Nikon D800 official release, 36MP..

[Kayaker72]

Does anyone feel like the D800 is exactly what everyone's been asking for in the 5D Mark III?

Yep, spec wise, it sure seems like it. I've read some posts from people that are finding issue with the images Nikon has posted. Personally I think they are good, but I do find it suspecious that the highest ISO of an image they posted was ISO 640. Also, native ISO100-6400 expandable to ISO 50-25600...isn't that the spec on the 5D2? Have to be shooting in DX mode to get the 6 fps. It would be a little funny if we are watching Canon and Nikon switch roles with Canon having the DR/ISO performance and Nikon the high MP.

Overall, it looks like a great camera. The biggest thing I see, besides the MP, is the AF. Nikon set the bar pretty high for Canon. So, here is to hoping that Canon meets or exceeds the bar with the replacement to the 5DII (and 7D)....I am also happy about the price point. I doubt Canon will be much different than $3,000 to stay competitive. I am a few years off from FF (if ever), but I like to think that it would be within range if I ever did decide to make the jump.

One thing I am wondering, how did they get the FF mirror to work with DX lenses? I thought that was part of the deal, that EFS/DX lenses were positioned too close to the sensor and the mirror would hit them. I am sure I am missing something, but maybe it is just about image circle.

The other thing you've got to understand is that 99% of the time, scientific (and industrial) images look like crap.

Hmmm...I think that I must have a scientific sensor some of the time....maybe an AA filter that can turn itself on and off randomly?

[ChadS]

One thing I am wondering, how did they get the FF mirror to work with DX lenses? I thought that was part of the deal, that EFS/DX lenses were positioned too close to the sensor and the mirror would hit them. I am sure I am missing something, but maybe it is just about image circle.

I've always wondered about that myself. An EF-S lens is too close to the sensor to flip up a mirror if it's a simple hinge. However, if there's any sort of linkage in there it's quite possible that the mirror could clear. Imagine that the back/top of the mirror translated forward and the bottom/front of the mirror swung up at the same time. That would prevent smashing the close-in lens. It's an expensive (and probably loud) solution so there may be a more elegant one than that - but there are solutions.

[ChadS]

@Rocco You've got to decide: same framing or 100% crop?

Let's say you have the identically-framed portrait of a model on a 10 MP and 18 MP 1.6x sensor. They'll look mostly the same if you put it up on the computer screen.

Let's say that if you zoom in on the model's eye you could count the number of pixels that make up that part of the image. For the 10 MP sensor that might be 10,000 pixels whereas that would be 18,000 pixels. So at this level (all other things being equal) the 18 MP image would look better. However, if you zoomed the 10 MP image so that you saw 2 MP worth of pixels on the screen and zoomed the 18 MP image so that you saw 2 MP of pixels on the screen you'd actually see less of the image in the second case (it would appear to be more magnified).

Now, at this higher resolution you are approaching (or well past) the ability of a lens to resolve detail with sharpness. So you will think that the second image looks softer than the first only because you're zooming in on the softness of the lens when in fact the second exposure can have more detail (can - not will). This is all for perfect sensors. Throw in less light per pixel for the 18 MP and you get more noise - hopefully balanced by better generation amplifiers and A/Ds. Throw in the vagaries of AA filters and you've got a convoluted mess.

The only way to know if you've got a softer sensor or not is to use something like the USAF resolution chart and shoot both. If you do that with the 40D and 7D you'll almost certainly be able to resolve tigher linepairs with the 7D.

Edit: noise and pixel size and statistics...

Ideally we'll have so many photons hitting our sensors that we don't have to amplify the signal very much and we get an overwhelming signal. Grand - but not practical. As we have to amplify the signal more (read: higher ISO) more noise is introduced into the signal as a consequence of the reality of physics of amplifiers. You've also go to consider the the number of photons that reach a sensor for a particular intensity is a statistical process. Even shooting a uniform white field you're not going to get exactly 10,000 photons of the same energy level on each pixel. Some will get more some with get less. However, the more photons there are the less this variation represents as a fraction.

As our intensity drops the number of photons registered by each pixel is a lower number. The pixel-to-pixel variation is therefore a larger fraction of the overall. Now, since the number of photons that strike a pixel is proportional to the area of the pixel the pixels on a 10 MP sensor will be larger than that of an 18 MP sensor. This is also why FF cameras of the same # of pixels have less noise than APS-C sensors. I'm simplifying because there are some other things in play like quantum efficiency of the sensor, coverage fraction, etc. but the main idea holds.

What John was saying is that if you Photoshop to reduce the 18 MP image to a 10 MP image using some sort of resampling the reduced-pixel image will appear less noisy than the original - simply because the pixel-to-pixel variations will be averaged out to a certain extent.