I am using EOS 350D using 18-55 kit lens. Still new to DSLR...When I shoot couple/3-4people, the focus point often only point toone person, and hence the person(s) next to the focus is oftenslightly off focus. If I manually choose the focus point, then Istill only get to choose one point. Problem gets worse if I shootcouple, where the auto focus will only fix on one head... Your adviceis greatly appreciated..

This sounds rather odd. If the people are in a row in front of you, all about the same distance from the camera, then if the focus locks on any one they should all be in focus and it should not matter which one the autofocus chooses..

The only case where this would not happen is if the people are standing at different distances from you, one behind the next, so that if you focussed on the front person the people behind would be out of focus..

If you are using the telephoto end of the lens (55mm), and the widest aperture (f/5.6), and the people are quite close, there may be a depth of field problem. Have a look at.

Http://www.dofmaster.com/dofjs.html.

WIth your camera, lens at 55mm, f-stop at 5.6, and distance set to 8 feet, the depth of field (the distance from you that will be in focus) extends from 7.4 to 8.7 feet. So if one person is standing more than a few inches in front of, or behind, another, one person may be out of focus. You can correct this by using a narrower aperture, say f/11: under these conditions the depth of field extends from 6.8 to 9.6 feet, all of which will be in focus..

So... make sure your subjects are all about the same distance from the camera, and use a smaller aperture. And - important - focus on the eyes, especially if the subject is close to the camera.Mike..

Thanks for the lesson of DoF. Will do some experiment and practice. Have been using the P mode so far, did not pay attention to the f value...

Thanks for the lesson of DoF. Will do some experiment and practice.Have been using the P mode so far, did not pay attention to the fvalue..

Try aperture priority mode (usually called Av or something like it on the selector). This is the most widely used auto mode. In this mode you choose the aperture you want (say, f/11 to get a reasonable depth of field) and the camera sets the shutter speed. Just check that the shutter speed is fast enough that you can hold the camera steady, say 1/60 sec at the wide-angle end of your lens and 1/125 at the tele end (or faster)..

If the shutter speed comes out too slow, you can increase the ISO (the sensitivity of the detector) so that you can still use a short shutter speed. this has a small price in terms of slightly noisier images, but it's marginal and not a problem at typical print sizes - and it is much better to have that than to have a blurred shot because you couldn't hold the camera steady at 1/30 sec for example..

Best wishesMike..

Shipng wrote:.

Thanks for the lesson of DoF. Will do some experiment and practice.Have been using the P mode so far, did not pay attention to the fvalue..

In theory your camera can do this automatically with the A-Dep mode, which uses all the focus points to calculate the necessary depth of field and set the aperture accordingly. I've never tried it on my 400D so not sure how well it works but it might be worth a try..

Androohttp://Androo.smugmug.com..

Or, if you don't have a-dep, focus about 1/3 of the way into the group* & use the smallest aperture you can get away with - maybe boost the ISO to do so..

* 1/3 because the depth of focus in front of the focal plane is less than that behind...

Focus 1/3? is that to be done by manual focus?.

I have no confidence with my eyesight (well, tried a couple times, it turned out blur compared to autofocus...).Yes there is A-Dev, but not yet really know how to use it.....

Shipng wrote:.

Focus 1/3? is that to be done by manual focus?I have no confidence with my eyesight (well, tried a couple times, itturned out blur compared to autofocus...).Yes there is A-Dev, but not yet really know how to use it....

A-DEP is an automatic mode, so you just switch to it and fire away. You'll notice several of the focus points light up. Give it a try..

Focusing 1/3 into the scene just means aiming the camera roughly a third into the scene so it can get a focus lock there. You don't have to be too exact or use manual focus, as long as there's something there to lock focus onto..

Androohttp://Androo.smugmug.com..