BirdForum is the net's largest birding community dedicated to wild birds and birding, and is absolutely FREE!

Register for an account to take part in lively discussions in the forum, post your pictures in the gallery and more.

Reply to thread

Message: <blockquote data-quote="Roy C" data-source="post: 1166501" data-attributes="member: 18798">Having owned a 350D, 30D and 40D it is my opinion that the AF on the 40D is better than the other two cameras, especially in low light. I have read thousands of threads from different forums and the vast majority of people who mention AF problems are those who do not actually have the 40D but have heard rumors. I think a lot of this has stemmed from the threads about using a taped tc and the centre focus point. This has nothing to do with the cameras general  AF abilities. I shoot birds almost all the time with AI servo mode and it is superb. I have had more success with birds in flight with the 40D than I ever did with the other two cameras.The centre focus point is more sensitive and with a f2.8 lens it can distinguish between less contrast area's and thus improve focus capabilities.This seems to has a knock-on effect with slower lenses and can have its drawbacks if you focusing accuracy is off.  if you lose position of a bird in flight  the AF will lock right on to something else if the AF is not over the bird, this is because the AF is better!.With my other cameras AI servo was so sluggish that even if you lost the bird over an AF point it would still be near enough in focus for a while until it finally locked on to something else - the 40D is not so forgiving because its AF is better.</blockquote>