Appreciate all the feedback, but would like even more personal experiences with the ISO/AF 'differences' between the 7D , 1dIV and speculation about the 1Dx.
With only a single weekend's experience with the 1dIV, swapping back and forth with 7D, I didn't see a DRAMATIC improvement in capture rate of the AF with 1dIV. Shooting moving targets in the 'dark', I use ZONE selection with the 7D sometimes, and overall I don't miss many shots b/c of AF. However, with all the individual points on the 1dIV, it seemed to take me longer to cycle through to where I needed them. Maybe I just needed to get more familiar with the 1dIV? but i missed the ZONE and 4 point expansion options.
To be sure, the 1Dx is bringing the AF to a new level, so that is definitely a plus there over the 1dIV.
With respect to ISO / low-level performance though, I obviously saw improvement between the 7D and 1dIV. Shooting with the 7D at max 3200 mostly, I have come to deal with the noise, but am limited in really dark gyms. I was able to shoot 4000-12,800 with 1dIV in this dark environment, but did have quite a bit of noise, most of which cleaned up in ACR pretty well. But with hundreds of shots, it does take time. What I should have done was take the same type shot with both bodies at the same ISO to compare noise but this was my first 2 body shoot and I was simply too busy focused on having 2 different lenses/options available and didn't really plan enough on a head-head comparison, my bad.
Will the 'improved' 1Dx ISO performance mean:
1). I will have less noise to clean at 2000-3200, or
2). I will be able to capture shots in the dark gyms where I currently don't get anything very usable.
3). A little of both (?)
Other features/benefits aside, how much better can we expect the 1Dx to (out)perform the 1dIV ? With my shooting style and gym limitations, I can accommodate to the FF vs 1.3 vs 1.6 reach / lens issues with my arsenal, and I am improving my positioning and shot planning at every venue, but I am wavering as to the real-world improvement in the image quality. Both will be better than my 7d, but HOW much??
1dIV ISO 6400 135 @2.2 Tv in a really dark gymPVC18Yellowreedits1D093
by PVC 2012
, on Flickr
7d ISO 3200 135 2.2 Tv in a slightly better lit gymPVC16Black7d014
by PVC 2012
, on Flickr