[/quote]QuoteFirst, you put too much weight on DXO's numbers. As far as their sensor tests go, they do not actually measure "sharpness" or anything like that. It's actually extremely difficult to objectively test a sensor in terms of sharpness, as you have to use a lens to do so, in which case your not testing a sensor, your testing a sensor and lens combined, which totally changes the outcome (and the reasons why you get that outcome). The other problem with lens+sensor tests is they are bound by the least capable component...if the lens is the weak point, then no matter how good the sensor is, your output resolution is limited by what the lens is capable of...you can never resolve more than the lens resolves, period. Similarly, if the sensor has limited resolution and the lens is a powerhouse (like the Zeiss Otus 55mm f/1.4), then your output resolution is limited by the sensor...you can never resolve more than the sensor resolves, period. That makes determining how sharp a sensor is a very muddy issue, one that cannot be definitively pinned down. Hence the reason DXO measures things like SNR and dynamic range and color sensitivity in it's sensor tests...that's all they CAN measure.
This is not news. Lets leave DxO out. I am sorry I even mentioned them for this discussion. I mixed some info and used them as a point of reference. Its something that can happen with the amount of info I go through. Please accept my blunder as a simple error as DXO is often the reference point for sensor quality, and I understand it is not of sharpness of the sensor, and more with DR and ISo, and the related.
It's not a problem to use sources like DXO as a point of reference. It just helps to have all your facts strait before doing so, so you don't mislead or confuse or otherwise sidetrack readers with incorrect or inconsequential information. ;P
QuoteRegardless of what DXO has to say about the D800 or D800E sensors, the removal of an AA filter does not increase image quality. Actually, in all too many cases (quite possibly the majority of cases), removal of the AA filter is guaranteed to REDUCE image quality, thanks to increased aliasing in general, moire specifically. This is clearly evident by all the numerous standardized image tests done with cameras over the years...while sharpness has increased in some newer cameras by a small amount, so too has moire. DPReview has plenty of examples where the removal of AA filters in Nikon cameras, or even just the weakening of the AA filter in many brands (including Canon) has greatly increased the amount of moire that occurs. (A great baseline for comparison on DPR is the 7D...it has an appropriately strong AA filter and doesn't suffer from moire at all. You can compare any newer camera with a sensor that is supposedly "better" than the 7D because of the removal or weakening of the AA filter...those images will be sharper, but they are usually riddled with moire.)Quotewhile sharpness has increased in some newer cameras by a small amount, so too has moire
The moire is subjective. I'm not too interested in the DPReview samples showing loads of moire issues. I have plenty personal samples I can stand by to tell you otherwise. Many samples in those cases are looking to show moire, and samples of it.
Actually, moire is a concrete, immutable artifact of repeatable patterns near nyquist interfering with the sensor grid. It not only leaves behind funky color and monochrome patterns...they are neigh impossible to correct in post...there IS no full moire removal in any RAW editor for a very good reason: It's impossible. You can reduce color moire, however depending on the tool, you might end up with color desaturation, blurring, etc. as a result. Even after removing color moire, the underlying monochrome moire pattern remains, and it cannot be removed (at least, not without significant blurring.)
We aren't talking about a subjective factor if IQ here, we are talking about a detrimental, and permanent, factor of IQ that gets introduced when the AA filter is removed. The DPReview sample images are not intentionally trying to show moire...they are simple sample shots of their standardized test scene. Moire occurs in their samples as a CONSEQUENCE of weak or missing AA filters. You can't simply brush moire and aliasing to the side and call it a non-issue...it is a critical issue to a great many photographers.
Quoteremoval of the AA filter is guaranteed to REDUCE image quality
Be more specific. As with this statement, in this discussion you are saying that fullframe or larger sensors that are not using AA have lower image quality. How do you figure?
I explained it in the text you failed to quite.
QuoteIf the things you photograph have no regular/repeating patterns, and do not contain any elements with clearly defined edges, then increased aliasing due to having no AA filter is not an issue. There are not very many forms of photography where that actually turns out to be the case...landscape photography is probably one of the very few. Even say insect macro photography, for example, will suffer from the removal of the AA filter...things like antenna, feelers, legs, wing veins, anything thin, strait, with high contrast to it's surroundings will end up with clearly aliased edges, and not even a highly optimized AHD demosaicing algorithm will be able to hide that fact.
The underlined falls under EXACTLY what I shoot on a regular basis, and I, with all the respect I have for your knowledge as I have read much of your posts, I think you are simply flat wrong about this. I have worked with about 20 digital camera systems in the past 24 years. I certainly don't have the understanding of sensors, and electro engineering you do, or even in the realm of it. I know I have shot just about everything there is to shoot, and I specialize in macro work WITH dealing of " thin, strait, with high contrast to it's surroundings ". I uesd the Kodak 14mpixel SLRc camera, and if it didn't have issues with handling light, I would continue using it. The images from that didn't suffer the things you claim. Nor do the MF backs, tossing the optional AA filter aside. (never used one to this day). Has moire EVER happened? Yes. Can I remember it being a problem or can I even count on my 10 fingers vs over 400K frames (with half using filter free cameras)? NO.
It's fine to have personal preferences. To base the entire discussion of "Canon EOS sensors and technology" solely on your personal preferences kind of makes it difficult to have a coherent discussion. Your personal preferences should really be left out of an objective discussion of the fundamental technology behind sensors, otherwise were just in the muddy territory of subjective muck, and anyone can make any argument to justify their own personal opinions. I personally try to remain objective when discussing technology, and leave my own personal preferences out of the discussion.
Regarding whether moire is a problem on MF cameras, Leicas, etc. If you do a few quick web searches, you'll find that they are a huge problem. There are countless threads on the subject, dating back many years, with MF and Leica users (and increasingly Nikon users) complaining about how bad the moire and aliasing can be on their incredibly expensive cameras. The solution, for many, is to use the lens so act as the AA filter. Either stopping down beyond the diffraction limited aperture of the sensor, or slightly defocusing, etc. One way or another, people have to deal with moire and aliasing if it occurs. If you have to constantly perform a very slight defocus, that makes using an autofocusing system very tedious. Concurrently, having to stop down more than you really want to in order to force diffraction blurring to soften the image is also less than idea.
You say you have used a lot of cameras over a lot of years. I'd be willing to bet many of them were film cameras, in which case moire was never a problem thanks to the random distribution of grains. When it comes to digital cameras, until recently, lenses, while good, were never as good and sharp as they are today (at least, in the DSLR world...for MF, most lenses have always been rather exceptional.) The softer lenses of the past helped to deal with the problem of missing or weak AA filters. Today, we have a convergence of several things that can only lead to significant problems with moire and aliasing: Radical improvements in lens quality, pushing their maximum resolving power to new limits; sensor resolution increasing at a slower pace than lens resolution; removal of AA filters. This is kind of a perfect storm...some manufacturers are apparently doing everything in their power to make moire a very serious problem for a lot of DSLR photographers, which will ultimately put them in the same boat as Leica and MFD owners: Having to defocus or stop down to force blurring and use the lens as an artificial AA filter.
Did you discuss the bold area I highlighted above (about the ratio between lens to sensor) a bit more in detail someplace? This is likely the feature I'm looking for to be optimal, and likey what the D800E, and A7R have factored in. It is my next criteria for my future camera/sensor purchase.
If you mean the fact that output resolution is based on the convolution of lens+sensor, I've discussed it so many times all over this forum, it shouldn't be hard to find a topic with all the details. The detail in an image (raw file) is the result of a complex convolution of real-world details. In mathematical terms, assuming gaussian-like blurring behavior (which is reasonable), output resolution is roughly equal to the root mean square (RMS) of the input resolutions. Well, to be more specific, the size of the blur kernel that represents the output image is approximated by the RMS of the blur circles of the lens and sensor.
So, if your lens blurs by 3µm and your sensor has 5µm pixels (the lens resolves more detail than the sensor), then the output blur is SQRT(3µm^2+5µm^2), or 5.83µm. Notice that the output resolution is lower than BOTH your sensor and lens. If you improve your lens resolution as far as possible, let's say 0.7µm blur circle (the wavelenght of red light), your output blur is 5.04µm. Your maximum resolution is limited by the sensor...no matter how good your lens is, you can never resolve more detail than the sensor is capable of. This goes the other way as well. Let's say your lens blur is 3µm and your sensor has 2µm pixels. Your output blur is 3.6µm. If you reduce your sensor pixels to 800nm (0.8µm), your output blur is 3.1µm. You can never get any better resolution than your worst performing component.
That's why I always say the whole notion of sensors or lenses "outresolving" the other is more myth than fact. In one sense, I understand why people think about it that way. In reality, the two work together to resolve your image...without both, you have no image, so there really isn't one outresolving the other. The real fact of the matter is your output resolution is never as good as the potentials of your lens or sensor, and your output resolution can never be higher than the least capable of the two. Further, lenses have non-linear performance...as you stop the aperture down, their performance drops. It's tough to say a lens outresolves a sensor in general...at what aperture does it "outresolve"? And by how much? Enough to matter? Or is the lens just outresolving by a tiny bit? When you stop down to f/8, is the sensor outresolving? These questions really don't matter...the thing that really matters is how the output image looks, and regardless of which thing you change, more resolution is pretty much always a good thing, sometimes a neutral thing, but never a bad thing.
The D800/E sensor is definitely higher resolution than the 5D III, for example...however Canon lenses outperform most Nikon lenses, so in most cases, the better Canon lenses paired with the lower resolution 5D III outperform, by a small margin, the D800/E. Even DXO's own lens data shows that. The D800 sensor will certainly make the absolute most out of Nikon lenses, but until Nikon improves their lens designs, the D800 does not actually perform better, in the real world, than the 5D III. Ironically, it is thanks to that very fact that moire with the D800E is not a bigger problem than it is...the lenses soften detail enough that moire tends to occur minimally. The day Nikon lenses perform as well as Canon lenses, however, keep your eyes and ears peeled: The wrath of the moire-hating D800E user will be heard around the world. ;P