a question about focus

I seem to take a lot of shots and get a few in great focus...is this the norm or am I that pathetic?

I adjust my focus from one shot etc. depending on the situation, I use auto focus mosly becasue I shoot my kid who is a moving target and I am just not familiar or comforable with manual yet. Also my nifty fifty is a pain with that tiny ring that is hard to get at. I try to use the fastest shutter speeds and such...I dunno

What mode do you shoot in? Try using Tv at, say 1/250 or so and set the AF mode to AI Servo. That way the camera will keep tracking as long as you've got the shutter partially depressed. If you're using Ai Focus, it takes the AF system a bit to realize that the subject's moving, so it lags behind.

What aperture are you using? Doesn't take much movement to throw it out of focus with a large setting on that lens. Stop it down a little.
I know with active kids you have to shoot as soon as the camera gets focus.

I shoot in TV and AV, it isn't even a tracking issue, even when he is sitting still I get oof shots. examples:

From the EXIF you were at 1/60 sec., which with the 20D is right on the ragged edge of hand-holdability for your 50 f/1.8. Try upping the ISO so you can work at 1/90 or faster and see if you get any more consistently sharp results. Mind you, Tim and some others will tell you that the 50 f/1.8's inconsistent in close-focussing situations in low light so that may be coming into play here as well when that's the lens you're using. If you see this with the 18-125, use shutter speeds on the order of 1/180 or faster at the long end. Crank up the ISO if you need to. Noise is easier to clean up than camera shake.

thanks Jon, I am new to the TV and AV settings. I was having some issues with my Sigma but I'm pretty sure it is actually the lens in that case, lol.

My biggest rule at the moment is if nothing is flashing inside my eyepiece I take the shot!

on that second shot the focus seem's to be on the shirt around the shoulder.
Rob.

I have much better luck with the focus point set to center and one shot mode. If it's not on center, it will tend to focus on other things when using all 7 points

Autofocus is not reliable in low light. To increase your success rate, I'd suggest using the center focus point and prefocusing on the shirt or something with a pattern in it. Don't prefocus on the face. Also, I'd suggest using a higher f stop, like f8 to increase your range of focus (depth of field). At f 1.8, your focus range is too critical. Good luck.

thanks for all the advice, given my messy house I was going for the blurry background, hence the 1.8 tho I probably could have gone higher without revealing too much!

A few problems with this;
- prefocussing on a shirt will give you a sharp shirt, not a sharp face. If you are luck that is, 'cause focus-recompose isn't the best technique.
- When in low light, using f/8 kinda defeats the purpose of a fast lens....

@ Skrim17: did you focus between the landscape and portrait shot? If not, that's the problem. And yes, the 50/1.8 can be inaccurate.

Yes Rene, I did focus after turnning the camera. Sometimes I find the 50 a little slow and it seems you have to work a bit for accuracy.

René Damkot wrote:
A few problems with this;
- prefocussing on a shirt will give you a sharp shirt, not a sharp face. If you are luck that is, 'cause focus-recompose isn't the best technique.
- When in low light, using f/8 kinda defeats the purpose of a fast lens....

@ Skrim17: did you focus between the landscape and portrait shot? If not, that's the problem. And yes, the 50/1.8 can be inaccurate.

A sharp shirt is good Rene! The face is only an inch(2.5cm) away from the shirt and with f8, the depth of field will include the face. It does work alot better than any other technique I've tried (except manual focus). At least you know you have a focus point. Focusing on the face may be way off focus. I would suggest focusing on the interface between the face and the shirt to give the camera a contrast interface. Besides, I think the above photos were taken with flash at a distance close enough for the built in flash to work at f8 and 1/100 or 1/250 (camera on manual).

If you find this with most of the images with the Sigma it's the lens.

I have this lens and it miss focuses a lot. Sometime it's spot on but others it's not, I shot with it at f8 and use centre spot focus, I also press the shutter half way twice before shoting and I always snap two to three images to make sure.

Dont use this lens much now becasue the other lenses I have are almost perfect in focus and you notice how bad the Sigma can be when you use both.

The 50mm 1.8 can have dodgy focus now and then, mine did and I sold it for the 1.4 which makes a big difference.

If you treat your self to the 60mm macro you will never use your Sigma again. Just got this lens four days ago and it's amazing, it you want I can show you some shots with it.

R

Well, the shots were taken with fill flash, at 1/60s f/1.8 at ISO 800 going by the exif. Using f/8 would have resulted in a black background...
On f/1.8 DoF is way too shallow to focus on anything but the part you want in focus.
(on f/8 you might get by, and having a focus lock on the shirt instead of no focus at all is obviously preferable. I think it's the wrong solution to the problem however...)