6D Mark II Owners Unite! Discuss and post Photos!

John Sheehy wrote in post #18762826
Depending on pixel and microlens size, FSI sensors lose some of the extra light you get when you open the lens aperture so that the f-number goes low. IOW, instead of getting 2 stops more light at f/1.4 than at f/2.8, you might only get 1.5 stops more light getting into the photosites. The camera fakes the missing light collection of 0.5 stops by multiplying the RAW data values. This approach serves the exposure triangle, but fails the RAW user who loses 0.5 stops of DR and highlights!

If the 6DII did not do this, then f/1.4 at 1/4000 might not clip sunlit whites! Canon only cares about their own internal standards and protocols; not your ability to shoot at f/1.4 in sunlight!

You seem to be mixing things up here.
Back illumination was/is originally used to increase sensitivity in low illumination situations, such as microscopy. Under bright light, how is there much of a difference? The same proportion of light is being lost at f/1.4 and f/1.8 under bright conditions so long as the sensor isn't reaching saturation.

Under low illumination, I could understand such a statement since the electronics and "wiring" block or reflect a lot of the light. The quantum efficiency of of back illuminated sensor is around 90% compared to 60 for a front illuminated sensor.

http://micro.magnet.fs​u.edu …ts/quantumeffic​iency.html

Capn Jack wrote in post #18767542
You seem to be mixing things up here.
Back illumination was/is originally used to increase sensitivity in low illumination situations, such as microscopy.

Under bright light, how is there much of a difference? The same proportion of light is being lost at f/1.4 and f/1.8 under bright conditions so long as the sensor isn't reaching saturation.

Under low illumination, I could understand such a statement since the electronics and "wiring" block or reflect a lot of the light. The quantum efficiency of of back illuminated sensor is around 90% compared to 60 for a front illuminated sensor.

http://micro.magnet.fs​u.edu …ts/quantumeffic​iency.html

That article doesn't even mention anything about f-numbers.

There is no practical reciprocity factor with digital cameras. The amount of light flux is not the issue. It is the percentage that gets through from exposure successfully to capture in the photosites at a fixed linear rate at each f-number. That percentage varies with FSI sensors quite a bit between f/2.8 and f/1.4, with smaller pixels. Take any FSI APS-C or FF camera, and mount a manual aperture lens on it. Meter for f/2.8 in M mode, and then take a series of images with the same "exposure" predicted by the exposure triangle at all the lower f-number clicks with the corresponding shutter speed, such as f/2.8 1/500, f/2.5 1/640, f/2.2 1/800, etc, down to f/1.4 1/2000 or further, and the images will become progressively darker. With a 6D or 1Dx, with bigger pixels, you may not see the darker images until about f/2, maybe f/2.2 or 2.5 for the 30 and 26MP FF cameras. If you don't have a manual aperture lens, you can do a simpler, less elegant test by shooting an f/1.4 lens wide open in M mode, then take the same shot again, this time with the lens unscrewed just enough to lose lens communication. The latter will be significantly darker, and it will have more highlight headroom, which the firmware clipped away when proper protocol was used in the first image.

It won't show the exact optical effect, but you can see how the camera attempts to compensate for it by shooting black frames with the lens cap at all f-numbers f/3.2 and below, and at some point the blackframe noise will start to increase, and after that point, it keeps increasing for every 1/3-stop lower f-number. When the camera does this, it obeys the exposure triangle using brightness as a fix to match exposure, but it robs the RAWs of DR and headroom, and it meters for shutter speeds to obey that triangle for exposure, rather than give the light *capture* expected with that exposure, which would be a reasonable user option, IMO. Capture of photons is always much lower than exposure with a Bayer CFA, but from f/64 down to f/3.2 or so, the percentage is fixed, and at some point below f/3.2, the percentage drops more, the lower the f-number.

I have tested this on the last few FSI DSLRs I've owned, and it is true for them all. Supposedly, the D850 is BSI, so it should not happen on that camera if the BSI/FSI issue is real. Regardless of whether it happens with BSI too, or not, it is a real phenomenon.

Yes. The micro-lenses do not entirely compensate for the increasingly large acceptance angle as the lens aperture widens. The individual pixel wells are more like a deep shaft than they are a shallow box.

russbecker wrote in post #18767926
Yes. The micro-lenses do not entirely compensate for the increasingly large acceptance angle as the lens aperture widens. The individual pixel wells are more like a deep shaft than they are a shallow box.

I assume that this also means that DOF is therefore not as shallow as it's supposed to be based on aperture with the smallest pixels and FSI. This can interfere with "equivalence", as typically calculated based on f-number. A 7D2 at f/1.2 will have more noise and deeper DOF than a 6D at f/2, despite the functional "equivalence" which would actually be true at f/8 and f/13.

John Sheehy wrote in post #18767907
That article doesn't even mention anything about f-numbers.

There is no practical reciprocity factor with digital cameras. The amount of light flux is not the issue. It is the percentage that gets through from exposure successfully to capture in the photosites at a fixed linear rate at each f-number. That percentage varies with FSI sensors quite a bit between f/2.8 and f/1.4, with smaller pixels. Take any FSI APS-C or FF camera, and mount a manual aperture lens on it. Meter for f/2.8 in M mode, and then take a series of images with the same "exposure" predicted by the exposure triangle at all the lower f-number clicks with the corresponding shutter speed, such as f/2.8 1/500, f/2.5 1/640, f/2.2 1/800, etc, down to f/1.4 1/2000 or further, and the images will become progressively darker. With a 6D or 1Dx, with bigger pixels, you may not see the darker images until about f/2, maybe f/2.2 or 2.5 for the 30 and 26MP FF cameras. If you don't have a manual aperture lens, you can do a simpler, less elegant test by shooting an f/1.4 lens wide open in M mode, then take the same shot again, this time with the lens unscrewed just enough to lose lens communication. The latter will be significantly darker, and it will have more highlight headroom, which the firmware clipped away when proper protocol was used in the first image.

It won't show the exact optical effect, but you can see how the camera attempts to compensate for it by shooting black frames with the lens cap at all f-numbers f/3.2 and below, and at some point the blackframe noise will start to increase, and after that point, it keeps increasing for every 1/3-stop lower f-number. When the camera does this, it obeys the exposure triangle using brightness as a fix to match exposure, but it robs the RAWs of DR and headroom, and it meters for shutter speeds to obey that triangle for exposure, rather than give the light *capture* expected with that exposure, which would be a reasonable user option, IMO. Capture of photons is always much lower than exposure with a Bayer CFA, but from f/64 down to f/3.2 or so, the percentage is fixed, and at some point below f/3.2, the percentage drops more, the lower the f-number.

I have tested this on the last few FSI DSLRs I've owned, and it is true for them all. Supposedly, the D850 is BSI, so it should not happen on that camera if the BSI/FSI issue is real. Regardless of whether it happens with BSI too, or not, it is a real phenomenon.

Of course it didn't mention anything about f numbers, they don't matter.

Indeed, you only showed what I said, confirmed by the article, that this only matters under low-light conditions. You're reducing the light through high shutter speeds, or shooting "black frames". We don't use "f numbers" in microscopy, just "numerical aperture". In fact, any DSLR could be placed on a microscope (or telescope, for that matter), and the front-illuminated sensor would simply be less sensitive than the back illuminated sensor.

As f-number is nothing more than the focal length of a lens divided by the diameter of the entrance pupil, I don't see what that has to do with anything, except by adjusting the amount of light the camera sees, if the lens cap is removed.

Capn Jack wrote in post #18768290
Of course it didn't mention anything about f numbers, they don't matter.

They don't matter in a little side thread here that you seem to have developed by and for yourself. For the issue of effective QE due to angle of incidence, which was the topic before you switched it to your experience with microscopy, f-numbers are a useful proxy for a range of angles of incidence on the sensor and its microlenses.

I said nothing about light intensity making any difference to the effect I am talking about. It is about the effect on quantum EFFICIENCY. If a sensor is exposed with white light at f/8, perhaps 15% will get through the color filters and into the photosites. At f/4, still the same. At f/2.8, still the same, then at f/2.5, it may drop to 14.6%, and then to 13.9% at f/2.2, and maybe only 8% by f/1.4. All this, regardless of the absolute level of exposure. It is as if, as the aperture is opened wider, there is a virtual neutral density filter in the outer parts of it, getting darker toward the edges, because of the microlenses' interaction with the deep photosites. This not only loses efficiency, but it has an optical/geometric effect, too, as the light needed to constrict the DOF is mostly what is lost, compared to what is expected.

I clearly mentioned black frames for one reason; proof that the camera manufacturer knows about the phenomenon I am talking about and "fixes" it with RAW cooking, so images don't look dark at low f-numbers. Black frames have nothing to do with weak exposure here; they are just environments to see naked read noise, the easiest environment to detect RAW cooking. I could have just as well talked about the masked borders in actual RAW exposures, but I thought that might be more confusing to more people.

John Sheehy wrote in post #18768694
They don't matter in a little side thread here that you seem to have developed by and for yourself. For the issue of effective QE due to angle of incidence, which was the topic before you switched it to your experience with microscopy, f-numbers are a useful proxy for a range of angles of incidence on the sensor and its microlenses.

Imaging is imaging, whether through the lens of a microscope, telescope, or a camera. In microscopy, we use "numerical aperture" instead of f-stop A larger NA provides more resolution and light, but a smaller depth of field. The reference I provided didn't mention NA or f/number.

I think you are asserting there is a mis-match between the acceptance angle of the micro-lenses on the sensor and the light coming in the lens when the aperture is large (see ray diagram below)? When the aperture is wide open, more light hits at a larger angle to the sensor and the microlenses can't accept that light?

John Sheehy wrote in post #18768694
I said nothing about light intensity making any difference to the effect I am talking about. It is about the effect on quantum EFFICIENCY. If a sensor is exposed with white light at f/8, perhaps 15% will get through the color filters and into the photosites. At f/4, still the same. At f/2.8, still the same, then at f/2.5, it may drop to 14.6%, and then to 13.9% at f/2.2, and maybe only 8% by f/1.4. All this, regardless of the absolute level of exposure. It is as if, as the aperture is opened wider, there is a virtual neutral density filter in the outer parts of it, getting darker toward the edges, because of the microlenses' interaction with the deep photosites. This not only loses efficiency, but it has an optical/geometric effect, too, as the light needed to constrict the DOF is mostly what is lost, compared to what is expected.

Again, it seems that there is an assertion that the angle of some of the light from the camera lens exceeds the acceptance angle of the sensor micro-lenses? I'm pretty sure they try to build that into the design of the camera sensor although there are limits. You may be interested in this link from my employer, but another division than where I work: http://blog.teledyneda​lsa.com …le-on-optical-acceptance/
Please note they work down to f/1.2.

I note that you use the term "quantum efficiency" again, when I suspect you really mean "optical efficiency". "Quantum efficiency" is a function of the material used to make the sensor and the wavelength detected. "Optical efficiency" is the is defined by the amount of light hitting the sensor depending on the geometrical location of the sensor (photosite, or pixel, in this case) and the pixel's location with respect to the imaging optics.

I suspect that the amount of light lost (15% @f/8 to 8% @f/1.4, a change of nearly 50% loss) is probably exaggerated as a drop off of 35% with an angle of 23° angle to the pixel...see https://web.stanford.e​du …uments/2002_JOS​A-A_OE.pdf

John Sheehy wrote in post #18768694
I clearly mentioned black frames for one reason; proof that the camera manufacturer knows about the phenomenon I am talking about and "fixes" it with RAW cooking, so images don't look dark at low f-numbers. Black frames have nothing to do with weak exposure here; they are just environments to see naked read noise, the easiest environment to detect RAW cooking. I could have just as well talked about the masked borders in actual RAW exposures, but I thought that might be more confusing to more people.

The other thing one should observe if more of the light exceeds the acceptance angle for the pixels for higher f/numbers is vignetting. If they are "cooking" the numbers, you should see more "noise" at the outer sides of the image as the manufacturer compensates for light hitting those pixels at larger angles than the middle of the sensor. "Read noise" is only one aspect of what is seen- the sensor itself has thermal noise too.

Capn Jack wrote in post #18769119
Imaging is imaging, whether through the lens of a microscope, telescope, or a camera. In microscopy, we use "numerical aperture" instead of f-stop A larger NA provides more resolution and light, but a smaller depth of field. The reference I provided didn't mention NA or f/number.

Then it is not directly useful to the conversation. At least for subject distances multiples of the focal length or longer, f-ratio is a useful proxy for the angles of incidence; actual aperture size is not.

Hosted photo: posted by Capn Jack in
./showthread.php?p=187​69119&i=i220637695
forum: Canon Digital Cameras

You've said that three times now in this post. Is that to make up for your taking so many days to get what I was talking about?

I'm pretty sure they try to build that into the design of the camera sensor although there are limits. You may be interested in this link from my employer, but another division than where I work: http://blog.teledyneda​lsa.com …le-on-optical-acceptance/
Please note they work down to f/1.2.

We can directly examine the FSI digital cameras being discussed, which have easily measurable losses at low f-ratios, which anyone can test by unscrewing a wide-open f/1.2 or f/1.4 lens in all-manual mode, or by examining the black noise levels in RAWs to see how manufacturers try to sweep these losses under the carpet. This is far more relevant than optimistic theory.

There aren't enough terms, perhaps, to break down efficiency into its distinct components. I thought I wrote "effective" efficiency, at least that is what I meant. The thing is, exposure is the light heading toward the sensor plane from the lens, and QE is generally thought of as the percentage of those photons in the exposure which become charge in the photosites (most of the quoted QEs are for a green wavelength in the green-filtered pixels, which hide the actual massive losses of light, especially red light, where about 92% is typically lost to the color filters). This microlens/photosite loss occurs inside the sensor sandwich, which is why I feel that it can be referred to as a loss of efficiency, although it is not a fixed loss. It is part of the exposure/capture ratio.

In fact, I also referred to it as a geometrical/optical effect.

I suspect that the amount of light lost (15% @f/8 to 8% @f/1.4, a change of nearly 50% loss) is probably exaggerated as a drop off of 35% with an angle of 23° angle to the pixel...see https://web.stanford.e​du …uments/2002_JOS​A-A_OE.pdf

See the actual cameras that we shoot. I told you how. Please stop bringing other equipment with different design concerns into the conversation as justification for your initial denial. I mentioned a phenomenon in the digital cameras discussed in these forums, and you're trying to use special equipment to show that it is small if it even exists at all. It can be significant.

I assume you actually meant "lower f/numbers".

I've measured the phenomenon in cameras that don't correct RAWs for darker corners. Canon so far isn't cooking the RAWs in that way, at least not in my Canons. They have the same standard deviation and histogram spikes and gaps everywhere in the RAW image. The only noise differences from center to corner are those present when there is low-frequency horizontal banding noise, but that doesn't even budge standard deviations of read noise; mainly just local mean black levels.

Thermal noise is firmware-scaled just like all noises in a blackframe. The firmware can not separate them. Thermal noise is insignificant, anyway, with short exposures at room temperature, especially a DSLR in OVF mode which doesn't have a constantly-read sensor.

John Sheehy wrote in post #18769299
Then it is not directly useful to the conversation. At least for subject distances multiples of the focal length or longer, f-ratio is a useful proxy for the angles of incidence; actual aperture size is not.

Hosted photo: posted by Capn Jack in
./showthread.php?p=187​69119&i=i220637695
forum: Canon Digital Cameras

You've said that three times now in this post. Is that to make up for your taking so many days to get what I was talking about?

We can directly examine the FSI digital cameras being discussed, which have easily measurable losses at low f-ratios, which anyone can test by unscrewing a wide-open f/1.2 or f/1.4 lens in all-manual mode, or by examining the black noise levels in RAWs to see how manufacturers try to sweep these losses under the carpet. This is far more relevant than optimistic theory.

There aren't enough terms, perhaps, to break down efficiency into its distinct components. I thought I wrote "effective" efficiency, at least that is what I meant. The thing is, exposure is the light heading toward the sensor plane from the lens, and QE is generally thought of as the percentage of those photons in the exposure which become charge in the photosites (most of the quoted QEs are for a green wavelength in the green-filtered pixels, which hide the actual massive losses of light, especially red light, where about 92% is typically lost to the color filters). This microlens/photosite loss occurs inside the sensor sandwich, which is why I feel that it can be referred to as a loss of efficiency, although it is not a fixed loss. It is part of the exposure/capture ratio.

In fact, I also referred to it as a geometrical/optical effect.

See the actual cameras that we shoot. I told you how. Please stop bringing other equipment with different design concerns into the conversation as justification for your initial denial. I mentioned a phenomenon in the digital cameras discussed in these forums, and you're trying to use special equipment to show that it is small if it even exists at all. It can be significant.

I assume you actually meant "lower f/numbers".

I've measured the phenomenon in cameras that don't correct RAWs for darker corners. Canon so far isn't cooking the RAWs in that way, at least not in my Canons. They have the same standard deviation and histogram spikes and gaps everywhere in the RAW image. The only noise differences from center to corner are those present when there is low-frequency horizontal banding noise, but that doesn't even budge standard deviations of read noise; mainly just local mean black levels.

Thermal noise is firmware-scaled just like all noises in a blackframe. The firmware can not separate them. Thermal noise is insignificant, anyway, with short exposures at room temperature, especially a DSLR in OVF mode which doesn't have a constantly-read sensor.

Imaging is imaging. The math is the same, the physics is the same. The references show how the "problem" is measured and why it really isn't one for us.

Please share some references to support your statements. I have provided references and the reply is essentially "It doesn't matter because it isn't a DSLR"

Unless you have something to support there is a problem with our DSLRs, I'll let the thread go back to a discussion of the 6D Mark II

Thank you and the Pixels thank you

Just got my first full frame! The canon 6dii is my new upgrade from the canon 550D-t2i. Thanks B&H for your superb sale! I’m loveing this new camera still learning where all the buttons are. The Bluetooth connection to the iPhone is so nice to have.
I panicked when battery was charging and no battery was in the camera the viewfinder was dark and blurred. Researched and found out this is normal.
Also took me quite a while to figure out how to zoom in on live view was wondering if it was even possible. There was nothing online or in the instruction manual to tell one to use the magnifying button for this function.

Here’s two SOOC photos that I took. I will be taking family photos here on our farm in the near future.

Image hosted by forum (950120) © Momentstohold THIS IS A LOW QUALITY PREVIEW. Please log in to see the good quality stuff.

My 6D M ll arrives Wednesday!!

Needed 2 new bodies to replace 2 aging 7D M l. I got the 6D Mark l 2 months ago and was very happy with my first FF. I was torn between getting a 2nd one or the Mark ll. I chose another Mark l for $999 (the same price I paid for the 1st one). I noticed a problem with the memory card slot. It didn't "eject" the card fully. The card came out easily enough but was concerned this may be an issue down the road so intended to send it back under warranty. The next day I received an e-mail from B&H containing a special promo code to use on a few select items. One of the choices was on a 6D Mark ll package. It came with the same free items as the Mark l: an extra battery, a shoulder bag, and an extreme San Disk memory card. It also included a Canon battery grip ($200). The entire package was $1,299. With the promo code it was $1,099!! If you take into consideration that the battery grip is $200, that means I was getting the 6D Mark ll for $100 LESS than the Mark l. Could not pass it up. I had plans on getting the battery grips for both of the 6Ds as I am used to grips on all my bodies all the way back to my first Rebel.

Look forward to giving it a workout in a few weeks with the 400mm F/5.6 at an NFL game. I've already used that lens with the Mark l at a night game with decent results. The 400mm never left the house during night games because of the F/5.6 on my 7Ds, which doesn't handle high ISO well.

From what I've shot in the last week I can only say you'll love it. I had a 6d for a couple years solid camera then sold it followed the sirens call of EVF and lighter cameras ended up being a disaster not so much for IQ but years of shooting film and digital SLrs just didn't work well. You will be amazed at high ISO performance better Autofocus and you'll love that 400 at the NFL game share some pics with us.

Don't spend any time reading the technical posts preceding,,,,,it will suck all the joy out of using your new camera,,,,,,! Just go out and enjoy using it. Just got mine a few days ago,,,really enjoying it.

Enjoying my new 6dmkii. A rare catch today.