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Messages - jrista

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1051
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 22, 2014, 04:26:21 PM »
Regarding the sensor...very disappointing. Sounds like a re-purposed 70D sensor with a DPAF improvement. I was REALLY, REALLY hoping Canon would really show something impressive on the sensor front with the 7D II. If the camera really does hit the streets with a 20mp sensor, I fully expect it to have the same DR limitations as all of Canon's previous sensors. Extremely disappointing.  :'( Guess we'll have to wait for the 5D IV to see if Canon can actually step up their sensor IQ game or not...which is just...so far down the road...Bleh.

Also worried about the "fine detail"...I really don't want them to start removing AA filters. That is just a dumb trend that photographers like simply because they do not understand the value of an AA filter, or the ease by which AA softening can be sharpened.

+1

it sorta almost leads one to believe that Japanese Canon Fangirls post here where they were claiming that Canon feels they have Canon users trapped enough that it won't matter if the bodies they push out can't keep up as per sensors and even other features at times (still not a hint that they are actually moving any DSLR sensors to new fabs and the panny gets 4k and yet the super new 7D2 which was promised to have revolutionary video and this and that is still 1080p)

and yeah the AA filter-less stuff I am not a big fan of, maybe when we get to 180MP FF or 60MP APS-C or something.

Yeah, we really need sensors to significantly oversample the lens before we can legitimately start dropping AA filters. Otherwise we just end up WITH aliasing, and that's never good.

I was not really interested in the 7D II being a big video DSLR anyway...I don't really know that anyone truly was, you just don't get that cinematic look with a smaller sensor...not without having very wide apertures anyway (like a lot of expensive cinema lenses do).

The thing that I think Canon really needed to nail, and which increasingly appears as they will not, is producing a truly new sensor with a fundamentally new design on a smaller fabrication process size. It just isn't happening. If this thing is still a 500nm transistor part...I mean...WOW. That technology is about fifteen years old!! What is Canon doing? It's one thing to be conservative, but now it's just getting ludicrous...

I have always wondered about this, and you may be the guy to answer. Intel's next series of chips is what, 14nm process? I understand that Intel is purely in the microprocessor business, and Canon has to do a lot more than just optimize processes for sensors, but is there any practical reason why sensor transistors are / should be / need to be on such a different scale? Or is it just a matter of business and not wanting to make the necessary investment to keep shrinking? The fact that intel shrinks every other year has just made me wonder... because clearly there's an advantage to a smaller process.

cost.
no one creates large sensors using the latest technology - the A7R / D810E sensor for instance is on 180nm.  which is speculated to the be the same as the 70D sensor. D700, D4, etc were even on larger than that (350nm to 250nm)

the toshiba sensor uses 65nm and sony was looking at and just starting to use 90nm for it's APS-C sensors, but unless you're talking the smart phone / compact sensors - there's just no benefit to the smaller geometries over the cost of production with the pixel granularity where it is.

canon's current line of lithography systems can produce chips under 90nm - far exceeding even really what is required by sensors - so it's not as if canon can't if they feel they have to.  also to add to that, canon now has the equipment to product down to under 10nm geometries.

To be honest, people are humping on this as the core reason - not really.  and most of them don't have a freaking clue, but all of a sudden turn into electronic and chip designers (not to mention camera designers too).  canon certainly has a problem "downlevel" from the pixel - but their QE from their current 70D isn't that much off than the D5100's QE and even cutting the pixels in half they improved the QE by 10% over the 7D sensor level spec.

Your partly right, but your largely missing the point. A 500nm transistor is actually HUGE by todays standards. Think about it, that is half a micron. For a pixel that is surrounded by half-micron transistors, that is a FULL micron off all side of the pixel. A 4µm pixel is then only capable of, at most, a 3µm photodiode. The full size of the pixel itself is 1.78x larger in area than the photodiode. However, if you move to a 180nm process, your losing less than half a micron in total. That means the photodiode can be 3.6µm in size. The pixel is only 1.2x larger in area than the photodiode. Your photodiode area has increased by a factor of 1.5x, which reduces noise by 1.2x. That is significant. It's a stop gained in noise performance.

However, the REAL point about moving to a smaller transistor size is the ability to put more logic on the sensor die. At 500nm, Canon would have to make the sensor die itself quite a lot larger in order to move all the ADC logic onto the sensor itself, and make it column-parallel. At 180nm or better 90nm, they could move the ADCs on-die and need less than half, maybe less than one quarter, of the die space that would be necessary to do that with a 500nm process. Yield would remain high, so the cost of moving ADC onto the sensor would be much lower in the long run. THAT is the real point of moving to a smaller process. To allow more logic to be placed on the sensor die itself. The biggest gain there would be allowing full blown, high performance CP-ADC (and, maybe, also employ some of the other patents Canon has, such as dual scale ADC, power decoupling, etc.)

There is also a significantly greater per-pixel transistor requirement for stacked pixel designs. Canon recently released a patent for a five-layer sensor design. I honestly don't know how they would pull that off with a 500nm process. Not without a very low fill factor which would push noise levels sky high. However, with a 90nm fabrication process, creating a five layer sensor would be much, much easier, without running into serious problems with noise.

1052
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 22, 2014, 04:08:48 PM »
Actually, the use of Dual DIGIC 6 makes me really think that there is NO more magic cooked into the sensor, and that all the "magic" is happening after the signal is pulled OFF the sensor. It's probably roughly the same sensor that employs a slightly new DPAF design, and probably has a very weak or no AA filter, but is otherwise unchanged from the 70D. DIGIC 6, which actually came out before Sony BionzX, actually has a LOT of the same capabilities, and is the primary reason the IQ on their smaller form factor cameras is good. They really cook the signal coming off the sensor.

Since DIGIC 6 supposedly allows frame rates to 14fps and 60fps video, why would they need two of them?  Dual pixel works okay on the 70D with just one DIGIC 5+.

From what I've read about DIGIC 6, a lot of the processing power is dedicated to image processing, not just your basic readout and write to RAW. I would be willing to bet that any IQ improvement in the 7D II comes from the pair of DIGIC 6 chips. As for frame rate, as I mentioned in my original post, Canon probably wants to reserve frame rates greater than 10fps for their premium 1D line, which is understandable IMO.

1053
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 22, 2014, 04:06:38 PM »
If Canon doubled Q.E., then high ISO would be better for sure...but I would be surprised if Q.E. on this thing is over 50%.

sensors reach 90%+ QE... i would be suprised when the 70D does not.

LOL. Extremely high grade sensors that cost a TON of money reach 90% Q.E. The DSLR camera with the highest Q.E. on the market right now has 60% Q.E. The 70D has 45% Q.E. There is absolutely NO WAY that Canon sensors will suddenly hit 90% Q.E. You have to spend at least $5000 on a thermally regulated CCD camera to get over 90% Q.E., and then, it IS a CCD, and those sensors are usually non-anti-blooming CCDs (so charge from each pixel spills over into neighboring pixels when they reach their capacity).

Getting that much quantum efficiency is not easy. It requires very high grade materials and careful construction. Canon has apparently not changed their manufacturing process, so seeing a 5% increase in Q.E. over the 70D sensor in the 7D II would be about as much as I could expect.

1054
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 22, 2014, 03:59:04 PM »
Couple of things.

1. Build quality was not mentioned. Only stated that it didn't have the 1D style top plate.

2. "Fine Detal" CMOS is being read as removing the AA filter. The bit above the specs state that the sensor does have new technology. Removing an AA filter is NOT new tech.

3. Confused personally by the ISO 16,000 upper limits which is 1 1/3 stops. Odd but I guess not unbelievable.

4. Spot metering is 1.8% To me that does help the sports segment some on a dark field.

5.  Dual Digic 6 . . . . . . . makes me think/hope their may be a bit more magic cooked into the sensor than a mild 70D upgrade

Actually, the use of Dual DIGIC 6 makes me really think that there is NO more magic cooked into the sensor, and that all the "magic" is happening after the signal is pulled OFF the sensor. It's probably roughly the same sensor that employs a slightly new DPAF design, and probably has a very weak or no AA filter, but is otherwise unchanged from the 70D. DIGIC 6, which actually came out before Sony BionzX, actually has a LOT of the same capabilities, and is the primary reason the IQ on their smaller form factor cameras is good. They really cook the signal coming off the sensor.

1055
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 22, 2014, 03:55:35 PM »
70D native top iso 12800
7D - 16000

If correct doesn't sound like 'just' a 70D with AA removed to me??

There really isn't anything special about moving up to 16000 "native", especially if it's the same sensor as the 70D. It won't be any better than a digital push...its going to be using the downstream analog amp anyway for that, which is really no better.

If Canon doubled Q.E., then high ISO would be better for sure...but I would be surprised if Q.E. on this thing is over 50%.

1056
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 22, 2014, 03:52:47 PM »
Regarding the sensor...very disappointing. Sounds like a re-purposed 70D sensor with a DPAF improvement. I was REALLY, REALLY hoping Canon would really show something impressive on the sensor front with the 7D II. If the camera really does hit the streets with a 20mp sensor, I fully expect it to have the same DR limitations as all of Canon's previous sensors. Extremely disappointing.  :'( Guess we'll have to wait for the 5D IV to see if Canon can actually step up their sensor IQ game or not...which is just...so far down the road...Bleh.

Also worried about the "fine detail"...I really don't want them to start removing AA filters. That is just a dumb trend that photographers like simply because they do not understand the value of an AA filter, or the ease by which AA softening can be sharpened.

+1

it sorta almost leads one to believe that Japanese Canon Fangirls post here where they were claiming that Canon feels they have Canon users trapped enough that it won't matter if the bodies they push out can't keep up as per sensors and even other features at times (still not a hint that they are actually moving any DSLR sensors to new fabs and the panny gets 4k and yet the super new 7D2 which was promised to have revolutionary video and this and that is still 1080p)

and yeah the AA filter-less stuff I am not a big fan of, maybe when we get to 180MP FF or 60MP APS-C or something.

Yeah, we really need sensors to significantly oversample the lens before we can legitimately start dropping AA filters. Otherwise we just end up WITH aliasing, and that's never good.

I was not really interested in the 7D II being a big video DSLR anyway...I don't really know that anyone truly was, you just don't get that cinematic look with a smaller sensor...not without having very wide apertures anyway (like a lot of expensive cinema lenses do).

The thing that I think Canon really needed to nail, and which increasingly appears as they will not, is producing a truly new sensor with a fundamentally new design on a smaller fabrication process size. It just isn't happening. If this thing is still a 500nm transistor part...I mean...WOW. That technology is about fifteen years old!! What is Canon doing? It's one thing to be conservative, but now it's just getting ludicrous...

1057
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 22, 2014, 03:23:13 PM »
65 AF points “All Cross-type”. Dual cross on the center point.

I'd like to know how many of those are f/8 AF points.

Me too!

1058
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 22, 2014, 02:52:04 PM »
Hmm, very interesting. The first thing that pops out at me is the 65 AF pints "All Cross Type". That is really impressive! I never expected that...I figured it would be closer to 41 AF points.

Bummed a bit about the mixed use of CF and SD. I really wish Canon would stop doing that...dual cards of different types are useless...I'd much rather have dual CF so I wouldn't experience any speed discrepancies.

I'm not surprised by 10fps...it seemed a bit far fetched that the camera would get 12fps. Canon has to keep some things "premium", it makes sense to keep the fastest frame rates locked to the 1D line. I'm also not surprised about Dual DIGIC 6...although I had hoped for DIGIC 7 along wit a real high resolution, high DR sensor.

Regarding the sensor...very disappointing. Sounds like a re-purposed 70D sensor with a DPAF improvement. I was REALLY, REALLY hoping Canon would really show something impressive on the sensor front with the 7D II. If the camera really does hit the streets with a 20mp sensor, I fully expect it to have the same DR limitations as all of Canon's previous sensors. Extremely disappointing.  :'( Guess we'll have to wait for the 5D IV to see if Canon can actually step up their sensor IQ game or not...which is just...so far down the road...Bleh.

Also worried about the "fine detail"...I really don't want them to start removing AA filters. That is just a dumb trend that photographers like simply because they do not understand the value of an AA filter, or the ease by which AA softening can be sharpened.

1059
Technical Support / Re: Another my Stupid question = Sensor Sizes
« on: August 22, 2014, 02:16:29 PM »
@sagittariansrock: There is a difference in your explanation than the standard one: Your explanation does not utilize the full sensor area of larger sensors. Your explanation is based on the subject filling the same absolute area of the sensor, regardless of the total sensor area. That is the reach-limited argument. That is the ONE AND ONLY case where smaller sensors can achieve the same image quality as a larger sensor.

That is exactly right. Except, here we are discussing the capacity of a pixel to collect light, which is why this scenario should be used- that is, where the incident light is exactly the same in terms of intensity and quality.

The fair comparison is when your subject is framed the same, which means that for progressively larger sensors, a greater absolute area of sensor covers the subject. In that case, everything Orangutang, Lee Jay, and myself have stated is true. There is no circumstance where smaller sensors, regardless of their pixel size, can ever outperform a larger sensor.

I don't know if I will call it a fair comparison, but I can call it a real-world comparison. And as I said before I am sure everyone agrees with what you, Lee Jay and Orangutang are contending here- larger sensors have better IQ. No way can a smaller sensor collect the same amount of light. Except that is not the point here- the point is, would a smaller pixel collect less light than a larger pixel? Yes. Would a pixel collect the same amount of light whether its part of a large sensor or a small sensor? Of course!
This is why I said you all are disputing each other while everyone being right at the same time ;)

I'm sorry, but I beg to differ, given that this is the title of the thread:

Another my Stupid question = Sensor Sizes

And this is the actual question asked:

Dear Teachers and Friends.
Well, Yes, I can take a SoSo-or Good Photos, Because of I take the photos so long time. But for the High Tech of Digital Photography, I almost know nothing a bout this New Technology.
My Stupid Question are :
1)  Are the Size of the Sensor Matter ?---Or the MP. count are matter ?
Such As  the Tiny Sensor on Nokia Lumia 1020 = 41 MP, compare to Canon 1DX  FF = 18.1 MP, and Canon 5D MK II FF = 22.3 MP
2) If the Sensor are same Size and Same MP-----The  Camera company are matter or not that can claim , My Ca--- are Sharpper than your Ni--- ???
3) What Make the Same size of Sensor ( of this Company ) to be better than another Company Sensor ?
Thanks for your Answers, That will make me up to date of new Technology.
Have a great day, Sir/ Madam.
Surapon

The question is whether the size of the sensor matters or not. So, the point here is NOT about whether smaller pixels will collect more light...the point, very specifically, is whether differences in sensor size matter. Within the scope of the original question asked by Surapon, the proper context to discuss comparisons in is a normalized context...on in which the subject is framed identically, and, to be truly fair, where all the output images are resampled to the same dimensions.

That is the standard context for comparing images. It's the requirement of using ISO 12233 test charts, the standard test chart that pretty much every lens and camera tester, with maybe the exception of DXO, use to compare the IQ of different camera systems, that all framing be identical regardless of sensor size.

The reach-limited comparison is not wrong, however it does place a handicap on larger sensors, a handicap that becomes increasingly severe the larger the discrepancy between the small sensor and the large sensor. In a reach limited scenario, I'd rather have an APS-C sensor, or maybe even smaller, with a small pixel, than a FF sensor with large pixels. But when I have the option of getting closer, or using a longer lens, I'll take the FF every time. I'd certainly rather have more pixels in the FF than fewer, as I can always downsample if I need less noise...but when I have the option of framing identically, larger sensors trounce smaller sensors.

1060
Technical Support / Re: Another my Stupid question = Sensor Sizes
« on: August 22, 2014, 01:49:24 PM »
@sagittariansrock: There is a difference in your explanation than the standard one: Your explanation does not utilize the full sensor area of larger sensors. Your explanation is based on the subject filling the same absolute area of the sensor, regardless of the total sensor area.

That is the reach-limited argument. That is the ONE AND ONLY case where smaller sensors can achieve the same image quality as a larger sensor. However, it SEVERELY handicaps the larger sensors. The fair comparison is when your subject is framed the same, which means that for progressively larger sensors, a greater absolute area of sensor covers the subject. In that case, everything Orangutang, Lee Jay, and myself have stated is true. There is no circumstance where smaller sensors, regardless of their pixel size, can ever outperform a larger sensor.

There are real-world use cases where a limited reach is an actual problem. I already posted a topic on that, demonstrating the differences between a 5D III and a 7D, and the 7D does indeed maintain the IQ edge (I really need to try that on a day with better seeing, or find a good terrestrial subject to compare.) But in the "normative" case, you buy a larger sensor to use the greater area to get better IQ. I mean, that's the entire point. That's where improved IQ comes from.

Before I found the equivalence article, I used to think the same thing...that pixel size mattered. But it simply doesn't. Not at lower and midrange ISO settings anyway. At really high ISO settings, then the game does change a bit. Spatially, information in an incomming wavefront is sparser when your working in really low light, or at a really small aperture, or any other circumstance where you NEED something like ISO 12800 or higher. Sparser data ultimately renders smaller pixels useless, since you just don't have complete enough information to render a whole picture. Then, pixel size really does start to matter. Or, conversely, downsampling your image becomes more important to reducing noise.

For the ultra high ISO use cases, I would actually love to see Canon create a sensor that had some kind of dynamic binning. At low ISO, use full maximum resolution, then have a configurable option to switch to a hardware binning mode of 2x2 for say ISO 6400 through 26500 and maybe even have an additional 4x4 binning option for ISO 51200 through 400k or whatever. I think that would be awesome, since you can't really get clean high resolution at ultra high ISO anyway.

However, fundamentally, in a fair or normative situation where your utilizing all the sensor area you can (i.e. assuming identical framing) and and for the same aperture used, larger sensors gather more light per subject area. If you read the equivalence article, when he gets down into the myths, he clearly covers how with a larger sensor, you need to use a narrower aperture on larger sensors for a given FoV to make image quality equivalent. For 80mm f/4 FF, you would need 50mm f/2.5 APS-C (that is 4 divided by 1.6, the scale factor between FF and Canon APS-C...it does not take pixel size into account at all), 40mm f/2 4/3rds:

http://www.josephjamesphotography.com/equivalence/#1

Quote
1) f/2 = f/2 = f/2

This is perhaps the single most misunderstood concept when comparing formats.  Saying "f/2 = f/2 = f/2" is like saying "50mm = 50mm = 50mm".  Just as the effect of 50mm is not the same on different formats, the effect of f/2 is not the same on different formats.

Everyone knows what the effect of the focal length is -- in combination with the sensor size, it tells us the AOV (diagonal angle-of-view).  Many are also aware that  f-ratio affects both DOF and exposure.  It is important, however, to understand that the exposure (the density of light falling on the sensor -- photons / mm²) is merely a component of the total amount of light falling on the sensor (photons):  Total Light = Exposure x Effective Sensor Area, and it is the total amount of light falling on the sensor, as opposed to the exposure, which is the relevant measure.

Within a format, the same exposure results in the same total light, so the two terms can be used interchangeably, much like mass and weight when measuring in the same acceleration field.  For example, it makes no difference whether I say weigh 180 pounds or have a mass of 82 kg, as long as all comparisons are done on Earth.  But if makes no sense at all to say that, since I weigh 180 lbs on Earth, that I'm more massive than an astronaut who weighs 30 lbs on the moon, since we both have a mass of 82 kg.

The reason that the total amount of light falling on the sensor, as opposed to the density of light falling on the sensor (exposure), is the relevant measure is because the total amount of light falling on the sensor, combined with the sensor efficiency, determines the amount of noise and DR (dynamic range) of the photo.

For a given scene, perspective (subject-camera distance), framing (AOV), and shutter speed, both the DOF and the total amount of light falling on the sensor are determined by the diameter of the aperture.  For example, 80mm on FF,  50mm on 1.6x, and 40mm on 4/3 will have the same AOV (40mm x 2 = 50mm x 1.6 = 80mm).  Likewise, 80mm f/4, 50mm f/2.5, and 40mm f/2 will have the same aperture diameter (80mm / 4 = 50mm / 2.5 = 40mm / 2 = 20mm).  Thus, if we took a pic of the same scene from the same position with those settings, all three systems would produce a photo with the same perspective, framing, DOF, and put the same total amount of light on the sensor, which would result in the same total noise for equally efficient sensors (the role of the ISO in all this is simply to adjust the brightness of the LCD playback and/or OOC jpg).

Thus, settings that have the same AOV and aperture diameter are called "Equivalent" since they result in Equivalent photos.  Hence, saying f/2 on one format is the same as f/2 on another format is just like saying that 50mm on one format is the same as 50mm on another format.

1061
Technical Support / Re: Another my Stupid question = Sensor Sizes
« on: August 22, 2014, 04:15:44 AM »
Scenario 1: Normalize for pixel size
We have a camera that we can swap sensors on. We mount a 100mm lens to that camera.
All of our sensors use the exact same technology and have the exact same 0.01mm by 0.01mm pixels.

FF sensor    - 36x24 mm,     3600x2400 (8.60Mp), 20.0 degree fov
APS-C sensor - 22.2x14.8 mm, 2220x1480 (3.29Mp), 12.3 degree fov
4/3 sensor   - 17.3x13.3 mm, 1730x1330 (2.30Mp),  9.6 degree fov
1/2.3 sensor - 5.76x4.29 mm,  576x429  (0.25Mp),  3.2 degree fov

In this case, each sensor will have the exact same resolving power. Each sensor will have the exact same IQ, the ISO performance and the noise performance will be identical. In this case, what sensor size buys you is the number of pixels and the field of view.

The crop value is what the focal length would have to be to get the same field of view from a FF camera.
FF - crop value is 1
APS-C - crop value is 20/12.3 or 1.62
4/3 - crop value is 20/9.6 or 2.08
1/2.3 - crop value is 20/3.2 or 6.25

to look at what the equivalent FF lens length would be for the same field of view...
APS-C, 100mm has the same field of view as 162mm on FF
4/3,   100mm has the same field of view as 208mm on FF
1/2.3, 100mm has the same field of view as 625mm on FF


Scenario 2: normalize for the field of view (20.0 degrees)
FF sensor    - 36x24 mm,     3600x2400 (8.60Mp), 100mm lens
APS-C sensor - 22.2x14.8 mm, 2220x1480 (3.29Mp), 61.7mm lens
4/3 sensor   - 17.3x13.3 mm, 1730x1330 (2.30Mp), 48.1mm lens
1/2.3 sensor - 5.76x4.29 mm,  576x429  (0.25Mp), 16.0mm lens

We now have the same field of view from the cameras. Each sensor will have the exact same IQ, the ISO performance and the noise performance will be identical.
In this case, what sensor size buys you is the number of pixels and over the same field of view, the FF camera has far greater resolving power.


Scenario 3: Normalize for the number of pixels.
In this case, the lens stays the same but the size of the pixels varies to keep a constant 8.6Mpixels on the sensor.

FF sensor    - 36x24 mm,     0.0100mm pixels, 20.0 degree fov
APS-C sensor - 22.2x14.8 mm, 0.0062mm pixels, 12.3 degree fov
4/3 sensor   - 17.3x13.3 mm, 0.0048mm pixels,  9.6 degree fov
1/2.3 sensor - 5.76x4.29 mm, 0.0016mm pixels,  3.2 degree fov

We now have smaller pixel sizes on the smaller sensors, and as they get smaller ISO performance drops and noise rises. In this case, the smaller sensors have greater resolving power than the larger sensors.

In summary:
Larger pixels give you better ISO performance and lower noise.
Smaller pixels give you more resolving power ON THE SAME LENS.
Sensor size affects the field of view.

The balance you select between the three is what determines the performance of your camera.

The only thing I would dispute is the regular use of "each sensor will have the exact same IQ". Hate to say it, but that is wrong...at least, so long as another required factor is not specified. :P Sensor size is the primary factor that controls "image quality", not pixel count, not pixel size. You could have twice the Q.E. on a smaller sensor, and the only one that would then only EQUAL the IQ of the larger sensor is the one that is exactly half it's size. A 4/3rds or 1/2.3 could never compare to the IQ of a FF sensor, not even with double the Q.E.

Now, the statement about equal IQ would be true...IF the aperture was specified. The 100mm lens on a FF sensor has to be using a smaller aperture than the 61.7mm lens, by a factor of the differences of the sensor diagonals. If the 61.7mm lens is f/2.8, then the 100mm lens should be f/4.5. THEN, and ONLY THEN, would "each sensor have the exact same IQ." You have to use a smaller aperture to normalize the amount of light reaching the sensor. Otherwise, one has to assume the same aperture. A 100mm lens on FF produces the same FoV as a 61.7mm lens on APS-C, however if they are both f/2.8, the FF sensor is without question gathering more light.

Equivalence. Aperture matters here.

I've said this so man times...but, I think Orangutan is the only one who actually heard it. So I'll just quote his answer:

I'm no expert on this, so I'll refer you to: http://www.clarkvision.com/articles/does.pixel.size.matter and to jrista's various write-ups.

Scenario 2: normalize for the field of view (20.0 degrees)
FF sensor    - 36x24 mm,     3600x2400 (8.60Mp), 100mm lens
APS-C sensor - 22.2x14.8 mm, 2220x1480 (3.29Mp), 61.7mm lens
4/3 sensor   - 17.3x13.3 mm, 1730x1330 (2.30Mp), 48.1mm lens
1/2.3 sensor - 5.76x4.29 mm,  576x429  (0.25Mp), 16.0mm lens

We now have the same field of view from the cameras. Each sensor will have the exact same IQ, the ISO performance and the noise performance will be identical.
In this case, what sensor size buys you is the number of pixels and over the same field of view, the FF camera has far greater resolving power.

To me this is the only case that matters -- the question is irrelevant and misleading unless we're talking about identically-framed shots.  With identically framed shots, a larger sensor will collect more light from the overall field of view (and therefore per-unit-area of the scene), even if the smaller sensor has larger pixels.  With our hypothetical identical technology, a smaller sensor with larger pixels simply cannot collect the same amount of light as a larger sensor.  Compare this to 35mm film vs MF film using identical emulsion.  To what degree that's important depends on the lighting of the scene.  Higher pixel density may give higher resolution (if the lens allows it).

This is EXACTLY CORRECT. The only thing that really matters in the end, assuming all the sensors use the same technology, is TOTAL light gathered. More light, less noise. It's as simple as that. Pixel size doesn't really matter from a noise standpoint. Smaller pixels in the SAME sensor size mean you get more resolution, that does increase IQ...but smaller pixels in a smaller sensor DO NOT mean better IQ....they just mean more resolution, but with worse IQ.

This is equivalence. This scientific concept is documented very, very, very thouroughly here:

http://www.josephjamesphotography.com/equivalence/

If you still doubt, please, read the article on equivalence linked above. It's really not that complicated of a concept.

I'm no expert on this, so I'll refer you to: http://www.clarkvision.com/articles/does.pixel.size.matter and to jrista's various write-ups.

Scenario 2: normalize for the field of view (20.0 degrees)
FF sensor    - 36x24 mm,     3600x2400 (8.60Mp), 100mm lens
APS-C sensor - 22.2x14.8 mm, 2220x1480 (3.29Mp), 61.7mm lens
4/3 sensor   - 17.3x13.3 mm, 1730x1330 (2.30Mp), 48.1mm lens
1/2.3 sensor - 5.76x4.29 mm,  576x429  (0.25Mp), 16.0mm lens

We now have the same field of view from the cameras. Each sensor will have the exact same IQ, the ISO performance and the noise performance will be identical.
In this case, what sensor size buys you is the number of pixels and over the same field of view, the FF camera has far greater resolving power.

To me this is the only case that matters -- the question is irrelevant and misleading unless we're talking about identically-framed shots.  With identically framed shots, a larger sensor will collect more light from the overall field of view (and therefore per-unit-area of the scene), even if the smaller sensor has larger pixels.  With our hypothetical identical technology, a smaller sensor with larger pixels simply cannot collect the same amount of light as a larger sensor.  Compare this to 35mm film vs MF film using identical emulsion.  To what degree that's important depends on the lighting of the scene.  Higher pixel density may give higher resolution (if the lens allows it).

This is something that I have had many discussions about. My understanding from talking to more experienced togs is that the pixel size is what affects light gathering capability, not the sensor size.
A larger sensor (say FF vs APS-C) will capture more light because obviously it is bigger. However, the intensity of light reaching the pixels on each sensor will be identical for a given lighting scenario. Therefore, the light reaching the sensor "per-unit-area of the scene" will be identical. The light entering the pixels will not be identical, however.
So how does sensor size alter exposure? For example: Generally F/4 on FF means you will require F/2.8 for the same exposure on APS-C but from what I have been lead to believe that is due to pixel size, not sensor size.
Thoughts?

You are incorrect. Pixel size affects per-pixel dynamic range and per-pixel noise. That affects what you see when editing a RAW image at 100%. Larger pixels do gather more light. But larger pixels stuffed into the same area as smaller pixels (i.e. larger vs. smaller pixels in a full frame sensor) don't actually change the final noise levels of an identically framed subject. Smaller pixels affect the final detail levels, however noise is ultimately relative to the whole sensor frame. And I have to stress...for identically framed subjects. There is no point to using a larger sensor if you are not framing the same. You don't gain any of the benefits of using a larger frame if your not filling it just as much a you would fill a smaller frame. That means either getting closer to your subject (which full frame cameras allow, it's one of their primary attractions for a lot of photographers), or it means your going to be using a longer lens.

Now, the following assumes the same ISO setting for every circumstance. Let's just assume ISO 100. It also assumes the same aperture is used. Let's say f/4.

Two FF sensors, one with 10µm pixels with a 100ke- FWC and one with 5µm with 25ke- FWC pixels, framing a portrait of a woman, are both gathering the same amount of total light when the woman's head fills the frame. Bin 4x5µm pixels together, and you combine four distinct 25ke- charges together to create...what? Yup, one single 100ke- charge in an effective 10µm pixel. Similarly, combining four pixels together reduces the individual noise levels of each pixel by...what? Yup, the square root of the number of pixels combined...SQRT(4) is 2. Noise levels drop by a factor of two...they are cut in half. This is effectively the same as downsampling the larger image that is produced by the sensor with smaller pixels to the same dimensions as the smaller image that is produced by the sensor with larger pixels. Same difference...the noise of each small image pixel is interpolated...averaged together...to produce a less noisy output pixel.

So, while noise PER PIXEL is less with larger pixels...your actually LOSING something with larger pixels. Your losing resolution. With smaller pixels...you can always just average them together, and end up with the same amount of noise as you would have gotten if you'ed sacrificed resolution to have larger pixels. However, downsampling also enhances detail, so a downsampled image taken with a sensor the same size but with smaller pixels is pretty much always going to look better than a sensor (of the same size) with larger pixels.

Pixel size does not change the TOTAL amount of light gathered by a sensor. It just divides the incoming real image signal into smaller parts. Each smaller part has more RELATIVE noise, because the noise is relative to a maximum signal level of 25ke- rather than relative to 100ke-. Combine four pixels together, and now your noise is relative to 100ke-. It's equivalent. Sensor size is the primary factor that affects image quality, assuming all other factors are equal (i.e. same fabrication process, same Q.E., same ISO, same exposure).

Let's say you have a FF 10µm pixel sensor and a 5µm pixel sensor that is exactly 1/4 the FF sensor size (18x12mm). These two sensors have the exact same pixel count, and the exact same relative pixel size (relative to the size of the sensor.) According to Don and Robbinzo's theory, the IQ of these two sensors would be identical. Which one is going to produce better IQ? The one with bigger pixels? Well, yes. But is it because of bigger pixels? What happens if we make the FF sensor use 5µm pixels as well? Now it has four times the pixels as the 18x12mm sensor. Will it's image quality drop? How do you know whether it's IQ will drop or not?

Well, think of it this way. The large pixels of the FF sensor are now one quarter as large...however so long as you keep the subject framed the same, for every one pixel that you used to place on the subject before, you now have four pixels. However, with the 18x12mm sensor...you still have just one pixel. Worse, that one pixel represents an area four times larger with the smaller sensor than it does with the FF sensor. So technically speaking, the FF sensor with 5µm pixels is putting a total of 16 pixels onto the same absolute area of the subject as every one pixel with the 18x12mm sensor. You could halve the pixels of the 18x12mm sensor...but it's the same deal. Finer resolution relative to it self, but nothing changes in terms of the difference between the FF sensor and the 18x12mm sensor. The subject is still framed the same...and the same relative differences exist. For any given absolute area of the subject, the larger sensor will always use a larger area of the sensor to resolve that area of the subject than the smaller sensor.

No matter how you slice it, no matter how much you either make pixels smaller or larger...fundamentally, IQ is related to total sensor area, not pixel size. The only thing that is really related to pixel size is resolving power...the ability to delineate elements of detail. Smaller pixels delineate finer elements of detail then larger pixels. That's it. So, having to use f/4 on FF and f/2.8 on APS-C has everything to do with sensor size, and nothing to do with pixel size! Otherwise, how could that ratio work? We have had APS-C sensors with pixel sizes ranging from 10µm down through 3.8µm released over the last 10 years. However, people have been saying that same thing, that you have to use f/4 on FF and f/2.8 on APS-C with FoV-equivalent lenses to get the same IQ for the same time period. Actually, they have been saying it for a whole hell of a lot longer, back in the film days, when we had APS-C film vs. 35mm film. And before that, when we had various medium format films vs. large format films. And even among large format films, say 4x5 vs. 8x10! This debate has been raging on for decades, the better part of a century! If it was the pixel size that mattered...how could that statement have remained true for a decade? For decades? For nearly 100 years?!? Because it's not the pixel size that matters...it's the sensor size that matters!  ;)

1062
Lenses / Re: Development Announcement of a New 800mm f/5.6L IS II [CR1]
« on: August 20, 2014, 04:35:22 PM »
Also, when you get into these extremes, you need to be shooting in cold, clean alpine air, or humidity and other environmental conditions will wreck your image.

Depends on what your shooting. I have no need to shoot wildlife at 1200mm, 600mm is actually more than plenty. Sometimes deer and the like get so close out of curiosity that I can't even get a shot.

With waders and other larger, shy birds, that might be a problem. Depends on whether where you live is humid or not. I live in Colorado. We've had some hot years, but most of the time it's not blistering (80 degrees or cooler) and it's pretty dry up here in general. The only time I've had problems with water vapor being a problem was when the temperature was near or over 100 degrees...then it's a problem even at 600mm.

The real benefit of 1200mm comes into play when your photographing small birds. With just the 600mm, even at a relatively close distance, with a full frame, they are quite small. Moving to 1200mm with passerines isn't because they are far away...it's just to increase their size relative to the frame, but your still relatively close. More than close enough that water vapor in the air isn't going to be a problem between lens and subject (it might wreck your background boke...but that's a whole different deal.)

1063
Lenses / Re: Development Announcement of a New 800mm f/5.6L IS II [CR1]
« on: August 20, 2014, 01:45:04 PM »
For me, the maximum focal length that still allows autofocus is important.
I have the 600 II with a 5D3 so can use autofocus at 1200mm at f/8 with a 2x extender. The 800mm f/5.6 can only autofocus with the 1.4 extender (1120 mm at f/8). All things considered, I like the flexibility offered by the 600 f/4 versus the 800 f/5.6.

Same here, I like being able to use 1200mm f/8 when I need to, and for a lot of the birds I shoot, it's necessary.

However, I do suspect that the 800/5.6 + 1.4x will produce better IQ than the 600/4 + 2x...and for some people, having that extra bit of IQ is everything. I know of some bird photographers who refuse to use teleconverters, ever, period, because they don't like how it affects their sharpness.

1064
Lenses / Re: Development Announcement of a New 800mm f/5.6L IS II [CR1]
« on: August 20, 2014, 12:16:09 PM »

These lenses, now that they are so light, are eminently hand holdable. I hand hold my 600/4 II all the time, with and without a 1.4x TC. The IS is invaluable for hand-held work like that. Even when used on a tripod, there are things, like vibrations caused by wind, that IS is still useful for.

I thought all the whites version II had an detection inside to find out if they are used on a tripod, and if that's the case then IS would be switched off. Or am I wrong ?

The "tripod sensing" really just checks for a certain minimal mount of vertical shake, and if the shake is below that threshold, it throttles IS. If you have wind vibrating the lens, that usually pushes the shake above that threshold, and IS will still operate. Personally, I just use IS Mode 3, and I've never changed it. It works when I need it to, and that's all that matters.

1065
Lenses / Re: Development Announcement of a New 800mm f/5.6L IS II [CR1]
« on: August 20, 2014, 11:18:51 AM »
What sense does it make to put IS on such a big lens that would likely always be mounted on a tripod where IS is not needed? Or even not recommended?  Is use of a monopod assumed to be the most frequent user choice?   Certainly hand-held, where IS would be most helpful, doesn't seem practical because of quick fatigue with such a big lens.

These lenses, now that they are so light, are eminently hand holdable. I hand hold my 600/4 II all the time, with and without a 1.4x TC. The IS is invaluable for hand-held work like that. Even when used on a tripod, there are things, like vibrations caused by wind, that IS is still useful for.

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