I photograph primarily slow moving wildlife which mosey around but may suddenly take off in flight. I want to be ready to capture both types of movement. I haven't been using a DSLR for a long time so have a few questions about Servo modes.

I keep my Canon XSi/450D set to AI Focus, which according to Canon, automatically switches from One Shot AF to AI Servo depending on the subjects movement.

Question: Is AI Focus mode most suitable for this type of photography?

Also, I keep my camera continually set to Continuous mode so it's there when I need it.

Question: Is it okay to use Servo and Continuous modes at the same time?

Question: Why do some recommend turning of Image Stabilization when using these modes?

Any tips for using Servo modes will be much appreciated since it's been hit and miss thus far.

Thank you very much!

That's what it's there for! I'd use center point, Servo...not the AI. You might try using the * or AF button instead of
1/2 depressing the shutter. Takes a little to get used to but I'll never go back.

trenchmonkey wrote:
You might try using the * or AF button instead of
1/2 depressing the shutter. Takes a little to get used to but I'll never go back.

Thank you for the reply.

I'm unfamiliar with using the * button for AI Servo. Please explain more fully.

I'm not sure if one can switch button functions with the rebel.

Sure ya can, it's a custom function. Read the manual.
You'd be using the * button for AF lock. My Daughter
shoots that way with one so I know it works. I set it up,
but I'm an older 'monkey and don't recall the settings.

trenchmonkey wrote:
Sure ya can, it's a custom function. Read the manual.
You'd be using the * button for AF lock. My Daughter
shoots that way with one so I know it works. I set it up,
but I'm an older 'monkey and don't recall the settings.

I guess you can then haha I was thinking of my old xti and couldn't recall if you do it.

Sure Brenton, the XT and XTi would let you. Most of the BIF and sports guys
I know shoot that way. When I teach beginners I start out 'em out using the * button
to get in the habit. No one's complained.

Thanks for the info. I had two more questions:

Question: Is it okay to use Servo and Continuous modes at the same time?

Question: Why do some recommend turning of Image Stabilization when using these modes?

Any suggestions or advice. Thank you.

Question: Is it okay to use Servo and Continuous modes at the same time?

* perfectly fine to use these two the same time, My camera is set up like this 90% of the time.

Question: Why do some recommend turning of Image Stabilization when using these modes?

* not sure who doesn't recommend this, but I do The only time I might not use "IS" is using a tripod, but most new lens with "IS" can detect if they are on a tripod, so turning this off is not really necessary.

Also, take advantage of every opportunity to get more familiar with tracking the subject, start tracking the subject in flight before they reach you, this will allow the camera to adjust and better focus.

Image Stabilization will slow down the focus speed by a split second. If you want really fast focus speed, turn it off. Especially if you are shooting flight, you will want a shutter speed of 1/1250 and faster if possible......IS isn't going to help much at the higher speeds anyhoo.

AI Servo is much better than AI Focus for flight or action shots. Even shotss that aren't moving much, the AI Servo will keep focus lock if they are moving a bit, where the AI Focus won't pop out of One Shot mode.

Hey the King of BIF (J.M.) is right as I see it. I also will turn off the IS on my glass so if I am going for BIF but I also turn it off when watching a certain spot for something to take place as it makes noise when it runs and I have seen a red tail take notice of me pushing the shutter button ½ and the IS noise starting make it take off and it is a 150 feet from me. I also will say the IS on one glass may make more noise than that on another. My 500 seems to make more noise when running than my 1 to 400. Go figure.
Lou

Hey Trench, thanks for the * Advice..I have to DL my manual (At work) and give it a try.

Ok I got two options.. which one do I want..

AE/AF No AE lock
Or
AF/AE Lock

Oooh the choices.. I guess I will have to play with it..Since you can't really tell me which one to use..

Beautiful.. LOVE it.. Now I don't have to wait for my danged Autofocus to decide what to focus on..

Thanks for all the very helpful information. I'll switch to full fledged AI Servo. I need lots of practice.

The reason not to use IS is because it only stops your movement not the subjects. If your movements are too great, like being on a rocking boat, only a high shutter speed will stop the movement of both you and the subject. If you climb up a steep hill with a heavy telephoto and are taking a photo of a still or slow moving subject than that is the time to use IS. Unless you are panting too hard.

A quick question about AI Servo. When the subject is NOT moving, does the focus accuracy suffer? I like to stalk birds and since they usually see me before I see them, most of my shots are takeoff and in flight. 40D is set to get at least 1/1000th shutter speed and AI Servo with * button for focus. Seems to work pretty good when I do my part. Sometimes I spot the bird before he takes flight and I can get some perch shots. For these the focus seems to wander and not lock in like in One Shot mode. I don't want to miss the takeoff shot, so I don't want to change focus mode if i don't have to. Is AI Servo less precise in its ability with non-moving subjects?

Mike

mt2mt2 wrote:
A quick question about AI Servo. When the subject is NOT moving, does the focus accuracy suffer? I like to stalk birds and since they usually see me before I see them, most of my shots are takeoff and in flight.

I'm back, and have the same question. Hope someone can answer it.

Thank you!

72chevelle454 wrote:
Also, take advantage of every opportunity to get more familiar with tracking the subject, start tracking the subject in flight before they reach you, this will allow the camera to adjust and better focus.

Can you be more specific about what you're suggesting here?

Do I push the shutter-button halfway immediately as I start tracking? Or keep tracking until the subject is correctly in the frame, and then push the shutter button and track?

I'm not even sure if I keep the shutter button half-way, or press it fully down and keep it down while tracking.

So far, I'm following these suggestions as to modes and settings when lighting is good:

Center focus point
AI Servo mode
Fast shutter speed, around 1600
Exposure Compensation between -1/3 and +1/3, depending on the scene and lighting

Thank you.

Not to steal the thread, but I'm following this subject matter closely as I learn the best technique for BIF. Have to ask a REALLY stupid question though, what is "continuous focus" mode? (See, I told you it was a stupid question, but I really need to know). Is this just another way of saying "auto-focus"?

Jo