There are thoughts on the canonrumours forums that the sensor may well not be the old Bayer-type sensor but the new foveon type that they patented last year (I believe). If so this would make the photosites much larger than a Bayer 15MP sensor thus making the 18MP a more sensible thought.
The other Idea was structured around the fact that from what I understand the Foveon-type sensor is layered in triplicate, thus you have three 6MP sensors layered as opposed to one 18MP sensor. The fact that they are advertising it at 18MP may because they are trying to drag in the consumer level photographers who exist under the belief that more MegaPickles are the best thing since sliced bread.
Out of interest... do *ALL* EF-S lenses protrude so far into the body that they'll hit the mirror in an APS-H? It's quite possible that certain lenses could be disabled (ie mirror won't move) if they'd cause a problem.
mark d s wrote:
Out of interest... do *ALL* EF-S lenses protrude so far into the body that they'll hit the mirror in an APS-H?
I'm not too sure about this but IF, and that's a HUGE if, this body was to have a APS-H sized sensor with the ability to mount and utilize EF-S lenses it would be on my 'what to watch' list--not because it's EF-S compatible but because it's APS-H. Of course the camera would have to perform to standards in other departments, specifically AF performance and high ISO capability.
The important thing in resolution is the number of red-green-blue pixels sets, the pixel-set resolution. High-end digital video cameras have 3 CCDs. This enables them to capture a complete set of red-green-blue pixels for every pixel in the rated resolution. Digital cameras using the Foveon chip, such as the Sigma SD9, also capture a complete set of red-green-blue pixels for every pixel of rated resolution. So the number of red-green-blue pixel sets is equal to the megapixel rating. The megapixel rating and megapixel-set resolution are identical.
Most digital cameras and low-end digital video cameras have a single CCD to record all three color channels. This is accomplished by dividing the CCD into four pixel blocks one of which records red, two of which record green and one of which records blue. So, number of pixel sets is actually one forth of the megapixel rating given these chips. The megapixel rating is four times the megapixel-set resolution. So, you should divide the megapixel rating for these chips by four when comparing to 3 CCD or Foveon-based systems.
This explains why digital video looks so good when it is converted into 35mm motion pictures for commercial release in theaters. The digital video is shot on a 3 CCD camera. So, even though the image is only .37 megapixels, the megapixel-set resolution is also .37 megapixels. It would take a 1.5 megapixel single CCD image to produce the same megapixel-set resolution.
While Canon sold Foveon to Sigma a while back resulting in the newer Sigma models (SD14) having foveon sensors they have patented their own three layer sensor in a similar design to the foveon. Possibly resulting in the inclusion in this camera so in reality you would have a single 6MP sensor with three layers. (maybe).
Pixel Perfect wrote:
It'd be a lot better if this were a 1.3x cropper, but that's highly unlikely.
If it's a 1.3, I'd consider it. As a 1.6, I think not. I can't imagine the ISO 6400 noise being real clean with such small photosites. Could be wrong, though.
George.ML wrote:
If the sensor is other than 1.6x, why would it have an EF-S lens as kit?
Well, and this is going out on a line, perhaps Canon, similarly to Nikon, was able to build a body with a native 1.3x sensor with a 'crop' mode to utilize ef-s. Obviously this is unlikely but not completely disproved atm.
Each layer covers a different color, 1 green, 1 red and 1 blue all, in this case, 6mm each. The Sigma cameras have this. Some say it is actually a 6mm camera others stretch it and say it's 18. Some years ago Fuji had something similiar in their F700 which my wife had. I have the Sigma DP1, while it produces very good images for a P&S I credit it more due to the APS-C size sensor then the Foveon IMO.
In theory a Foveon should do excellent, I just don't think Sigma has gotten the senor fine tuned enough. Perhaps Canon would do better but we see no mention it being in the 7D in the photo of the 7D box.
M Vers wrote:
So what is it...6mp or 18mp? The difference is plenty large enough to determine--so why is there no solid proof?
Arguably it is both. It is a single sensor block of 6MP but the three sensors provide an area of 18MP.
Canon would advertise this as the higher value due to the fact that more MP is seen as a good thing by the vast majority of the consumer market.
There is no proof canon have included it in the 7D but at the same time most of this thread is supposition so I'm joining in with something which might explain the high MP on a smaller APS-C sensor.
The Sigma version is allegedly not perfect but Canon have developed their own design which may work better. Seperate patent to that held by Foveon.
If the latest rumor: "In USA: $1699 Body" is true, it's probably the end of the xxD line.
I'm upgrading from a 400D personally, before the rumours were out I was considering the 40D for the reasonable FPS and ISO performance, if this camera gives me what it may be promising I will happily spend my student loan on the body at that price. May have to get it shipped from the US to take advantage of the non Canon Europe pricing structures.
