It sounds like an excellent plan. If AF speed is not main prio, a used 5D2 and used 17-40L might be an option too. Either way will be a huge upgrade.
This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.
Smell that? It's sweet-and-sour scent of optical physics and lens design waking you from your dream...
A telephoto lens design places the 'virtual' aperture at or near the front element. So, a 300/2.8 lens is going to need at least a ~107mm diameter front element to fill that aperture with light. That front element is going to be big and heavy, and need a strong frame to support it. A smaller image circle would mean a slight reduction in some of the internal elements, but won't really make the lens smaller (or cheaper).
There's a reason we don't see EF-S telephoto lenses (except one zoom that actually starts in the normal range and has a variable aperture, meaning a different lens design) - there's just no real advantage to a smaller image circle at long focal lengths.
I'd suggest that Canon is deliberately yielding the lower-cost long glass market to third parties that are targeting the xxD and xxxD owners who may not realize the high demands upon glass that come with such high density sensors.
For the camp who predicts that the 7D2 will truly be a "mid-level" camera (meaning priced near the midpoint between a rebel and a 1DX), the expression "Future of Pro APS-C will change" means that the 7D2 will be a serious sports/wildlife Body. Such a camera could be evidence of a Canon strategy for serious/pro APS-C wildlifers to either rent or own the long L glass that meets the build quality, resolution, and weather sealing requirements of such a use case, as the reach/cost advantage is already realized in the form of the crop sensor itself.
The increased demands of the higher density sensor would be incentive enough, for those who are aware and who care, to use L glass, knowing that they are taking advantage of the best portion of the image circle as well.
If the 7D2 really targets the pro or semi-pro wildlife segment, then in my opinion Canon may assume that the 7D2 owner has a FF body as well (such as a 6D), or aspires to one, in which case there is no incentive to invest in EF-S glass at all. Moreover, accepting the wildlife specialized use case, the "single body" 7D2 owner may in fact be content with covering the WA and UWA ranges without L build quality and weather sealing, i.e. with the fine lenses available today such as the 10-22.
A 2x crop sensor would have even more reach. I think it is more important what camera sensors can deliver "sufficient" quality for the applications that most customers care about, what camera systems can deliver the right lenses at the right price etc.Yes. But Canon has shown their hand with the EOS-M, that they will stay with APS-C for a couple of generations of cameras. Why create the M-mount otherwise? It is made to optimize size for APS-C. Thats a LOT of intent going into a sensor size. The M-lenses will ALL be designed for the APS-C sensor.
It might well be that well see m43 and FF, but APS-C will disappear. After all, it is a fairly recent format and there are not _that_ many good lenses designed especially for it (but many lenses that work for both crop and FF).
A small sensor does not inherently have "more reach". A sensor of dense sensels does have more reach. Often, smaller sensors have more sensel density than large sensors, but this is no rule written in stone. The D800 seems to point towards FF sensors using the same sensel tech as APS-C sensors.