frustrated-how to select center point as default

search the forum and found lots of threads about this subject but cannot figure out how to actually do it. I have been having problems with camera not focusing on the right(chosen) subject. I know how to manualy select AF point and how to achieve manual focusing, but would like to permanently use center point.

Second question - What metering mode do you typically use?

Third question - for taking photos of hurdles with 50 f/1.4 on cloudy, rainy dark day what shutter speed and aperture would you select to freeze the action?

will appreciate any help,

m

Do you have the camera manual? Which camera are we talking about? Its very simple on the XT, 20D and 30D that I know of. Just press the button on the far right at back and turn the thumb wheel to the center focus point. Can't be in the Auto Mode

what camera? do you have the manual? it should state how to set the AF points. Metering really depends on the scene your trying to capture.

rainy dark day, youll need to bump up the ISO pretty high to get a fast shutter speed, as for Aperture.. youd have to be pretty close to the action with the f1.4 so's as not to loose the sharpnes due to the extremely shallow DOF with that lens. f1.4 will help let in allot of light but if your far away the DOF will "soften" the shot.
-zacker-

zacker: I think you've got that one turned around. Since DOF is a percentage of the focus distance, as the distance increases the actual physical DOF increases. If when focussed at 1.0 meter you have DOF from 0.95m to 1.05m, at 10 meters the DOF will be 9.5m to 10.5m. Of course your subject will be correspondingly reduced in size, so backing away is not a good way to get more DOF (hehe).
Elie

For metering it depends on the situation.. each has its uses. I tend to use partial as I do alot of low-light shooting and want to expose for performers and not the backgrounds. I'd use spot if I had it (20D).

and what shutter speed? well you'd probably want at least 1/125th to freeze people moving at all, let alone action.. bump up the ISO to as high as necessary and set your aperture wide enough to get the shutter speed which will suitably freeze the action. If it's really fast action you'll be needing really high shutter speeds, experiment and see what works

lol... you are correct! depending on the distance, what i ment was, the front part only would be sharp and the rest wont due to DOF.. depending on what the focus selects as its point. Like my dog, if i focus on his nose, its sharp but because of the DOF being what it is on my 50.. (f1.8) his eyes start to Bokeh abd its all bokeh from there back. Its a great lens just kinda tricky at times.. -zacker-

Marysia asked about making the center AF the "default." On the XT/20D etc line, the camera will leave it to where it's set as long as you don't go into one of the auto modes; once set to center AF it should stay there. But if you go into an auto mode it switches to using all AF points.

The 1D cameras have a personal function that lets you set the defaults for AF and other settings, and the cameras have a "reset" feature that takes it back to the default setting.

I am sorry I did not mention which camera I have. 30d. And I do have manual. Page 77 deals with the question. I was just under impression that I will have to do it every time I take photo.

Thanks so much DavidEB for understanding my very unclear question and giving me precise answer I needed.

Regarding metering. I think I like spot metering the best. I understand that you change it depending on situation but which one do you use most often? Is it fair question?

Regarding taking photos of racing JRTs(hurdles). I was thinking of using 50 f/1.4 because it will be dark rainy day and I will need as much light as I can get to end up with high shutter speed/ aparture combination. Do you think that 70-200 would get me better DOF? I only have f/4 so light may be a problem.

Thanks for your help. I just love this forum and all helpful advices.

m

Assuming the 30D has custom functions similar to the 20D, there is a CF which allows you to change the AF point via the joystick button. It's much quicker to use, in my opinion.

On the 20D the custom function Curtis N is refering to is CF 13 - if you set it to 1 you can use the multi-controller joy stick to select any AF point, pushing the multi-controller joy stick straight down selects the centre focus point only. Pushing the button with the dots in a cross formation (upper right hand of camera back) reverts to auto focus point selection. I find this setup to be very quick and easy to use, however, with the grip on and the camera in portrait orientation it is difficult to reach the multi-controller. Setting CF 13 to 2 allows you to select focus points using the quick control dial. Although I've never used this setup I suspect it would work much better with the grip on and the camera in portrait orientation since you wouldn't have to reach as far to change AF points.

I always seem to bump the joystick on my 20D and it results in different points being selected, but it's easy to fix.

on a 20D you have to press a button on top, then turn the wheel to select the AF point, turning the wheel alone wont change it.

CF-13 is your friend, as described above. CF13-0 will behave as you describe. CF13-1 will enable you to set AF points directly with the joystick; CF13-2 will enable you to set AF points direct with the Quick Dial (and EC with the AF-point selector and Quick Dial; it reverses the two roles).

DOH yeah stupid me! i forgot all about those custom fuctions

Regarding spot metering: It can be tricky because you need to meter off a medium tone or know how much to compensate if the metered area is lighter or darker.
About DOF: For a given image size and f-stop the DOF does not change if you switch lenses or zoom. In other words, with the 50 you may need to be right down at the rail to get good shots while with the 200 you can get the same shot from 4 times the distance (away from the flying mud). The 50 might give DOF that is 10% of the focus distance (at a certain f-stop) and the 200 would give only 2.5% (at the same f-stop), but since the focus distance is x4 the DOF is the same. There might be an advantage to the 50 in that it can be handheld at slower speeds, but in your case the shutter speed will be dictated by the need to freeze the action.
Elie