CCD vs CMOS: better color and more film like look (PROOF)

Started Jul 15, 2014 | Discussions thread
fPrime Veteran Member • Posts: 3,573
Re: Circular reasoning

Eric Fossum wrote:

fPrime wrote:

Sara Valentine wrote:

fPrime wrote:

Sara Valentine wrote:

robert1955 wrote:

fPrime wrote:

Eric Fossum wrote:

"There is a dichotomy between DR at base ISO and High ISO due to the differences in conversion gain required between a large pixel, high full-well-capacity (FWC) sensor like the D3x/1DX/Df vs higher density sensors like the Sony 24MP/36MP Exmors. In a large pixel sensor, the FWC is much higher, resulting in a higher amount of referred read noise, which translates to lower base ISO DR, but this disadvantage turns into an advantage at Higher ISOs due to both the higher conversion gain of the sensor and also the lower total read noise aggregate from fewer sensels that must be read. The opposite appears to be the case in smaller pixel sensors, as they have shallower FWC but also benefit from Sony's Exmor Column-Parallel A/D conversion technology."


I remember contributing a number of comments to the referenced thread, as did many of us. I hope you went back and read them all. Sony's marketing BS still smells the same, years later. (I know you just copied and pasted, but that could be a considered a secondary sin.)

Ah, but the above wasn’t Sony’s marketing spin. That was entirely Horshack’s interpretation of what he observed in actual testing.

Actually his first words in that post were: The A7s will be released in about two weeks

The thread lasted two days, I don't think actual testing was involved

This isn’t the first time someone else’s writing was selectively cut and pasted in order to contort them to fPrime’s agenda.

Nor is it the first time Sara Valentine misread the context of a discussion before opening her mouth only to embarrass herself in the process.

To wit... here the relevant comment to this discussion on small pixels and high DR by Horshack is bolded and relate solely to his extensive prior testing of the D8xx series employing Sony’s Exmor sensors.

What was clipped (but still referenced by me via the provided link) were his introductory comments about the potential of the Sony A7s. Why? Because these conjectures are irrelevant to this discussion, a little detail that somehow escaped both you and robert1955.

Again... the question posed in this thread is do small pixels move inverse to larger dynamic range and not if the Sony A7s or Sony’s marketing for it measure up. Nothing here was contorted with perhaps the exception of your poor interpretation of the facts, lol.

It will be day of mild celebration the day you bring facts to a discussion.

Pop the champagne. I bring facts all the time, just ones that you and your cohorts find to be "inconvenient" to dispel.

I've posted more data/evidence on this specific forum within the last month than you've posted on all combined forums since you've been a member on DPR. Don't make me laugh!


I have to say this is one of the dumbest forum discussions I have witnessed this year. Just look up a historical CFA spectral response curve from either a paper on the IISS website or perhaps SPIE or IEEE, and compare it to a modern curve. Is the transmission in the passband higher or lower, and is the width of the passband wider or narrower, and is out of band reject stronger or weaker? And no, I am not going to do it for you, and yes, it might take 10 or 20 minutes to get what you need.

That's been done already and rather conclusively tied to worse color results. Here we see again the weaker CFA of the Canon 5D Mk II versus the Canon 5D.

And here The_Suede describes the color effects:

The 5D2 is both more AND less like the human eye when you look at it from a more controlled, dispassionate PoV.

The difference between them is that in the generations starting with 50D Canon has changed the classic "R,G,B" type of Bayer colour filters into "orange, warm green, blue". This is, if you do it well, and control your filter parameters well a very good thing for most intents and purposes.

A few things makes the solution less-than-optimal though. When you design a colour filter set, you only have a fixed amount of materials to work with. The materials you use MUST be able to function in the process that physically makes the filters (we're talking about depositing +/-2% amount material onto a very well defined square about 5x5µm large here...) and it has to be non-fade, non-sensitive to certain material used in the sensor surface and so on.

So, to get as close to target as they can, Canon has used a mix of material that sometimes puts the camera into trouble. Especially the "double-hump" in the orange channel in contemporary models can wreak havoc with colour accuracy in the range red>green.

But one does have to separate "accurate colour" from "pleasing colour". Even though the 5D2 and the likes of it have some very real problems (very red orange, and purples are very hard to get right - even in perfect light) it also has some positive effects.

When the light goes crazy (very low K temperatures, fluorescent lights and so on) the 5D2 keeps on top of trying to get skin-tone "about the right mid-orange", and "about mid-high saturation". This is not in any way "accurate", but it's easy to work with.

In good, balanced light spectras (daylight, studio flash) the 5D classic is miles ahead in colour definition and hue accuracy though. You get a much higher "hue-resolution" than with a 5D2. In landscaping, this might be seen as a lot higher colour definition - two trees standing next to each other have a different green colour base. Parts of foliage are more saturated with either phycocyanin, carotene, or xanthophyll chlorofyll base mixes, making them all slightly DIFFERENT green compared to the foliage parts right next to it. Some cameras can differentiate between those (very similar) colours, some just can't.

So what the 5D2 gives you is "average skintone", almost no matter what the circumstances are. This might be seen as good or bad depending on what you prefer. It also introduces some other very serious problems - like the magenta/green chroma noise caused by the unusually large amount of saturation amplification needed to make the raw file red>green range look like real colours. This is a very real "Canon problem", and the colour filter choices they've made is what causes it.

I must be a little dumb because I cannot figure what your real question is except you have the basic feeling that color quality has changed over the years. Probably true, but scientifically, color fidelity has generally improved, even if visually it looks different from film or even image sensors of years past.

So I guess all the CCD proponents who signed an open letter to Leica requesting the M10 be quipped with a full frame CDD sensor are dumb?  And The_Suede who argues passionately that the worse color discrimination  of the Canon 5D Mk II must be dumb? And for tying all this evidence together and associating it to the downward trend in SMI scores, I must be dumb?  That's a lot of people to write off, IMHO.

On the other hand, if your goal is to troll and insult, then nevermind. I cannot be sure.

And where have I insulted anyone here?  Level that charge against Sara Valentine who quite clearly was shown to have grossly misrepresented what I've contributed or to Tony Beach who can contribute nothing but ad hominem attacks.

If you ask me, Eric, your skepticism about the decline in color fidelity might be biasing your sense of fairness.


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