Hunger for quick focus

[Glenn NK]

1) I've recommended AI Servo three times in this thread, and Trev (Splatsworth) attests to its value.

2) The back button focus method was discussed at great length on POTN about four years ago, and the consensus was that it was useful. http://photography-on-the.net/forum/...0D+star+button

3) Live View focusing is known to be problematic (well pointed out by Richard).

4) The Tamron 17-50 lens has been tested and the focus found to be "so-so" for speed (Photozone reviews).

5) The 550D (T2i) is quite capable up to ISO 800 which would certainly help in eliminating camera shake - but with the IS lens and shutter speeds of 1/100th second, this doesn't appear to be the problem. Not incidentally, the one image taken at 1/30th second has some areas that are quite sharp - this should rule out camera shake.

There seems to be enough for the OP now to solve his problems.

Glenn

[Doctor Andrei]

One final posting on this subject and then I will let the thread die unless we hear from Dr. Andrei

http://www.ephotozine.com/article/ca...r-review-12948

"During LiveView, two focusing options are available – Contrast Detection and Quick-mode. The contrast detection is improved over previous Canon models, taking around a second to lock onto a static subject in good light. In poor light the system struggles and can take four of five seconds to lock on, if it manages to do so at all. The Quick-mode option is certainly quicker and more reliable, but the screen is blank while the camera attains focus, which is not ideal, especially if your subject is in motion."

Tried quickmode several times and i just dont get how it works. As i try to focus the screen goes blank and the shutter sounds though I m not pressing fully, but theres no picture left in the memory.
To Glenn: AI Servo and upping ISO really work, but as i saidvpreviously just switching from tamron to canon lens doubled up the speed of focusing. Using the back button didnt work for me, ive read the manual and did as it s told there but nothing happened. And ive always relied too much on auto modes. Thanx everyone for ckearing it all up for me.

[Glenn NK]

Another useful link on focus using the back buttons:

http://www.learn.usa.canon.com/resou..._article.shtml

[Black Pearl]

So you are using the rear screen to shoot pictures?

I'll take it that you are - then you're using the camera the wrong way and that is why you're having focus problems. A DSLR like yours will AF in Live View but it is a massive compromise and something that should only be used if you want to shoot from an odd angle when the viewfinder will be difficult to look through or when shooting video. Try using the camera correctly by composing your shots through the optical viewfinder and you will find that the focus is near instantaneous and your keeper rate will go through the roof. I know you said the Canon lens was faster than the Tamron but believe me the difference between Live View and the proper viewfinder is massive.
If you had wanted a camera where you can use the rear screen then you would have been better off buying a Mirrorless System Camera like a Panasonic G3 which are designed to focus using their LCD screens. If this is the case then you might just have to bite the bullet and change systems.