20D non-centre focus point accuracy

[tim]

I've been using the non-centre focus points quite a lot lately, and i'm a bit disappointed with the performance of the non-centre focus points. I usually shoot at F2.8 or F4 in reasonable light, and I find 30-40% of the shots aren't focused where I selected.

Is this consistent with other peoples experience, or is it me?

I read today the 1D Mk II has 9 cross type focus sensors, to the 20D's one... dag nabbit!

[Wavy C]

About the only time I ever use the non-centre focus points are for close-up portraits - especially with my 85mm 1.8.. Otherwise I use the centre point only for general photography.

When shooting portraits I select the focus point furthest to the left, turn the camera upright and use that point to focus on the subject's eyes. Have found this gives better results than using the centre point and then recomposing, as the 85mm has a very shallow dof at wide apertures. It does, however, sometimes cause the lens to hunt a little before it finds focus.

This normally gives me pretty sharp pictures - when using focus and recompose with the centre point I sometimes thought myself lucky to get 50% of shots in sharp focus!

When I first got my 20D about three months ago I had a lot of problems getting pictures in focus. This was very annoying and I found myself starting to check every shot in the lcd to reassure myself I had a good picture. The only thing that really worked was to let the camera focus, then doing a manual fine-tune by looking through the viewfinder and turning the focus ring slightly.

[drisley]

When shooting portraits I select the focus point furthest to the left, turn the camera upright and use that point to focus on the subject's eyes.
Don't you mean you select the point on the right and then turn to portrait mode (ie, counter clockwise). If you select the left point, you would be focused on the person's nether regions :lol:

[CyberDyneSystems]

Drisley it depends how you shoot portrais. Without the grip,. many turn the camera the other way for a more stable grip.

Tim.. No i do not think your results are normal.
I shoot with off center focus points quite a lot ( and I mean a LOT) and have not seen a dramatic difference in accuracy at all compared to the center point. I have been doing with the 20D, MkII and 10D previously.. all with similar if not Identical results to using the center point.

Slightly OT,. The ONE and ony thing about the 20D which I preferred on the 10D was is the layout of the focus points. On the 10D I had two focus points to left and two to right of the centre to chose from. I found I used the one closer to the center the center more often.. but did use both. With the 20D I don't have that option.

[Jopox]

Being new to digital and AF after years of manual focusing on film SLRs, I had focusing problems with my earlier photos. AF needs some getting used to, in my case, but I'm slowly learning, such as by doing manual fine-tuning.

[drisley]

Drisley it depends how you shoot portrais. Without the grip,. many turn the camera the other way for a more stable grip..
Really? That seems so awkward! :eek:

Slightly OT,. The ONE and ony thing about the 20D which I preferred on the 10D was is the layout of the focus points. On the 10D I had two focus points to left and two to right of the centre to chose from. I found I used the one closer to the center the center more often.. but did use both. With the 20D I don't have that option.
I agree. An 11 point AF system would be very nice.

[tim]

Thanks guys, maybe I just need to work on my technique. I do get a lot of shots that are perfectly in focus even at F2.8, but some aren't probably less than 30% - maybe around 10-15%. Must try to use the monopod more often.

[Jon]

As I read WavyC's description, with the camera vertical, he selects the left-most focus point, turns the camera upright (landscape mode) and focusses using that point (which is now the top); then restores the camera to vertical, finishes recomposing and shoots. If you have the camera on a tripod, it'll seem quite straightforward.