AlexTokyo wrote:
Kevin, thx for the info about the AF sensor. I need to restate my question:
I assume there is a NEED for more accurate AF when you use bigger MP. A subject slightly out of focus might be OK for a given print size, but when cropped (and printed at the same size) could become unacceptable.
In effect, cropping just reduces the circle of confusion. So here I am again w/ my silly question: does anybody know if Canon adjusts the AF accuracy as it cranks up MP?
This could be real good news for the ones (like me) who hope for better AF...Show more →
In my experience, the denser the pixels, the higher precision the focussing system needs to be (otherwise the higher potential sharpness is lost). Canon needs to develop a more accurate system. I don't know if the EOS mount is capable of providing the accuracy needed to reliably make use of 24 full frame megapixels and above.
It's from all the pages containing "7D" that point to the canon teaser. "7D" doesn't appear on Canon's site......but since everyone linking to it list 7D, google figures it's relevant.
digitalbug30d wrote:
looks like the new body is a 7d...put 7d into google and this pops up
EVOLUTION
www.canon.com/moon/en/ - 2k - Cached - Similar pages
That because a lot of sites has the phrase 7D linked to that site, that's all. Thats how google works.
brainiac wrote:
Just have to keep squashing this myth. By your reasoning you should go back to using a 3 megapixel camera. Your reasoning is wrong. There is no high iso penalty for higher pixel density now. There is nothing crazy about a 24 megapixel sensor as (a) it will be no worse at ISO 25600 than a 12 megapixel version of the same technology, and (b) the new 12 and 6 megapixel sRaw modes will mean that you can choose resolution appropriate to the work you are doing.
Nikon folks will keep perpetuating these myths... until their D300 is upgraded to 16 MP. Then, all of a sudden, these noise myths will disappear altogether. Wasn't that the same with the 5D when it was first released... that FF is redundant, that APS-C is the BEST format out there... until the D3 was released.
Canon folks, on the other hand, always claim they want fewer pixels until Nikon releases something with higher pixel count... then they'll start b***hing about how far behind Canon is when compared to the competition.
brainiac wrote:
Just have to keep squashing this myth. By your reasoning you should go back to using a 3 megapixel camera. Your reasoning is wrong. There is no high iso penalty for higher pixel density now. There is nothing crazy about a 24 megapixel sensor as (a) it will be no worse at ISO 25600 than a 12 megapixel version of the same technology
Brainaic, That is absolutely not true, and someone with your extensive experience & general knowledge should know better. Photosite size has a significant effect on noise levels and dynamic range. -almost by definition. This information is easy to find online. Photosite technology is no doubt better now than 3 years ago, but you specifically wrote "of the same technology."
Ralph Conway wrote:
Ah! thanx. That was as far I remember why I asked for a split image screen. O kay. I understand its horrible to focus manually. But that is a chance, a camera gives you. Nice, to be able to use it. When my 30D does not get into focus like i want it, I switch to MF. I would never buy a camera that does not offer MF. Its one of the most important important feature. More important than any weather sealing, horizont line stuff, etc.. Thats it. I do the picture. If a viewfinder does not give me the chance (my 350D did not) its not a camera. I am a photographer. I do the picture. If the camera does not find the focus, I have to tell it, where it is. A 12800 pic is extreme! So if AF does not get it and I want to shoot, I do not ask for "pro" AF, I just switch to MF. ...Show more →
For me, 9 point AF would be enough if the AF points cover a large enough area. However I would want them all to be the cross-line type, so that if I select an AF point in the corner, I'll still get the same quality AF as in the center.
Cableaddict wrote:
Brainaic, That is absolutely not true, and someone with your extensive experience & general knowledge should know better. Photosite size has a significant effect on noise levels and dynamic range. -almost by definition. This information is easy to find online. Photosite technology is no doubt better now than 3 years ago, but you specifically wrote "of the same technology."
I think the resolution here (sorry for the pun but I can’t resist) is to think of noise for a given square area of the picture in printed or in screen form, not per pixel. Once you get to gapless micro lenses, the sensor is capturing all the light anyway. While on a 24mp sensor the individual pixels will be noisier at a given low light level than a larger 12mp pixel on the same sensor size (which is getting twice as much light. However for a image at th same size, the visible noise per unit area will be basically the same. This shows in prints form the 1Ds III which are very good noise characteristics, even when quite noisy at a pixel level. Printed at the same size several pixels are averaged, smoothing away the noise. Canon's new sRaw technology will average away the noise from a 24mp sensor to a 12mp image giving the equivalent (broadly) of the same sensor with larger photo sites.
So a 48Mp gapless micro lens sensor would (of course be even nosier at a per pixel level, but have the same level of noise per unit area. as a 24 and 12mp sensor using the same CMOS, DIGIC and A/D technology.
So, from a simplified perspective, yes for a given sensor size and CMOS, DIGC and A/D technology, pixel size is close to irrelevant for high ISO noise on prints. There are some minor details that actually favour the higher pixel count sensors up to a certain point. For example the impact of a 'hot pixel' is smaller and can be more easily averaged out at a high pixel count, but then you get more of them per image... Equally with the blurring of most images on high resolution sensors (especially anything outside the critical focus, having multiple sensors per area getting the same colour values allows easier noise averaging without loss of details. And the old circle of diffraction comes in limiting resolution.. Apparently somewhere around 65mp on a FF it doesn’t make much sense ot have more pixels as they will each generally be resolving too much for a lens at F2 or smaller apertures.
I'm sure the more technical will pick holes in my wording.. However I am confident that the principle is the basis of Canons current and next 3-4 years sensor strategy. You can see the evidence in the 50D high ISO pics now emerging. And I’m sure he images from the 5D II will prove the point even more, with ISO 25600 looking like 12800 on the 50D, which looks like 6400 on the 40D.
I must admit that all the tech stuff I read did not relate to gapless micro lens sensors.
Perhaps Brainiac is correct after all, though only for the very newest sensors, and if so I apologize!
-But I want to read more about this before I fully commit to the idea. I get the basic idea though- If there are no gaps (are these photosites square?) then there's no accumulated area loss.
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-note, though, that it is still wrong to call the other poster's info "a myth," since it is correct regarding all older sensors..
Cableaddict wrote:
Brainaic, That is absolutely not true, and someone with your extensive experience & general knowledge should know better. Photosite size has a significant effect on noise levels and dynamic range. -almost by definition. This information is easy to find online. Photosite technology is no doubt better now than 3 years ago, but you specifically wrote "of the same technology."
The 7 MP Canon G7 has smaller pixels but better performance (high ISO as well as dynamic range) than the 4 MP G3 and 5 MP G5. The 10 MP Nikon D80 has smaller pixels than the 6 MP D70 but improves on its performance. With the swtich to CMOS sensors, the 12 MP D90 is even more promising.
digitalbug30d wrote:
id think they would have 5d,5dmk2,3d linked as well makes lil sense since everyones saying 5dmk2 not 7d hence the title of this thread
they do to an extent both 7D and 5D MkII work since those are what people have linked the most i guess
