Originally posted by CindyV I am a fine art photographer and I use my camera as an artist uses a brush.
So, just disable the whole AF and focus manually, makes more sense to learn to focus than trying to learn how to circumvent the AF system. After re-reading your first post, it would make your life so... oh so much easier to just switch the camera to MF and be freely creative. Which is re-enforced bu this:
Originally posted by CindyV I just want a camera that will do what I want it to
And then there is this
Originally posted by CindyV I exhibit in galleries and I need to be able to enlarge my photos beyond 16x24.
T3i has enough resolution for good 16x24. If you wanted better, clearer and sharper pictures, a better lens would have made more sense than a new DSLR with a consumer grade super zoom. More megapixels will only allow you to crop more. There are lots of great photographers still using 6mp cameras (check the Pentax Pro gallery for example)
Originally posted by CindyV I see that Nikon is coming out with a new 18-300
Which will be of pretty much equal IQ as the Tamron/Sigma/Pentax/Sony/... Paired with a body which will be of similar IQ as the other guys. You will never win if you are thinking this way. A Nikon sticker doesn't mean you'll have a Pro quality, better than everything else lens... They too make crappy lenses
One last thing. I cannot wrap my head around is that even though Canon is Canon and Pentax is Pentax, they're both DSLR of very similar design. They don't work differently, ergonomics are slightly different but when it comes down to taking pictures, they're similar. I had a Sony, a few Pentax, a Panasonic, shot and still shoot film... Girlfriend has a T4i and a Sony... and besides button location and the way settings are changed, I can switch cameras all day without changing how I shoot. All DSLR works the same way and honestly, there isn't all that much that is different between brands when you stay within the same price range.
It's not like Pentax are doing thing differently. You found out that the K-3 has a terrible, unacceptable and so sub-par auto-focus system that it is amazing that Pentax are still in business (according to youtube). Anyone who shoots Pentax will agree that Canikon/Sony are faster in some cases regarding AF but Pentax is far from being sub-par, especially the K-3. I just got a K7 yesterday and even if it's 3 generations behind the K-3 the AF is more than adequate for day-to-day shooting. Paired with a similar lens (50mm) I can't say that the T4i is all that much better. T4i will give me many more "in focus" pictures when snapping photos of my dog running than the K7 or the K5 but more often than not, AF will lock on the wrong part of the dog, or or the grass or trees in the back... more shots in focus but not more keepers...
Your last photo is very puzzling to me. Shooting a moving subject, handheld at 1/13, at 300mm even with VC is quite a challenge. I attribute the very little water which is in focus to plain luck, not camera AF or lens or whatever. Also I'm very intrigued by the fact that there is indeed something in focus... At 1/13 you shouldn't have anything sharp, not with moving water, you should get motion blur. (even more so since the "rock" in the top left is blurred more than what the DoF would do)
When I learnt photography, a basic rule of thumb that was given to me was that if I wanted to capture "frozen" motion, I needed three or four digits (1/500 or 1/1000) ... (Another one was when you get down to two digits (1/60), hold your breath, steady yourself and relax, and in the single digits (1/8), get a tripod)