Hi all, sorry for just another 'what should I buy' post but I'm really wanting to get it right this time.After recently upgradingfrom a 40d to the5d MkII I found the AF performance wanting when shooting fast moving subjects. I then got a 7d to correct that but may consider replacing the 5d/II with one of the above bodies. I'm niether wealthy nor particularilyskilled, but this is our main hobby and I'd really like (not need) to keep two bodies. Now the obvious answer is that with the two cameras I have I've got the best of both worlds. Undeniably standing pat is an option I'm also considering vs. upgrading the 5D/II to one of the 1D bodies.


As I see it (ccorrect me if I'm wrong) the MkIV has a faster shutter (10 vs 5) but after that I can't see much in the Mk IV specs to make me go that route. $5k for the 1D Mk IV (when available)orI can get a refurbished 1Ds Mk III for $4.5k. Assuming I can live with the slower shutter speed (continuous shooting) and smaller number of consecutive shots,are there other reasonsI should consider the newer Mk IV? I've got reach with lenses/1.4x TCso the true full frame appeals to me vs the 1.3x crop sensor of the Mk IV. I also understand that the 5 extra MP's of the Mk IIIare not in and of itself that big of a deal but it can't hurt as I do end up cropping often. Probably waiting until Bryan's full review of the MkIV is in order as well.


My shooting is sports,energetic dogs,landscapes, and I also like various wildlife shots. Getting birds in flight with the 5d/II wasn't going as well as I had hoped it would. Nor a fast moving dog or motorcycle, especially when closing on me. That's probably the crux of my question right there - is the AF speed and precision of the 1Ds Mk III up to the standards of the 1D MkIV? I realize I'm asking for a simple answer to a compicated question. Either one should be significantly 'faster' than my 5d/II, as the 7D has proven to be.


In any event, I genuinely appreciate anyone's input. gary