AI Servo or Single Shot?

[Tortie]

If I'm trying to take pictures of my moving cat but want as accurate focus as possible on her eyes, should I be in AI Servo or Single Shot AF?

I usually use Single Shot because.. well, I guess I think that I have a better shot of nailing the focus (since I'm telling the camera where to focus). I always thought that using AI Servo (while it should follow the subject) will not know that I want the eyes in focus or something along those lines, ha.

I suppose I should just go, experiment, and shoot but I'd like to know what your suggestions are as well as how you approach getting the eyes in focus.

Cheers!

[themadman]

I would say give both a try and see which works well for you. Cats move pretty fast, good luck with those photos!

[deci]

Mmmmmmmmmmm.......... For my cat shots I usually use single shot. I'm thinking AI Servo will always default to the chosen point? I'm probably wrong, but like you "How would it know?", unless you where accurately tracking.

[Tortie]

Thanks for the input, you two!

From my experimenting, I seem to get more keepers from using Single Shot. Even if I do continue to track with AI Servo, it seems that all my pictures are soft or focused elsewhere.

Feel free to add more suggestions and experiences.

[Meanderthal]

I for one don't have the skill nor the auto-focus lens speed that can fix on the eye of a moving cat. The Action Mode of your camera uses AI Servo, does it not? Assuming that Canon engineers know what they are doing, the issue may be elsewhere. Perhaps just ensure that the depth of field covers the entire cat and a bit more.

[Tortie]

That's a good point and another reason I probably don't get as many keepers as I would like. I'm usually using a wide aperture, between 1.8 and 2.8. The main reason? She's indoors so I don't get as much light to work with as for my dog (for example).

I'll have to play around with AI Servo more. It's probably a matter of getting the hang of it also.

[Meanderthal]

Ah, you are using the 50mm 1.8 wide open. No wonder, the DOF at those apertures is exceedingly narrow. See http://www.dofmaster.com/dofjs.html, it will be a real "eye opener" (pardon the pun). Would a flash bother the cat? The XTi has a flash sync speed of 1/200 sec. Read up on that in your camera manual, it may help. Good luck. Hugs to the cat.

[Tortie]

I knew how narrow the DOF got when using such a wide aperture, but for some reason that hadn't come into play as a possibility. Thanks! I'm such a stickler when it comes to nailing focus so that's just it, I'll have to learn to work stopped down a bit.

I actually don't have a flash yet. I've been thinking about getting a cheap(er) one to decide whether I'd like it. The only thing is, as you said, I don't really want to bother the cat with flash. I mean, if I did get one, I'd bounce it off the ceiling or get a diffuser but I'd rather use whatever ambient light is available.

Thanks for your help.

[mkett]

I know for my dogs I use the servo mode because they seem to move sometimes just as you are getting the right shot.

[jaeapla]

I have tried it both ways and had better luck with AI Servo -- these animals are always moving. One of the tricks I have learned is to shoot a dog with a long snout from a side or three-quarter view (at f/8 or f/11 if possible).Unless your aperture is closed dowm you will get an elongated snout in focus, and the rest of the face will have varying degrees of sharphess and distortion.

If you must shoot from the front (face-on). Minimize the aperture opening and use a telephoto zoom for the portrait. Again, play with the optimal location.

[x002x]

from my own personal experiences i tend to use ai-servo mode with a smaller aperture (f/8-f/16), keep the lens zoomed out until my shot comes up, then zoom in at the right moment and burst away.

[KellyL]

How do you get the camera from AI Focus to AI Servo mode? I have tried to follow the manua's directions, but can't get to AI Servo setting and can't get to the "H" for high speed continuous???

[Tortie]

KellyL, what camera are you using? Make sure you're using one of the creative modes (Av, Tv, or M). I only have experience with an XTi but, if you look at THIS (http://www.dcviews.com/press/images/Canon-XTi-400D.jpg) picture (the back of the camera, on the bottom), to change from single to continuous shot, you'd push the second button on the right of the LCD screen (under the button that says Av). To change from AI Focus to AI Servo, you'd push the right button on the control pad (the rightmost button of the four in a circle) and choose from there. I hope that made sense, ha.

EDIT: Also, welcome to PotN!

[~Sally~]

i use AI servo when i take photos of my dogs, it took me a while to get used to it but i prefer it to single shot AF. i find that if i focus the shot as close to taking it as possible i tend to get better results (before they move etc)

[smilebug]

AI servo for sure. It's much easier because a dog is always running around and a one shot thing, well, it's in the name. One shot, it's not fast enough for a dog is it? :)

[philwillmedia]

If I'm trying to take pictures of my moving cat but want as accurate focus as possible on her eyes, should I be in AI Servo or Single Shot AF? ...

Just like with sports photography AI Servo. It's constantly focusing whilst tracking.
With one shot it focuses, takes the shot. then focuses and takes the shot again etc etc.
By the time it's taken the shot the moving subject has moved out of focus and you end up with a missed shot. It then needs to refocus for the next shot.
As the name suggests, it's just one shot at a time.

...I usually use Single Shot because.. well, I guess I think that I have a better shot of nailing the focus (since I'm telling the camera where to focus). I always thought that using AI Servo (while it should follow the subject) will not know that I want the eyes in focus or something along those lines, ha.
...

...I'm thinking AI Servo will always default to the chosen point? I'm probably wrong, but like you "How would it know?", unless you where accurately tracking...

The camera does what you tell it to and it will focus on the point you have the camera set to.
If you have it set on the centre focus point, that's where the focus will be.
If you have it set to the top left for example, that's where the focus will be etc.
If you want the eyes and the focus point is tracking the middle of it's back, that's what will be in focus.

How do you get the camera from AI Focus to AI Servo mode? I have tried to follow the manua's directions, but can't get to AI Servo setting and can't get to the "H" for high speed continuous???

You need to have the camera out of "Green Box" mode

[aprikh1]

Single Shot seems to work best for me...