T2i Focus

when i first got the T2i and focus on a subject there was lights inside my viewfinder ...some green and some red....now i only have one Red Light that comes on the lower right.....i was wondering what i may have done..
thanks in advance.....i know Rookie... lol

You probably have enabled single point focus, which can be a good thing assuming you are aware of which point is being used and how to change among the nine available on the T2i (I think 9). Go to http://www.digital-photography-school.com …p-single-point-af-methods or get the manual out. See page 17, the top right button on the camera back and then go to pages 68, 158 and 183.

thanks sooo much John...heres a photo i took a few minutes ago...the red light was on the birds wing...i was shooting Auto...with my EF-S 55-250mm...at 250mm,,,only photo shopping done was to crop it 100%

Richard, several things might help, although you might be near the best this combination can do at the 100% crop level.

First of all I see by the limited EXIF data that you were shooting at 1/400 sec and f/6.3, the ISO being 640. I'm going to make the assumption that the lens had IS and you had it on so I think the first thing to try would be to move the ISO to about 1600. That will enable you to get your shutter speed up to 1/1000 and camera motion will be far less of a factor. Try to get a combination that maintains the aperture at f/6.3 minimum, perhaps f/8 as long as that shutter speed is up.

Next thing, the focus point works on points of significantly differing contrast. The fact that you had a red light indicates focus was acquired but there isn't huge amounts of contrast in the red area of the tail. Also, there is some basis to use the center focus point, lock on that and then recompose, although that should not be much of an issue on a telephoto zoom. If you get another opportunity focus on the area of the feet where they meet the edge of the feeder. There is a bit more contrast there so maybe the lens can lock in an improved focus. The balance of the bird should be well within a good depth of field and totally be in focus. At f/5.6, 250mm and assuming a subject distance of about 5 meters (roughly 16 feet) the depth of field is 0.085 meter or 3.3 inches. As you can see if you focus on the feet, 3.3 inches will catch the whole bird except for the tip of the tail. If you can get the aperture up to f/8, again at 5 meters subject distance and 250mm, then your depth of field goes to 0.122 meter or 4.8 inches. Even better!

Go here for a good depth of field calculator...http://www.cambridgein​colour.com/tutorials/d​epth-of-field.htm. Scroll down for the calculator; in the camera type box select "digital SLR with CF of 1.6X" for the T2i. The 1.6 CF means that the effective field of view is 1.6 that anticipated by the same focal length on a full frame camera. In your case, the 250mm you used is effectively the field of view of a 400mm lens on a full frame body or what we would have seen in the old days with a 400mm lens on 35mm film type cameras.

thanks again John...i will sure try those settings.....during the Winter all i basically do is watch the bird feeder....unless it snows then i go out into the mountains and look things of interest....thanks again...i really appreciate you talking time out to help me...when i get another opportunity i will do as you suggested and post the photos here for you to see and help me like on this photo....i noticed the tail was out of focus too but didnt know what to do to correct it next time.....