with the camera oriented vertically, and crop out the other half, you will have identical results to the 8mp APS-C sensor. If you frame the same subject horizontally using the full area of the FF sensor, you are putting twice as much sensor area on the subject. You have gathered double the amount of light with the FF sensor as you are with the APS-C sensor...and it has nothing to do with pixel size. If you downsample the FF image to the same dimensions as the APS-C image, your going to trounce it in both noise levels and detail levels.

The total amount of light gathered is really what matters. Assuming the same sensor size, then the actual pixel size does not really matter all that much. There are things that may result in improved performance of one sensor with one pixels size or another. Improved quantum efficiency is one way. There are also caveats with pixel size. If you want more pixels, that also means more wiring. In FSI sensors, the increased wiring with smaller pixels means there is even less total light sensitive area than with larger pixels. Theoretically, assuming an identical fabrication process is used, our 8mp camera from above will actually have more total photodiode (light sensitive) area than the 32mp sensor. If they both have the same Q.E. then the 8mp sensor will actually perform slightly better due to the slightly greater total photodiode area. This would be the only way I think a 7D II could perform as well as or better (highly unlikely) than the 1D IV. By reducing pixel count significantly, one can increase the total amount of light-sensitive sensor area. I'm not exactly sure where the cutoff point would be...however you would have to pretty drastically reduce the wiring area of the 7D II. You would probably also need to use a process shrink (500nm to 180nm). Another way to do it would be to move to a BSI design. (This all assumes that there is enough wiring in the 1D IV sensor that total light sensitive area is still not greater than the area of an APS-C sensor...if it is, then actually there wouldn't be any way the 7D II could actually perform better.)

In this respect, you are indeed correct about color fidelity and dynamic range...larger pixels do have an edge here. However you are still going to find that greater total sensor area still has a greater impact on those aspects of IQ than larger pixels do in the long run (for example, the D800 has phenomenal color fidelity, however it's pixel size is only marginally larger than the 7D, which has pretty terrible color fidelity in the grand scheme of things...the greater total light gathering capacity, benefited by both higher Q.E. and being FF, of the D800 is it's real edge here.)

Other technology may be employed to increase the total light sensitivity of a sensor pixel. Currently sensors are effectively two dimensional...the only thing that really matters for total charge capacity is the area of the photodiode. Foveon-type sensors stack photodiodes, resulting in an increase in total charge capacity for each pixel. The same technique could theoretically be employed for monochrome and bayer sensors. Blue pixels would be least sensitive, as silicon will filter out most of the bluer wavelengths before they penetrate deeply. Green and red pixels would be most sensitive, allowing for two or three, maybe even four layers of photodiodes. Such technology could be employed in higher megapixel sensors to increase FWC and sensitivity. There is nothing that says the same techniques couldn't be employed with larger pixel sensors, though.

thanks for the explanatation jrista!

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Re: 1d IV vs. 7D II
« Reply #119 on: April 23, 2014, 10:10:45 PM »