Quote Originally Posted by DavidEccleston View Post
Alright, so full-frame is nice, but are the IQ improvements I saw purely because of the full-frame sensor, or is it partially 1D specific? I know the 1D series does more work in analog before converting to digital, and it handles highlights really nicely. Would I be happy with the 5D3 or 5Ds, or do I crave some secret 1D magic, pushing me to a 1DX or something? I'm assuming the 6D won't keep up with my sports AF requirements.

So yeah, it's definitely worth considering, but if you cheap out too much, you might end up with a camera you can't always use. Try to avoid that. The 6D is newer, and has higher ISO capabilities, and can likely be found for a similar price. On the other hand, it's likely like the Rebel of the full-frame line, and has less controls. Is there a limitation of the 6D or a feature of the 5D2 pushing you to the 5D2 over the 6D?

If I get to the point where I am seriously considering the full-frame upgrade, I'd probably rent each body on successive weekends, and compare the results vs. price differences to try and answer the "Do the magic 1D secret sauce exist?" question. That may not make as much sense in your price-range, where the rentals costs would be a fair chunk of the body price, but that's my thought process about the upgrade...
Disclaimer: my experience with 6D is limited to a single four-day rental because one of our 7D bodies was in for repair. I shot two charity walks with it, something we enjoy doing but absolute image quality is simply not a factor (getting the images culled/cropped/delivered fairly fast is). I didn't notice any secret sauce with that camera. I'd rented a 5D prior for a charity event, but wasn't experienced enough to really look for the sauce.

OMG, yes, there's some sort of secret sauce in FF. I feel like almost every EF (as in "every Canon lens that's not an EF-S") lens just makes more sense on FF, and the images are just more WOW across the board. This goes for 5D3, 5DsR, and 1Dx, having owned 40D, 7D, 1D3, and now 5D3, 5DsR, and 1Dx, while also having rented 5D, 5D2, 6D, and 7D2.

Amongst other things, years ago I had a nifty fifty. I used it on my 1D3, and once I finally went back to TDP's review and realized that it was best if I stopped down to f/2.8, I discovered that it was a decent lens, but felt the focal length just wasn't all that amazing (and with a 16-35/2.8, 70-200/2.8IS, and later a 24-70/2.8, it didn't serve a purpose, and got sold). Now that I've gone FF, I've picked up the 50/1.2 and wowsers. Sure, I can shoot with that lens for a while and just crank out magic all day long. I had a blast at a baby shower shooting the kiddos playing with bubbles and such.