rjharris wrote in post #16220117
I'm just saying that if they want to sell it for $2,000.00 they almost need to get a different sensor though. If that's the case I don't see them going much more than 19 that they are and I think the focus on the 7D is fine how it is. The original 7D was right at $1,700.00 (I bought one when they first came out) and this 70D specs almost as good as or maybe even slightly better than my 7D for quite a bit less than $1,700.00.
For an example, look at the huge difference between cameras in the same line; the 5d2 vs 5d3. Based off of the MSRP at the time of their releases, there was an $800 difference. And that is with a camera that had a shorter lifespan than the 7d! Taking the 7d's longer lifespan than the average camera into account, in theory, there should be more new technology that is implemented in the 7d2 than the 5d3 (within model lineups). New technology costs money. If the 7d2 was to sell for under $2,000 then there would only be a $300 difference between the MSRPs. Which doesn't correlate with all of the other price hikes we have seen from model to model in the XD lineups.
rjharris wrote in post #16220117
It's my understanding that you can't or shouldn't put as many focus points on a crop frame sensor because the low light focusing gets worse.
I think you are misunderstanding the low light capabilities when comparing a full frame camera to a crop sensor camera. Light gathering capabilities has to do with the size and pixel pitch of the sensor. Traditionally, a full frame camera has been better at gathering photons in low light situations because it has larger pixels than a crop sensor camera (think bowl vs a cup when raining). Full frame sensors also have better quality in low light because the light isn't being split up as much as a crop sensor because there is more area for the photons to be gathered. Rather than light waves hitting the smaller pixels of a crop sensor and being split up (which degrades quality, somewhat like copying a copy).
Auto focus on the other hand, does not depend on the amount of light a sensor can gather, but the brightness of the light that the lens can gather. The brighter the light a lens and the AF sensors can read, the more information and contrast the AF sensor (different from the main camera sensor) and software has to go off of. This translates to more accurate auto focus in low light situations. AF sensitivity doesn't care whether a camera is a crop sensor or a full frame because it has already gathered and fed its information back to the AF motors in the lens before the image is recorded on the image sensor. TLDR, low light quality relates to the amount of light available, AF accuracy relates to the brightness (therefore contrast) of the light. AF accuracy is greatly dependent on the software reading the information. And AF sensitivity is unrelated to the format of the camera.
There are other factors that drive AF performance. Speed is very closely correlated with the batteries you are using. A 1Dx has an extremely powerful battery that will drive a lens' AF motor faster than a 5d III, even when the 5d III has a battery grip. Another factor that limits AF performance is the tiered camera system by Canon. They aren't going to want a 7d2 camera that can out perform their flagship 1Dx in low light, so they are going to limit what the AF sensors can achieve.
Hope this helps,